NXP Semiconductors | Automotive, Security, IoT · MC33215 4 MOTOROLA ANALOG IC DEVICE DATA...

DeviceOperating

Temperature Range Package

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ORDERING INFORMATION

MC33215FB

MC33215BTA = –20° to +70°C

TQFP–52

SDIP–42

B SUFFIXPLASTIC PACKAGE

CASE 858(SDIP–42)

Order this document by MC33215/D

FB SUFFIXPLASTIC PACKAGE

CASE 848B(TQFP–52)

52 1

42

1

1MOTOROLA ANALOG IC DEVICE DATA

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The MC33215 is developed for use in fully electronic telephone sets withspeakerphone functions. The circuit performs the ac and dc line termination,2–4 wire conversion, line length AGC and DTMF transmission. Thespeakerphone part includes a half duplex controller with signal and noisemonitoring, base microphone and loudspeaker amplifiers and an efficientsupply. The circuit is designed to operate at low line currents down to 4.0 mAenabling parallel operation with a classical telephone set.

• Highly Integrated Cost Effective Solution• Straightforward AC and DC Parameter Adjustments• Efficient Supply for Loudspeaker Amplifier and Peripherals• Stabilized Supply Point for Handset Microphone• Stabilized Supply Point for Base Microphone• Loudspeaker Amplifier can be Powered and Used Separately• Smooth Switch–Over from Handset to Speakerphone Operation• Adjustable Switching Depth for Handsfree Operation

Simplified Application

This device contains 2782 active transistors.

Attenuator

DTMF

Attenuator

DuplexController

LineDriver

CurrentSplitter

1:10

HandsetMicrophone

BaseMicrophone

VCC or External Supply

Base Loudspeaker

Auxiliary Input

Handset Earpiece

Receive Signal

TelephoneLine

VCC Supply

DC Slope

Line CurrentDC Offset

ACImpedance

RxLS

BM

HM

MF

This document contains information on a new product. Specifications and information hereinare subject to change without notice.

Motorola, Inc. 1997 Rev 0

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For More Information On This Product, Go to: www.freescale.com

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MC33215

2 MOTOROLA ANALOG IC DEVICE DATA

FEATURES

Line Driver and Supply• AC and DC Termination of Telephone Line• Adjustable Set Impedance for Real and Complex

Termination• Efficient Supply Point for Loudspeaker Amplifier and

Peripherals• Two Stabilized Supply Points for Handset and Base

Microphones• Separate Supply Arrangement for Handset and

Speakerphone Operation

Handset Operation• Transmit and Receive Amplifiers• Differential Microphone Inputs• Sidetone Cancellation Network• Line Length AGC• Microphone and Earpiece Mute

• Separate Input for DTMF and Auxiliary Signals• Parallel Operation Down to 4.0 mA of Line Current

Speakerphone Operation• Handsfree Operation via Loudspeaker and Base

Microphone• Integrated Microphone and Loudspeaker Amplifiers• Differential Microphone Inputs• Loudspeaker Amplifier can be Powered and Used

Separately from the Rest of the Circuit• Integrated Switches for Smooth Switch–Over from

Handset to Speakerphone Operation• Signal and Background Noise Monitoring in Both

Channels• Adjustable Switching Depth for Handsfree Operation• �� Switch–Over ��

• Dial Tone Detector in the Receive Channel

TQFP–52

Figure 1. Pin Connections

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

42

41

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

1

2

3

4

5

6

7

8

9

10

11

12

13

14 15 16 17 18 19 20 21 22 23 24 25 26

39

38

37

36

35

34

33

32

31

30

29

28

27

52 51 50 49 48 47 46 45 44 43 42 41 40

SLB

REG

SLP

MFI

HM1

HM2

BM2

BM1

VDD

TSA

TSE

TBN

MUT

LSF

BVO

PPL

LSI

VOL

SWD

REF

AGC

Gnd

RLS

RSA

RSE

RBN

SLB

REG

SLP

MFI

HM1

HM2

BM2

BM1

VDD

TSA

TSE

TBN

MUT

VCC

VLN

VHF

VMC

SPS

PRS

SWT

LSM

LSF

BVO

PPL

LSI

VOL

SWD

REF

AGC

Gnd

RLS

RSA

RSE

RBN

RXI

GRX

RXO

RXS

PGD

LSO

VLS

LSB

(Top View)

(Top View)

N/C

N/C

N/C

N/C

SPS

PRS

SWT

LSM

N/C

RXS

RXO

GR

X

RXI

N/C

N/C

N/C

N/C

VMC

VHF

VLN

CC

N/C

PGD

LSO

VLS

LSB

V

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MC33215


MAXIMUM RATINGS

Rating Min Max Unit

Peak Voltage at VLN –0.5 12 V

Maximum Loop Current – 160 mA

Voltage at VLS (if Powered Separately) –0.5 12 V

Voltage at VHF (if Externally Applied) –0.5 5.5 V

Voltage at SPS, MUT, PRS, LSM –0.5 7.5 V

Maximum Junction Temperature – 150 °C

Storage Temperature Range –65 150 °C

NOTE: ESD data available upon request.

RECOMMENDED OPERATING CONDITIONS

Characteristic Min Max Unit

Biasing Voltage at VLN 2.4 10 V

Loop Current 4.0 130 mA

Voltage at VLS 2.4 8.0 V

Voltage at VHF (if Externally Applied) 2.4 5.0 V

Voltage at SPS, MUT, PRS, LSM 0 5.0 V

Operating Ambient Temperature Range –20 70 °C

ELECTRICAL CHARACTERISTICS (All parameters are specified at T = 25°C, Iline = 18 mA, VLS = 2.9 V, f = 1000 Hz,PRS = high, MUT = high, SPS = low, LSM = high, test figure in Figure 17 with S1 in position 1, unless otherwise stated.)

Characteristic Min Typ Max UnitÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

DC LINE VOLTAGEÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Line Voltage Vline ÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁ

VParallel Operation, Iline = 4.0 mA – 2.4 –

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁIline = 20 mA ÁÁÁÁÁ3.9 ÁÁÁÁ4.2 ÁÁÁÁ4.5 ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Iline = 70 mAÁÁÁÁÁÁÁÁÁÁ

4.8 ÁÁÁÁÁÁÁÁ


5.6 ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁSUPPLY POINT VDD

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Internal Current Consumption from VDD ÁÁÁÁÁÁÁÁÁÁ

– ÁÁÁÁÁÁÁÁ



mAVDD = 2.5 VÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁSUPPLY POINT VMCÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDC Voltage at VMC (= VMC0)

ÁÁÁÁÁÁÁÁÁÁ1.6

ÁÁÁÁÁÁÁÁ1.75

ÁÁÁÁÁÁÁÁ1.9

ÁÁÁÁÁÁÁÁVÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁCurrent Available from VMCÁÁÁÁÁÁÁÁÁÁ1.0

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁmAVMC = VMC0 – 200 mV

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

SUPPLY POINT VHF


DC Voltage at VHF (= VHF0) ÁÁÁÁÁÁÁÁÁÁ




V


Internal Current Consumption from VHF ÁÁÁÁÁÁÁÁÁÁ




mAVHF = VHF0 + 100 mVÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁCurrent Available from VHFÁÁÁÁÁÁÁÁÁÁ2.0

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁmAVHF = VHF0 – 300 mV


SUPPLY POINT VCCÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Current Available from VCC ÁÁÁÁÁÁÁÁÁÁ

13 ÁÁÁÁÁÁÁÁ

15 ÁÁÁÁÁÁÁÁ


mA


VCC = 2.4 V, Iline = 20 mA ÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDC Voltage Drop Between VLN and VCC

ÁÁÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ1.0

ÁÁÁÁÁÁÁÁ1.5

ÁÁÁÁÁÁÁÁVÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁIline = 20 mA

ÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁ


ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁSUPPLY INPUT VLS


Internal Current Consumption from VLS ÁÁÁÁÁÁÁÁÁÁ




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MC33215


ELECTRICAL CHARACTERISTICS (continued) (All parameters are specified at T = 25°C, Iline = 18 mA, VLS = 2.9 V, f = 1000 Hz,PRS = high, MUT = high, SPS = low, LSM = high, test figure in Figure 17 with S1 in position 1, unless otherwise stated.)

Characteristic UnitMaxTypMin


LOGIC INPUTS

Logic Low Level Pins PRS, MUT, SPS, LSM – – 0.4 V

Logic High Level Pins PRS, MUT, SPS, LSM 2.0 – 5.0 V

Internal Pull Up Pins PRS, MUT, LSM – 100 – kΩ


Internal Pull Down Pin SPS ÁÁÁÁÁÁÁÁÁÁ


100 ÁÁÁÁÁÁÁÁ


kΩ


Tx CHANNEL, HANDSET MICROPHONE AMPLIFIER


Voltage Gain from VHM to Vline ÁÁÁÁÁÁÁÁÁÁ

46 ÁÁÁÁÁÁÁÁ

47 ÁÁÁÁÁÁÁÁ

48 ÁÁÁÁÁÁÁÁ

dBVHM = 1.5 mVrmsÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁGain Reduction in Mute Condition


60ÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ

dBMUT = Low or PRS = Low or SPS = High


Input Impedance at HM1 and HM2 ÁÁÁÁÁÁÁÁÁÁ

14 ÁÁÁÁÁÁÁÁ

18 ÁÁÁÁÁÁÁÁ

22 ÁÁÁÁÁÁÁÁ

kΩ


Common Mode Rejection Ratio ÁÁÁÁÁÁÁÁÁÁ


50 ÁÁÁÁÁÁÁÁ


dB


Total Harmonic Distortion at VLN ÁÁÁÁÁÁÁÁÁÁ




%VHM = 4.5 mVrmsÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁPsophometrically Weighted Noise Level at VlineÁÁÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ–72

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁdBmpHM1 and HM2 Shorted with 200 Ω


Tx CHANNEL, BASE MICROPHONE AMPLIFIER (SPS = HIGH, T x MODE FORCED)


Voltage Gain from VBM to Vline ÁÁÁÁÁÁÁÁÁÁ

53 ÁÁÁÁÁÁÁÁ


58 ÁÁÁÁÁÁÁÁ

dBVBM = 0.5 mVrmsÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁInput Impedance at BM1 and BM2ÁÁÁÁÁÁÁÁÁÁ14

ÁÁÁÁÁÁÁÁ18

ÁÁÁÁÁÁÁÁ22

ÁÁÁÁÁÁÁÁkΩÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁCommon Mode Rejection RatioÁÁÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ50

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁdBÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTotal Harmonic Distortion at VLNÁÁÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ2.0

ÁÁÁÁÁÁÁÁ%VBM = 1.5 mV


Psophometrically Weighted Noise Level at Vline ÁÁÁÁÁÁÁÁÁÁ


–62 ÁÁÁÁÁÁÁÁ


dBmpBM1 and BM2 Shorted with 200 Ω

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁGain Reduction in Mute Condition ÁÁÁÁÁ60 ÁÁÁÁ– ÁÁÁÁ– ÁÁÁÁdBMUT = Low or PRS = Low or SPS = Low


Tx CHANNEL, DTMF AMPLIFIER (MUT = LOW OR PRS = LOW)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Voltage Gain from VMF to VlineÁÁÁÁÁÁÁÁÁÁ

34 ÁÁÁÁÁÁÁÁ

35 ÁÁÁÁÁÁÁÁ

36 ÁÁÁÁÁÁÁÁ

dBVMF = 7.5 mVrms


Input Impedance at MFI ÁÁÁÁÁÁÁÁÁÁ

14 ÁÁÁÁÁÁÁÁ

18 ÁÁÁÁÁÁÁÁ

22 ÁÁÁÁÁÁÁÁ

kΩ


Gain Reduction in Mute Condition ÁÁÁÁÁÁÁÁÁÁ

60 ÁÁÁÁÁÁÁÁ



dBMUT = High or PRS = Low


Rx CHANNEL, EARPIECE AMPLIFIERÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Voltage Gain from VRXI to VEAR (Note 1)ÁÁÁÁÁÁÁÁÁÁ

23 ÁÁÁÁÁÁÁÁ

24 ÁÁÁÁÁÁÁÁ

25 ÁÁÁÁÁÁÁÁ

dBVline = 20 mVrms



60 ÁÁÁÁÁÁÁÁ



dBMUT = Low or SPS = LowÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁInput Impedance at RXI


24ÁÁÁÁÁÁÁÁ

30ÁÁÁÁÁÁÁÁ

36ÁÁÁÁÁÁÁÁ

kΩÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Psophometrically Weighted Noise Level at VEARÁÁÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ

130ÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ

µVrmsRXI Shorted to Gnd via 10 µF


Confidence Level During DTMF Dialing ÁÁÁÁÁÁÁÁÁÁ

10 ÁÁÁÁÁÁÁÁ

15 ÁÁÁÁÁÁÁÁ

20 ÁÁÁÁÁÁÁÁ

mVrmsVMF = 7.5 mVrms, MUT = LowÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁOutput Swing Capability into 150 ΩÁÁÁÁÁÁÁÁÁÁ680

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁmVppTHD ≤2%


Output Swing Capability into 450 Ω ÁÁÁÁÁÁÁÁÁÁ




mVppTHD ≤2%, RRXO = 360 kΩ

NOTE: 1. Corresponding to –0.6 dB gain from the line to output RXO in the typical application.

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Rx CHANNEL, LOUDSPEAKER PRE–AMPLIFIER (SPS = HIGH, R x MODE FORCED)


Voltage Gain from VRXI to VRLS (Note 2) ÁÁÁÁÁÁÁÁÁÁ

21 ÁÁÁÁÁÁÁÁ

24 ÁÁÁÁÁÁÁÁ

27 ÁÁÁÁÁÁÁÁ

dBVline = 20 mVrmsÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁGain Reduction in Mute ConditionÁÁÁÁÁÁÁÁÁÁ60

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁdBSPS = Low or MUT = Low


Rx CHANNEL, LOUDSPEAKER AMPLIFIER


Voltage Gain from VLSI to VLSP ÁÁÁÁÁÁÁÁÁÁ

25 ÁÁÁÁÁÁÁÁ

26 ÁÁÁÁÁÁÁÁ

27 ÁÁÁÁÁÁÁÁ

dBVLSI = 10 mVrmsÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁAttenuation at Delta RVOL = 47 kΩÁÁÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ32

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁdBÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁPsophometrically Weighted Noise Level at VLSPÁÁÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ1.2

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁmVrmsRXI Shorted to Gnd via 10 µF


Confidence Level During DTMF Dialing ÁÁÁÁÁÁÁÁÁÁ




mVrmsVMF = 7.5 mVrms MUT = Low


Available Peak Current from LSO ÁÁÁÁÁÁÁÁÁÁ




mApeak

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁOutput Capability into 25 Ω ÁÁÁÁÁ1.8 ÁÁÁÁ– ÁÁÁÁ– ÁÁÁÁVppTHD ≤2%, VLSI = 55 mVrmsÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁOutput Capability into 25 Ω ÁÁÁÁÁ

ÁÁÁÁÁ2.7ÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ

VppTHD ≤2%, VLS = 5.0 V, VLSI = 90 mVrms



60 ÁÁÁÁÁÁÁÁ



dBLSM = LowÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁRx CHANNEL PEAK–TO–PEAK LIMITERÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁPeak–to–Peak Limiter Attack Time


–ÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ

5.0ÁÁÁÁÁÁÁÁ

msVLSI Jumps from 40 mVrms to 120 mVrms


Peak–to–Peak Limiter Release Time ÁÁÁÁÁÁÁÁÁÁ




msVLSI Jumps from 120 mVrms to 40 mVrmsÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTHD at 10 dB OverdriveÁÁÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ7.0

ÁÁÁÁÁÁÁÁ%VLSI = 120 mVrms


Peak–to–Peak Limiter Disable Threshold at PPL ÁÁÁÁÁÁÁÁÁÁ




V


AUTOMATIC GAIN CONTROL


Gain Reduction in Transmit and Receive Channel with Respect to Iline = 18 mA ÁÁÁÁÁÁÁÁÁÁ




dBIline = 70 mAÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


Gain Variation in Transmit and Receive Channel with Respect to Iline =18 mA withAGC Disabled (AGC to VDD)

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁÁÁÁÁ

1.5ÁÁÁÁÁÁÁÁÁÁÁÁ

dB


Highest Line Current for Maximum Gain ÁÁÁÁÁÁÁÁÁÁ


20 ÁÁÁÁÁÁÁÁ


mAÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Lowest Line Current for Minimum Gain ÁÁÁÁÁÁÁÁÁÁ


50 ÁÁÁÁÁÁÁÁ


mAÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

BALANCE RETURN LOSSÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Balance Return Loss with Respect to 600 Ω ÁÁÁÁÁÁÁÁÁÁ

20 ÁÁÁÁÁÁÁÁ



dB


SIDETONE


Voltage Gain from VHM to VEAR ÁÁÁÁÁÁÁÁÁÁ



28 ÁÁÁÁÁÁÁÁ

dBS1 in Position 2ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁLOGARITHMIC AMPLIFIERS AND ENVELOPE DETECTORSÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁVoltage Gain from RXI to RSA

ÁÁÁÁÁÁÁÁÁÁ18

ÁÁÁÁÁÁÁÁ20

ÁÁÁÁÁÁÁÁ22

ÁÁÁÁÁÁÁÁdBVRXI = 15 mVrms


Voltage Gain from BMI to TSA ÁÁÁÁÁÁÁÁÁÁ




dBVBM = 0.5 mVrmsÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDynamic Range of Logarithmic Compression from TSA to TSE and RSA to RSEÁÁÁÁÁÁÁÁÁÁ40

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁ–

ÁÁÁÁÁÁÁÁdB

ITSA and IRSA from 2.5 µA to 250 µAÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Envelope Tracking Between TSE and RSE and Between TBN and RBN ÁÁÁÁÁÁÁÁÁÁ


±3.0 ÁÁÁÁÁÁÁÁ


dBÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Maximum Source Current from TSE or RSE ÁÁÁÁÁÁÁÁÁÁ




µA

NOTE: 2. Corresponding to –0.6 dB gain from the line to output RLS in the typical application.

Fre

esc

ale

Se

mic

on

du

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r, I



nc

...

MC33215





LOGARITHMIC AMPLIFIERS AND ENVELOPE DETECTORS


Maximum Sink Current into TSE or RSE ÁÁÁÁÁÁÁÁÁÁ




µA


Maximum Sink Current into TBN and RBN ÁÁÁÁÁÁÁÁÁÁ




µA


Maximum Source Current from TBN or RBN ÁÁÁÁÁÁÁÁÁÁ




µA


Dial Tone Detector Threshold at Vline ÁÁÁÁÁÁÁÁÁÁ


20 ÁÁÁÁÁÁÁÁ


mVrms


Speech Noise Threshold Both Channels ÁÁÁÁÁÁÁÁÁÁ




dB


ATTENUATOR CONTROL


Switching Depth ÁÁÁÁÁÁÁÁÁÁ

46 ÁÁÁÁÁÁÁÁ

50 ÁÁÁÁÁÁÁÁ

54 ÁÁÁÁÁÁÁÁ

dB


Adjustable Range for Switching Depth ÁÁÁÁÁÁÁÁÁÁ

24 ÁÁÁÁÁÁÁÁ


60 ÁÁÁÁÁÁÁÁ

dB


Gain Variation in Idle Mode for Both Channels ÁÁÁÁÁÁÁÁÁÁ


25 ÁÁÁÁÁÁÁÁ


dB


Current Sourced from SWT ÁÁÁÁÁÁÁÁÁÁ


10 ÁÁÁÁÁÁÁÁ

13 ÁÁÁÁÁÁÁÁ

µATx ModeÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁCurrent Sunk into SWT


7.0ÁÁÁÁÁÁÁÁ

10ÁÁÁÁÁÁÁÁ

13ÁÁÁÁÁÁÁÁ

µARx Mode

PIN FUNCTION DESCRIPTION

Pin

N D i iSDIP–42 TQFP–52 Name Description

ÁÁÁÁÁÁÁÁ

1 ÁÁÁÁÁÁÁÁ

47 ÁÁÁÁÁÁÁÁÁÁ

VCC ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Supply Output for Loudspeaker Amplifier and Peripherals

ÁÁÁÁÁÁÁÁ

2 ÁÁÁÁÁÁÁÁ


VLN ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Line Connection Input

ÁÁÁÁÁÁÁÁ

3 ÁÁÁÁÁÁÁÁ


VHF ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Supply Output for Speakerphone Section and Base Microphone

ÁÁÁÁÁÁÁÁ

4 ÁÁÁÁÁÁÁÁ


VMC ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Supply Output for Handset Microphone

ÁÁÁÁÁÁÁÁ



N/C ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Not Connected

ÁÁÁÁÁÁÁÁ




Not Connected

ÁÁÁÁÁÁÁÁ

5 ÁÁÁÁÁÁÁÁ


SLB ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

SLP Buffered Output

ÁÁÁÁÁÁÁÁ

6 ÁÁÁÁÁÁÁÁ


REG ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Regulation of Line Voltage Adjustment

ÁÁÁÁÁÁÁÁ

7 ÁÁÁÁÁÁÁÁ


SLP ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

DC Slope Adjustment

ÁÁÁÁÁÁÁÁ

8 ÁÁÁÁÁÁÁÁ


MFI ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

DTMF Input

ÁÁÁÁÁÁÁÁ

9 ÁÁÁÁÁÁÁÁ


HM1 ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Handset Microphone Input 1

ÁÁÁÁÁÁÁÁ

10 ÁÁÁÁÁÁÁÁ


HM2 ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Handset Microphone Input 2

ÁÁÁÁÁÁÁÁ

11 ÁÁÁÁÁÁÁÁ


BM2 ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Base Microphone Input 2

ÁÁÁÁÁÁÁÁ

12 ÁÁÁÁÁÁÁÁ


BM1 ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Base Microphone Input 1

ÁÁÁÁÁÁÁÁ

13 ÁÁÁÁÁÁÁÁ


VDD ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Supply Input for Speech Part

ÁÁÁÁÁÁÁÁ

14 ÁÁÁÁÁÁÁÁ


TSA ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Transmit Sensitivity Adjustment

ÁÁÁÁÁÁÁÁ

15 ÁÁÁÁÁÁÁÁ


TSE ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Transmit Signal Envelope Timing Adjustment

ÁÁÁÁÁÁÁÁ

16 ÁÁÁÁÁÁÁÁ


TBN ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Transmit Background Noise Envelope Timing Adjustment

17 13 MUT Transmit and Receive Mute Input

ÁÁÁÁÁÁÁÁ




Not Connected

ÁÁÁÁÁÁÁÁ




Not Connected

ÁÁÁÁÁÁÁÁ

18 ÁÁÁÁÁÁÁÁ


SPS ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Speakerphone Select Input

19 17 PRS Privacy Switch Input

ÁÁÁÁÁÁÁÁ

20 ÁÁÁÁÁÁÁÁ


SWT ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Switch–Over Timing Adjustment

21 19 LSM Loudspeaker Mute Input

Fre

esc

ale

Se

mic

on

du

cto

r, I



nc

...

MC33215


PIN FUNCTION DESCRIPTION (continued)

Pin

DescriptionNameSDIP–42 DescriptionNameTQFP–52ÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ

20ÁÁÁÁÁÁÁÁÁÁ

N/CÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Not ConnectedÁÁÁÁÁÁÁÁ

22ÁÁÁÁÁÁÁÁ


RXSÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Receive Amplifier StabilityÁÁÁÁÁÁÁÁ

23ÁÁÁÁÁÁÁÁ


RXOÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Receive Amplifier OutputÁÁÁÁÁÁÁÁ

24ÁÁÁÁÁÁÁÁ


GRXÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Earpiece Amplifier Feedback InputÁÁÁÁÁÁÁÁ

25ÁÁÁÁÁÁÁÁ


RXIÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Receive Amplifier InputÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ




–ÁÁÁÁÁÁÁÁ




26ÁÁÁÁÁÁÁÁ


RBNÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Receive Background Noise Envelope Timing AdjustmentÁÁÁÁÁÁÁÁ

27ÁÁÁÁÁÁÁÁ


RSEÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Receive Signal Envelope Timing AdjustmentÁÁÁÁÁÁÁÁ

28ÁÁÁÁÁÁÁÁ


RSAÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Receive Sensitivity AdjustmentÁÁÁÁÁÁÁÁ

29ÁÁÁÁÁÁÁÁ


RLSÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Receive Output for Loudspeaker AmplifierÁÁÁÁÁÁÁÁ

30ÁÁÁÁÁÁÁÁ


GndÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Small Signal GroundÁÁÁÁÁÁÁÁ

31ÁÁÁÁÁÁÁÁ


AGCÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Line Length AGC AdjustmentÁÁÁÁÁÁÁÁ

32ÁÁÁÁÁÁÁÁ


REFÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Reference Current SetÁÁÁÁÁÁÁÁ

33ÁÁÁÁÁÁÁÁ


SWDÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Switching Depth Adjustment for HandsfreeÁÁÁÁÁÁÁÁ

34ÁÁÁÁÁÁÁÁ


VOLÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Volume Control AdjustmentÁÁÁÁÁÁÁÁ

35ÁÁÁÁÁÁÁÁ


LSIÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Loudspeaker Amplifier InputÁÁÁÁÁÁÁÁ

36ÁÁÁÁÁÁÁÁ


PPLÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Peak–to–Peak Limiter Timing AdjustmentÁÁÁÁÁÁÁÁ

37ÁÁÁÁÁÁÁÁ


BVOÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Bias Voltage for Loudspeaker Amplifier OutputÁÁÁÁÁÁÁÁ

38ÁÁÁÁÁÁÁÁ


LSFÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Loudspeaker Amplifier Feedback InputÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ




–ÁÁÁÁÁÁÁÁ




39ÁÁÁÁÁÁÁÁ


LSBÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Loudspeaker Amplifier Bootstrap OutputÁÁÁÁÁÁÁÁ

40ÁÁÁÁÁÁÁÁ


VLSÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Supply Input for Loudspeaker AmplifierÁÁÁÁÁÁÁÁ

41ÁÁÁÁÁÁÁÁ


LSOÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Loudspeaker Amplifier OutputÁÁÁÁÁÁÁÁ

42ÁÁÁÁÁÁÁÁ


PGDÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Power GroundÁÁÁÁÁÁÁÁ

–ÁÁÁÁÁÁÁÁ



Not Connected

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MC33215


DESCRIPTION OF THE CIRCUIT

Based on the typical application circuit as given inFigure 18, the MC33215 will be described in three parts: linedriver and supplies, handset operation, and handsfreeoperation. The data used refer to typical data of thecharacteristics.

LINE DRIVER AND SUPPLIESThe line driver and supply part performs the ac and dc

telephone line termination and provides the necessarysupply points.

AC Set ImpedanceThe ac set impedance of the telephone as created by the

line driver and its external components can be approximatedwith the equivalent circuit shown in Figure 2.

Figure 2. Equivalent of the AC impedance

Inductor � RREG1 x CREG xRSLP

11

Slope �RSLP

11x �1� RREG1

RREG2�

CVLN10 n

CVDD100 µ

ZVDD620 Zbal

RSLB2.2 k

RREG∞

RREG1360 k

CREG220 n Slope

Inductor

With the component values of the typical application, theinductor calculates as 1.6 H. Therefore, in the audio range of300 Hz to 3400 Hz, the set impedance is mainly determinedby ZVDD. As a demonstration, the impedance matching orBalance Return Loss BRL is shown in Figure 3.

100

40

BRL

(dB)

f, FREQUENCY (Hz)

Figure 3. Balance Return Loss

35

30

25

20

15

10

5.0

01000 10000

The influence of the frequency dependent parasiticcomponents is seen for the lower frequencies (Inductor) andthe higher frequencies (CVLN) by a decreasing BRL value.

DC Set ImpedanceThe line current flowing towards the MC33215 application

is partly consumed by the circuitry connected to VDD whilethe rest flows into Pin VLN. At Pin VLN, the current is split up

into a small part for biasing the internal line drive transistorand into a large part for supplying the speakerphone. Theratio between these two currents is fixed to 1:10. The dc setimpedance or dc setting of the telephone as created by theline driver and its external components can be approximatedwith the equivalent of a zener voltage plus a series resistoraccording to:

Vzener � 0.2 x �1� RREG1RREG2�� 10 µA x RREG1�ILN � Iline – IVDD

Rslope �RSLP

11x �1� RREG1

RREG2�

With:

VLN � Vzener��ILN x Rslope�

If RREG2 is not mounted, the term between the bracketsbecomes equal to 1.

With the values shown in the typical application and underthe assumption that IVDD = 1.0 mA, the above formulas canbe simplified to:

VLN � 3.8 V��Iline – 1.0 mA� x 20�� 3.8 V� �Iline x 20�

In the typical application this leads to a line voltage of 4.2 Vat 20 mA of line current with a slope of 20 Ω. Adding a 1.5 Vvoltage drop for the diode bridge and the interruptor, the dcvoltage at tip–ring will equal 5.7 V.

If the dc mask is to be adapted to a country specificrequirement, this can be done by adjusting the resistorsRREG1 and RREG2, as a result, the zener voltage and theslope are varied. It is not advised to change the resistor RSLPsince this changes many parameters. The influence of RREG1and RREG2 is shown in Figure 4.

Figure 4. Influence of R REG1 and RREG2 on the DC Mask

0

12

VLN

(V)

Iline (mA)

10

8.0

6.0

4.0

2.0

020 40 60 80 100

.

RREG1 = 470 kRREG2 = 220 k

RREG1 = 365 kRREG2 = 220 k

RREG1 = 470 kRREG2 = Infinite

RREG1 = 365 kRREG2 = Infinite

As can be seen in Figure 4, for low line currents below10 mA, the given dc mask relations are no longer valid. Thisis the result of an automatic decrease of the current drawn

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MC33215


from Pin REG by the internal circuit (the 10 µA term in theformulas). This built–in feature drops the line voltage andtherefore enables parallel operation.

The voltage over the line driver has to be limited to 12 V toprotect the device. A zener of 11 V at VLN is therefore themaximum advised.

VDD SupplyThe internal circuitry for the line driver and handset

interface is powered via VDD. This pin may also be used topower peripherals like a dialer or microcontroller. The voltageat VDD is not internally regulated and is a direct result of theline voltage setting and the current consumption at VDDinternally (IVDD) and externally (IPER). It follows that:

VDD � VLN –�IVDD� IPER� x Rset

For correct operation, it must be ensured that VDD isbiased at 1.8 V higher than SLP. This translates to amaximum allowable voltage drop across ZVDD ofVzener – 1.8 V. In the typical application, this results in amaximum allowable current consumption by the peripheralsof 2.0 mA.

VMC SupplyAt VMC, a stabilized voltage of 1.75 V is available for

powering the handset microphone. Due to this stabilizedsupply, microphones with a low supply rejection can be usedwhich reduces system costs. In order to support the paralleloperation of the telephone set, the voltage at VMC will bemaintained even at very low line currents down to 4.0 mA.

Under normal supply conditions of line currents of 20 mAand above, the supply VMC is able to deliver a guaranteedminimum of 1.0 mA. However, for lower line currents, thesupply capability of VMC will decrease.

Figure 5. VMC Under Different Microphone Loads

0

1.8

VMC

(V)

IVMC (mA)

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.00.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Iline = 4.0 mA2.7 k VMC–VHF

Iline = 20 mA

Iline = 4.0 mA

If, during parallel operation, a high current is required fromVMC, a 2.7 k resistor between VMC and VHF can be applied.In Figure 5, the VMC voltage under different microphonecurrents, is shown.

VHF SupplyVHF is a stabilized supply which powers the internal

duplex controller part of the MC33215, and which is alsomeant to power the base microphone or other peripherals.The base microphone however, can also be connected toVMC, which is preferred in case of microphones with a poorsupply rejection. Another possibility is to create an additionalfilter at VHF, like is shown in the typical application. Thesupply capability of VHF is guaranteed as 2.0 mA for linecurrents of 20 mA and greater.

Since in parallel operation not enough line current isavailable to power a loudspeaker and thus having aspeakerphone working, the current internally supplied to VHFis cut around 10 mA of line current to save current for thehandset operated part. A small hysteresis is built in to avoidsystem oscillations.

When the current to VHF is cut, the voltage at VHF willdrop rapidly due to the internal consumption of 1.4 mA andthe consumption of the peripherals. When VHF drops below2.0 V, the device internally switches to the handset mode,neglecting the state of the speakerphone select Pin SPS.

In case an application contains a battery pack or if it ismains supplied, speakerphone operation becomes possibleunder all line current conditions. In order to avoid switch–overto handset operation below the 10 mA, VHF has to besupplied by this additional power source and preferably keptabove 2.4 V.

VCC SupplyAt VCC the major part of the line current is available for

powering the loudspeaker amplifier and peripheral circuitry.This supply pin should be looked at as a current source sincethe voltage on VCC is not stabilized and depends on theinstantaneous line voltage and the current to and consumedfrom VCC.

The maximum portion of the line current which is availableat VCC is given by the following relation:

IVCC ��1011

x �Iline – IVDD�� – IVMC – IVHF This formula is valid when the voltage drop from VLN to

VCC is sufficient for the current splitter to conduct all thiscurrent to VCC. When the drop is not sufficient, the currentsource saturates and the surplus of current is conducted tothe power ground PGD to avoid distortion in the line driver. Infact, when no current is drawn from VCC, the voltage at VCCwill increase until the current splitter is in balance. In Figure 6this behavior is depicted.

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MC33215


A. Maximum Available Current at V CC

Figure 6. Available Current at V CC

0

100

Iline (mA)

0

3.5

CC

VLN

–V

(V

)

Iline (mA)

90

80

70

60

50

40

30

20

10

020 40 60 80 100

3.0

2.5

2.0

1.5

1.0

0.5

020 40 60 80 100

B. Voltage Drop to V CC

IVCC/lline (%)

IVCC(max) (mA)

VCC to VLS

IVCC at 98% ofIVCC(max) IVCC at 50% of

IVCC(max)

VCC Open

mA

AND

%

For instance, at a line current of 20 mA a maximum of15 mA of current is available at VCC. If all this current istaken, VCC will be 1.7 V below VLN. When not all this currentis drawn from VCC, but for instance only 1.0 mA for biasing ofthe loudspeaker amplifier, the voltage at VCC will be 1.2 Vbelow VLN. Although the measurements for Figure 6 aredone with RREG1 = 365 k, the results are also globally validfor other dc settings.

As can be seen from Figure 6, the voltage at VCC is limitedby the voltage at VLN minus 1.0 V. This means that thevoltage at VCC is limited by the external zener at VLN. If it isnecessary to limit the voltage at VCC in order to protectperipheral circuits, a zener from VCC to Gnd can be added. Ifthe supply of the loudspeaker VLS is also connected to VCC,it is advisable that VCC does not exceed 8.0 V.

The high efficiency of the VCC power supply contributesto a high loudspeaker output power at moderate linecurrents. More details on this can be found in the handsfreeoperation paragraph.

HANDSET OPERATIONDuring handset operation, the MC33215 performs the

basic telephone functions for the handset microphone andearpiece. It also enables DTMF transmission.

Handset Microphone AmplifierThe handset microphone is to be capacitively connected

to the circuit via the differential input HM1 and HM2. Themicrophone signal is amplified by the HMIC amplifier andmodulates the line current by the injection of the signal intothe line driver. This transfer from the microphone inputs to theline current is given as 15/(RSLP/11), which makes a totaltransmit voltage gain AHM from the handset microphoneinputs to the line of:

AHM �VlineVHM

� 15RSLP�11

xZline x ZsetZline � Zset

With the typical application and Zline = 600 Ω the transmitgain calculates as 47 dB.

In case an electret microphone is used, it can be suppliedfrom the stabilized microphone supply point VMC of 1.75 Vproperly biased with resistors RHM1 and RHM2. This allowsthe setmaker to use an electret microphone with poor supplyrejection to reduce total system costs. Since the transmit gainAHM is fixed by the advised RSLP = 220 Ω and the constraintsof set impedance and line impedance, the transmit gain is set

by adjusting the sensitivity of the handset microphone byadjusting the resistors RHM1 and RHM2. It is not advised toadjust the gain by including series resistors towards the PinsHM1 and HM2.

A high pass filter is introduced by the coupling capacitorsCHM1 and CHM2 in combination with the input impedance. Alow pass filter can be created by putting capacitors in parallelwith the resistors RHM1 and RHM2.

The transmit noise is measured as –72 dBmp with thehandset microphone inputs loaded with a capacitivelycoupled 200 Ω. In a real life application, the inputs will beloaded with a microphone powered by VMC. Although VMCis a stablized supply voltage, it will contain some noise whichcan be coupled to the handset microphone inputs, especiallywhen a microphone with a poor supply rejection is used. Anadditional RC filter on VMC can improve the noise figure, seealso the base microphone section.

Handset Earpiece AmplifierThe handset earpiece is to be capacitively connected to

the RXO output. Here, the receive signal is available which isamplified from the line via the sidetone network and the Rxand EAR amplifiers. The sidetone network attenuates thereceive signal from the line via the resistor divider composedof RSLB and Zbal, see also the sidetone section. Theattenuation in the typical application by this network equals24.6 dB. Then the signal from the sidetone network ispre–amplified by the amplifier Rx with a typical gain of 6.0 dB.This amplifier also performs the AGC and MUTE functions,see the related paragraphs. Finally, the signal is amplified bythe noninverting voltage amplifier EAR. The overall receivegain ARX from the line to the earpiece output then follows as:

ARX �VRXOVline

� AST x ARXI x �1� RRXORGRX� With: AST = Attenuation of the Sidetone Network

ARXI = Gain of the Pre–Amplifier RxFor the typical application an overall gain from the line to

the earpiece is close to 0 dB.The receive gain can be adjusted by adjusting the resistor

ratio RRXO over RGRX. However, RRXO also sets theconfidence tone level during dialing which leaves RGRX to bechosen freely. A high pass filter is introduced by the couplingcapacitor CRXI together with the input impedance of the input

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MC33215


RXI. A second high pass filtering is introduced by thecombination of CGRX and RGRX. A low pass filter is createdby CRXO and RRXO. The coupling capacitor at the outputRXO is not used for setting a high pass filter but merely for dcdecoupling.

In combination with dynamic ear capsules, the EARamplifier can become unstable due to the highly inductivecharacteristic of some of the capsules. To regain stability, a100 nF capacitor can be connected from RXS to Gnd inthose cases. An additional 10 nF at the RXI input, as shownin the typical application, improves the noise figure of thereceiver stage.

Sidetone CancellationThe line driver and the receiver amplifier of the MC33215

are tied up in a bridge configuration as depicted in Figure 7.This bridge configuration performs the so–called hybridfunction which, in the ideal case, prevents transmitted signalsfrom entering the receive channel.

Figure 7. Sidetone Bridge

VHM x 15

RSLP�11

VLN

Zline//Zset

SLP

RSLP/11

Gnd

Zbal

RSLB Gnd

RXIReceive

Transmit

As can be seen from Figure 7 by inspection, the receiverwill not pick up any transmit signal when the bridge is inbalance, that is to say when:

ZbalRSLB

�

Zline��ZsetRSLP�11

The sidetone suppression is normally measured in anacoustic way. The signal at the earpiece when applying asignal on the microphone is compared with the signal at theearpiece when applying a signal on the line. The suppressiontakes into account the transmit and receive gains set. In factthe sidetone suppression can be given as a purely electricalparameter given by the properties of the sidetone bridgeitself. For the MC33215, this so–called electrical sidetonesuppression ASTE can be given as:

ASTE � 1 –Zbal

RSLBx

RSLP�11

Zline��Zset

Values of –12 dB or better, thus ASTE < 0.25, can easily bereached in this way.

Automatic Gain ControlTo obtain more or less constant signal levels for transmit

and receive regardless of the telephone line length, both thetransmit and receive gain can be varied as a function of linecurrent when the AGC feature is used. The gain reduction asa function of line current, and thus line length, is depicted inFigure 8.

0

0

AGC

(dB)

Iline (mA)

Figure 8. Automatic Gain Control

–1.0

–2.0

–3.0

–4.0

–5.0

–6.010 20 30 40 50 60 70

RAGC = 20 k

RAGC = 30 k

For small line currents, and thus long lines, no gainreduction is applied and thus the transmit and receive gainsare at their maximum. For line currents higher than Istart, thegain is gradually reduced until a line current Istop is reached.This should be the equivalent of a very short line, and thegain reduction equals 6.0 dB. For higher line currents thegain is not reduced further. For the start and stop currents thefollowing relations are valid:

Istop �1

RSLP�11

Istart �1

RSLP�11–

20 µ x RAGCRSLP�11

For the typical application, where RAGC = 30 kΩ, the gainwill start to be reduced at Istart = 20 mA while reaching 6.0 dBof gain reduction at Istop = 50 mA. When AGC is connected toVDD, the AGC function is disabled leading to no gainreduction for any line current. This is also sometimes calledPABX mode.

The automatic gain control takes effect in the HMIC and Rxamplifiers as well as in the BMIC amplifier. In this way theAGC is also active in speakerphone mode, see the handsfreeoperation paragraph.

Privacy and DTMF ModeDuring handset operation a privacy and a DTMF mode can

be entered according the logic Table 1.

Table 1. Logic Table for Handset Mode

Logic Inputs

M d

Amplifiers

SPS MUT PRS Mode HMIC BMIC DTMF Rx RXatt EARÁÁÁÁÁÁÁÁ0

ÁÁÁÁÁÁ1ÁÁÁÁÁÁÁÁ1

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁHandset Normal

ÁÁÁÁÁÁÁÁOn

ÁÁÁÁÁÁOffÁÁÁÁÁÁÁÁOff

ÁÁÁÁÁÁOnÁÁÁÁÁÁÁÁOff

ÁÁÁÁÁÁOnÁÁÁÁ

ÁÁÁÁ0ÁÁÁÁÁÁ1ÁÁÁÁÁÁÁÁ0

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁHandset Privacy

ÁÁÁÁÁÁÁÁOff

ÁÁÁÁÁÁOffÁÁÁÁÁÁÁÁOn

ÁÁÁÁÁÁOnÁÁÁÁÁÁÁÁOff

ÁÁÁÁÁÁOnÁÁÁÁ

ÁÁÁÁ0ÁÁÁÁÁÁ0ÁÁÁÁÁÁÁÁX

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁHandset DTMF

ÁÁÁÁÁÁÁÁOff

ÁÁÁÁÁÁOffÁÁÁÁÁÁÁÁOn

ÁÁÁÁÁÁOffÁÁÁÁÁÁÁÁOff

ÁÁÁÁÁÁOn

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MC33215


Table 2. Logic Table for Handsfree Mode

Logic Inputs

M d

Amplifiers

SPS MUT PRS Mode HMIC BMIC DTMF Rx RXatt EARÁÁÁÁÁÁÁÁ

1ÁÁÁÁÁÁ

1ÁÁÁÁÁÁÁÁ

1ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Handsfree NormalÁÁÁÁÁÁÁÁ

OffÁÁÁÁÁÁ

OnÁÁÁÁÁÁÁÁ

OffÁÁÁÁÁÁ

OnÁÁÁÁÁÁÁÁ

OnÁÁÁÁÁÁ

OffÁÁÁÁÁÁÁÁ

1ÁÁÁÁÁÁ

1ÁÁÁÁÁÁÁÁ

0ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Handsfree PrivacyÁÁÁÁÁÁÁÁ

OffÁÁÁÁÁÁ

OffÁÁÁÁÁÁÁÁ

OnÁÁÁÁÁÁ

OnÁÁÁÁÁÁÁÁ

OnÁÁÁÁÁÁ

OffÁÁÁÁÁÁÁÁ

1ÁÁÁÁÁÁ

0ÁÁÁÁÁÁÁÁ

XÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Handsfree DTMFÁÁÁÁÁÁÁÁ

OffÁÁÁÁÁÁ

OffÁÁÁÁÁÁÁÁ

OnÁÁÁÁÁÁ

OffÁÁÁÁÁÁÁÁ

OnÁÁÁÁÁÁ

Off

By applying a logic 0 to Pin MUT, the DTMF mode isentered where the DTMF amplifier is enabled and where theRx amplifier is muted. A DTMF signal can be sent to the linevia the MFI input for which the gain ADTMF is given as:

ADTMF �VlineVMFI

�3.75

RSLP�11x

Zline x ZsetZline� Zset

In the typical application, the gain equals 35 dB. TheDTMF gain can be controlled by a resistor divider at the inputMFI as shown in the typical application. The signal has to becapacitively coupled to the input via CMFI which creates ahigh pass filter with the input impedance. The line lengthAGC has no effect on the DTMF gains.

The signal applied to the MFI input is made audible at theearpiece output for confidence tone. The signal is internallyapplied to the GRX pin where it is amplified via the EARamplifier which is used as a current to voltage amplifier. Thegain is therefore proportional to the feedback resistor RRXO.For RRXO = 180 kΩ the gain equals 6.0 dB. The confidencetone is also audible at the loudspeaker output when theloudspeaker amplifier is activated, see speakerphoneoperation.

By applying a logic 0 to Pin PRS, the MC33215 entersprivacy mode. In this mode, both handset and handsfreemicrophone amplifiers are muted while the DTMF amplifier isenabled. Through the MFI input, a signal, for example musicon hold, can be sent to the line. In the same way, the MFIinput can also be used to couple in signals from, for instance,an answering machine.

HANDSFREE OPERATIONHandsfree operation, including DTMF and Privacy modes,

can be performed by making Pin SPS high according Table 2.The handset amplifiers will be switched off while the baseamplifiers will be activated. The MC33215 performs all thenecessary functions, such as signal monitoring andswitch–over, under supervision of the duplex controller.

With the MC33215 also a group listening–in applicationcan be built. For more information on this subject please referto application note AN1574.

Base Microphone AmplifierThe base microphone can be capacitively connected to

the circuit via the differential input BM1 and BM2. The setupis identical to the one for the handset microphone amplifier.The total transmit voltage gain ABM from the basemicrophone inputs to the line is:

ABM�VlineVBM

�37.5

RSLP�11x

Zline x ZsetZline� Zset

With the typical application and Zline = 600 Ω the transmitgain calculates as 55 dB.

The electret base microphone can be supplied directlyfrom VHF but it is advised to use an additional RC filter toobtain a stable supply point, as shown in the typicalapplication. The microphone can also be supplied by VMC.The transmit gain is set by adjusting the sensitivity of thebase microphone by adjusting the resistors RBM1 and RBM2.It is not advised to adjust the gain by including seriesresistors towards the Pins BM1 and BM2.

A high pass filter is introduced by the coupling capacitorsCBM1 and CBM2 in combination with the input impedance. Alow pass filter can be created by putting capacitors in parallelwith the resistors RBM1 and RBM2.

Loudspeaker AmplifierThe loudspeaker amplifier of the MC33215 has three major

benefits over most of the existing speakerphone loudspeakeramplifiers: it can be supplied and used in a telephone linepowered application but also stand alone, it has an all NPNbootstrap output stage which provides maximum outputswing under any supply condition, and it includes apeak–to–peak limiter to limit the distortion at the output.

The loudspeaker amplifier is powered at Pin VLS. Intelephone line powered applications, this pin should beconnected to VCC where most of the line current is available,see the VCC supply paragraph. In an application where anexternal power supply is used, VLS and thus the loudspeakeramplifier can be powered separately from the rest of thecircuit. The amplifier is grounded to PGD, which is the circuitspower ground shared by both the loudspeaker amplifier andthe current splitter of the VCC supply. Half the supply voltageof VLS is at BVO, filtered with a capacitor to VLS. Thisvoltage is used as the reference for the output amplifier.

The receive signal present at RLS can be capacitivelycoupled to LSI via the resistor RLSI. The overall gain fromRLS to LSO follows as:

ALS �VLSOVRLS

� –RLSFRLSI

x 4.0

In the typical application this leads to a loudspeaker gainALS of 26 dB. The above formula follows from the fact that theoverall amplifier architecture from RLS to LSO can be lookedat as an inverting voltage amplifier with an internal currentgain from LSI to LSF of 4. The input LSI is a signal currentsumming node which allows other signals to be applied here.

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MC33215


Figure 9. Loudspeaker Output Stage

VLS

Loudspeaker

CLSO

LSB

LSO

PGD

T2

T1

1.5 VLS

VLS

0.5 VLS

VLS

0.5 VLS

0

0.5 VLS

0

–0.5 VLS

VLS

Figure 10. Loudspeaker Amplifier Output Power with External Supply

2.0

140

PLS

P (m

W)

VLS (V)

2.0

300

RLSP = 25 Ω

RLSP = 50 Ω

RLSP = 25 Ω

RLSP = 50 ΩPLS

P (m

W)

VLS (V)

120 250

100200

80150

60

100

20 50

0 03.0 4.0 3.05.0 4.06.0 5.07.0 6.08.0 7.0 8.0

40

A. Peak–to–Peak Limiter Active B. Peak–to–Peak Limiter Disabled

The total gain from the telephone line to the loudspeakeroutput includes, besides the loudspeaker amplifier gain, alsothe attenuation of the sidetone network and the internal gainfrom RXI to RLS. When in receive mode, see under duplexcontroller, the gain from RXI to RLS is maximum and equals24 dB at maximum volume setting. The attenuation of thesidetone network in the typical application equals 24.6 dBwhich makes an overall gain from line to loudspeaker of25.4 dB. Due to the influence of the line length AGC on the Rxamplifier, the gain will be reduced for higher line currents.

The output stage of the MC33215 is a modified all NPNbootstrap stage which ensures maximum output swing underall supply conditions. The major advantage of this type ofoutput stage over a standard rail–to–rail output is the higherstability. The principle of the bootstrap output stage isexplained with the aid of Figure 9.

The output LSO is biased at half the supply VLS while thefiltering of the loudspeaker with the big capacitor CLSOrequires that LSB is biased at VLS. In fact, because of thefiltering, LSB is kept at VLS/2 above the LSO output even ifLSO contains an ac signal. This allows the output transistor

T2 to be supplied for output signals with positive excursionsup to VLS without distorting the output signal. The resultingac signal over the loudspeaker will equal the signal at LSO.As an indication of the high performance of this type ofamplifier, in Figure 10, the output power of the loudspeakeramplifier as a function of supply voltage is depicted for 25 Ωand 50 Ω loads with both the peak–to–peak limiter active anddisabled. As can be seen, in case the peak–to–peak limiter isdisabled, the output power is roughly increased with 6.0 dB,this at the cost of increased distortion levels up to 30%.

In a telephone line powered application, the loudspeakeramplifier output power is limited not only by the supplyvoltage but also by the telephone line current. This meansthat in telephones the use of 25 Ω or 50 Ω speakers ispreferred over the use of the cheaper 8.0 Ω types. Figure 11gives the output power into the loudspeaker for a linepowered application and two different dc settings with thepeak–to–peak limiter active. In case the peak–to–peak limiteris disabled the output power will be increased for the higherline currents up to 6.0 dB.

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MC33215


0

100P L

SP (m

W)

Iline (mA)

RREG1 = 365 kRREG2 = 220 kRLSP = 25 Ω

Figure 11. Loudspeaker Amplifier OutputPower when Line Powered

RREG1 = 365 kRREG2 = 220 kRLSP = 50 Ω

RREG1 = 365 kRREG2 = InfiniteRLSP = 50 Ω

RREG1 = 365 kRREG2 = InfiniteRLSP = 25 Ω

20 40 60 80 100

90

80

70

60

50

40

30

20

10

0

The quality of the audio output of the loudspeaker amplifieris mainly determined by the distortion level. To keep highquality under difficult supply conditions, the MC33215incorporates a peak–to–peak limiter. The peak–to–peaklimiter will detect when the output stage gets close to itsmaximum output swing and will then reduce the gain from LSIto LSF. The attack and release of the limiter is regulated bythe CPPL capacitor. Figure 12 depicts the limiter’s attackbehavior with CPPL = 100 nF. The release time is given as3 x CPPL x RPPL. In the typical application this leads to arelease time of 300 ms.

Figure 12. Peak–to–Peak Limiter Dynamic Behavior

0

0.5

V/D

IV

t, TIME (ms)

VLSO

VPPL

Vin

1.0 2.0 3.0 4.0 5.0 6.0

Figure 12 clearly shows that due to the action of thepeak–to–peak limiter, the output swing and thus the outputpower is reduced with respect to the maximum possible asalready indicated in Figure 10. The peak–to–peak limiter canbe disabled by connecting the PPL pin to ground.

On top of the peak–to–peak limiter, the MC33215incorporates a supply limiter, which reduces the gain rapidlywhen the supply voltage VLS drops too much. This willavoid malfunctioning of the amplifier and unwantedoscillations. The voltage drop is detected via the BVO inputand for that reason the CBVO has to be connected to VLSand not to Gnd.

The amplifier can be activated by making Pin LSM high. Inthe typical application this pin is connected to SPS, whichactivates the loudspeaker amplifier automatically when thespeakerphone mode is entered. When LSM is made low, the

loudspeaker amplifier is muted which is needed for correcthandset operation.

The volume of the loudspeaker signal can be varied via apotentiometer at VOL. A fixed current of 10 µA is runningthrough the potentiometer and the resulting voltage at VOLis a measure for the gain reduction. The relation betweenthe voltage at VOL and the obtained gain reduction is givenin Figure 13.

0

0

dALS

P (d

B)

VVOL (mV), dALSP (dB)

Figure 13. Volume Reduction

100 200 300 400 500

–5.0

–10

–15

–20

–25

–35

–30

–40

It can be seen from Figure 13 that a linear variation ofRVOL will give a logarithmic gain reduction which adaptsbetter to the human ear than a linear gain reduction.

During DTMF dialing, see Table 2, a confidence tone isaudible at the loudspeaker of which the level is proportionalto the feedback resistor RLSF only. At RLSF = 180 kΩ the gainfrom MFI to LSO equals 28.5 dB.

Half Duplex ControllerTo avoid howling during speakerphone operation, a half

duplex controller is incorporated. By monitoring the signals inboth the transmit and receive channel the duplex controllerwill reduce the gain in the channel containing the smallestsignal. A typical gain reduction will be between 40 dB and52 dB depending on the setting, see below. In case of equalsignal levels or by detection of noise only, the circuit goes intoidle mode. In this mode the gain reduction in both channels ishalfway, leading to 20 dB to 26 dB of reduction.

In a speakerphone built around the MC33215, followingthe signal path from base microphone to the line and viasidetone, loudspeaker and acoustic coupling back to themicrophone, the loop gain can be expressed as a sum of thegains of the different stages. However, since the transmit andreceive gains are dependent on AGC and the sidetonesuppression is dependent on matching with the different lineswe are mostly interested by the maximum possible loop gainALOOP(max). It follows:

ALOOP(max) = ABMRX(max) + ARXBM(max) – ASWD (dB)

With: ABMRX(max) = Maximum gain from BM1 and BM2 toRXI as a function of line length AGC and lineimpedance matching

ARXBM(max) = Maximum gain from RXI to BM1 andBM2 as a function of line length AGC and acousticcoupling

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MC33215


ASWD = Switching depth as performed in theattenuators

To avoid howling, the maximum possible loop gain shouldbe below 0 dB and preferably below –10 dB for comfort. In apractical telephone design, both the ABMRX(max) and theARXBM(max) will be less than 20 dB thus a switching depth of50 dB will give a loop gain of less than –10 dB. An optimizedsidetone network is of high importance for handsfreeoperation. The better the network matches with thetelephone line the less local feedback and the smaller theswitching range can be.

The amount of gain reduction ASWD obtained by theduplex controller is set via resistor RSWD according:

ASWD � 20 log�3.6 x RSWD

RREF�

2

(dB)

In the typical application the gain reduction will be 50 dB.

To compare the transmit and receive signals with eachother, they have to be monitored. This is done by making asignal envelope and a background noise envelope via theCTSE, CTBN capacitors for the transmit channel and via theCRSE, CRBN capacitors for the receive channel. In Figure 14,a schematic behavior of the envelopes is depicted which isequal for both transmit and receive.

The voltage signal at the input is first transferred to acurrent via the sensitivity adjust network. Then this current isled through a diode which gives a logarithmic compression involtage. It is this voltage from which the signal envelope iscreated by means of asymmetric charge and discharge of thesignal envelope capacitor. The noise envelope voltage thenfollows in a similar way. Based on the envelope levels, theMC33215 will switch to transmit, receive or idle modefollowing Table 3. The fact that in receive mode the signal onthe base microphone is greater than it is in case of transmit

mode, due to the coupling of the high loudspeaker signal, isautomatically taken into account.

In the table, two particulars can be found. At first, the setwill go to idle mode if the signals are not at least 4.5 dBgreater then the noise floor, which calculates as a 13 mVvoltage difference in envelopes. This avoids continuousswitching over between the modes under slight variations ofthe background noise due to, for instance, typing on akeyboard. Second, a dial tone detector threshold isimplemented to avoid that the set goes to idle mode inpresence of a continuous strong receive signal like a dialtone. The dial tone detector threshold is proportional to theRRSA resistor. In the typical application with RRSA = 3.3 kΩ,the threshold is at 1.26 mVrms at the input RXI or 20 mVrmsat the line. Line length AGC is of influence on the dial tonedetector threshold, increasing the level depending on the linecurrent with a maximum of 6.0 dB.

In order to perform a correct comparison between thesignal strengths, the sensitivity of the envelope detectors canbe adjusted via the resistors connected to TSA and RSA.Based on the above, and on the fact that there is an effectivegain of 20 dB in the transmit monitor, it can be derived that forstable operation the following two relations are valid:

20 log�RTSA� � 20 log�RRSA� – ABMRX(max)� 20 (dB)

20 log�RTSA� � 20 log�RRSA� – ARXBM(max)– ASW� 20 (dB)

By measuring the gains and choosing the RRSA, the limitsfor RTSA follow. The choice for the sensitivity resistors is notcompletely free. The logarithmic compressors and theamplifier stages have a certain range of operation and, on thereceive side, the choice for RRSA is given by the desired dialtone detector threshold. Figure 15 indicates the availabledynamic range for the selected value of the sensitivityresistors.

Figure 14. Signal and Noise Envelopes

MicrophoneInput Signal

1.8 VInternal

TSA

RTSA

CTSA

TSECTSE CTBN

TBN

VHF VHF

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MC33215


Table 3. Logic Table for Switch–Over

TSE > RSE TSE > TBN + 13 mV RSE > VDDT RSE > RBN + 13 mV ModeÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

1ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

1ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

XÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

XÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

TransmitÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ





IdleÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ





ReceiveÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ





ReceiveÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ





Idle

The resistors for the sensitivity setting have to be coupledcapacitively to the pins for dc decoupling, and also to createa high pass filter to suppress low frequent background noiseslike footsteps and 50 Hz.

The switch–over timing is performed by charging anddischarging the CSWT capacitor. The switch–over fromtransmit to receive or vice versa is fast, on the order ofmilliseconds, and is proportional to the value of CSWT. Theswitch–over to idle mode is slow, in the order of a fewseconds, and is proportional to the product of the values ofRSWT and CSWT. Figure 16 depicts a typical switch–overbehavior when applying transmit and receive stimuli.

The electrical characteristics and the behavior of theMC33215 are not the only factor in designing a handsfreespeakerphone. During the design the acoustics have to betaken into account from the beginning. The choice of thetransducers and the design of the cabinet are of greatinfluence on the speakerphone performance. Also, toachieve a proper handsfree operation, the fine tuning of thecomponents around the duplex controller have to be donewith the final choice of the cabinet and the transducers.

Figure 15. Compression Range of the Signal Monitors

100

100.0E–3

V RXI

(Vrm

s)

RRSA (Ω)

100

100.0E–3

RTSA (Ω)

A. Receive Monitor B. Transmit Monitor

Upper Limit ofCompression

Lower Limit ofCompression

Upper Limit ofCompression

Lower Limit ofCompression V B

M1(

Vrm

s)

1000 100010000 10000100000 100000

10.0E–310.0E–3

1.0E–3

1.0E–3100.0E–6

10.0E–6 100.0E–6

Dial ToneThreshold

Figure 16. Switch–Over Behavior

Receive

Transmit

SWT

VMC – 0.5

VMC + 0.5

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MC33215


VLSP

Figure 17. Test Circuit

Supply Supply1:10

VDD

VHM

VBM

VHF

VLS V

V

V

V

HM1

HM2

BM1

BM2

TSA

TSE

TBN

AGC

REF

SWD

VOL

RLS

BVO

VLS

LSB

LSO

PGD

LSF

Tx Log–Ampand

EnvelopeDetectors

AnalogControlBlock

PeakLimiter

AttenuatorControl

Tx Attenuator

Rx Attenuator Rx

EARLSP

BMIC

HMIC

VDD VLN

VRLS

GndVMC

VHF

VCC

SLB

SLP

MFI

SPS

MUT

PRS

LSM

SWT

RBN

RSE

RSA

RXI

RXO

GRX

RXSLSIPPL

Rx Log–Ampand Envelope

Detectors

LogicControlBlock

DTMF

Driver1x

MHM

MBM

MDF

MRX

MRA

MEAR

AGC

AGC

AGC

MRA

MHM

MBM MDF

MEAR

AGC

REG

MRX

RREG360 k

IlineVac

Vline

Zbal33 k

RSLB2.2 k

ZVDD620 600

0.2 V

CREG220 n

CVDD100 µ

CHM133 n

CHM233 nCBM133 n

CBM233 n

CTSA470 n

CTSE330 n

CTBN4.7 µ

RTSA2.2 k

RAGC30 kRREF20 k

RSWD100 k

RVOL47 k

CBVO220 n

CLSO47 µRLSO180 k

25

CLSI47 n

RLSI36 k

VLSI

RGRX24 k

RRXO180 k

CGRX47 n

VEAR

VRXI

CEAR10 µ

VHF

CRXS100 n

VMF

VSPS

VMUT

VPRS

VLSM

VSWT

CRXI47 n

RRSA3.3 k

CRSA470 n

CRSE330 n

CRBN4.7 µ

CMF147 n

RSLP220

CVCC470 µ

CVHF47 µ

CVMC10 µ

RPPL1.0 M

CPPL100 n

MC33215

S12

1

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MC33215


Figure 18. Typical Application

Supply Supply1:10

VDD

VHF

HM1

HM2

BM1

BM2

TSA

TSE

TBN

AGC

REF

SWD

VOL

RLS

BVO

VLS

LSB

LSO

PGD

LSF

Tx Log–Ampand Envelope

Detectors

AnalogControlBlock

Peak Limiter

AttenuatorControl

Rx Attenuator Rx

EARLSP

BMIC

HMIC

VDD VLNGnd

VMC

VHF

VCC

SLB

SLP

MFI

SPS

MUT

PRS

LSM

SWT

RBN

RSE

RSA

RXI

RXO

GRX

RXSLSIPPL

Rx Log–Ampand Envelope

Detectors

Logic ControlBlock

DTMF

Driver1x

MHM

MBM

MDF

MRX

MRA

MEAR

AGC

AGC

AGC

MRA

MHM

MBM MDF

MEAR

AGC

REG

MRX

RREG1365 k Zbal

33 k

RSLB2.2 k

ZVDD620

0.2 V

CREG220 n

CVDD100 µ

CHM133 n

CHM233 n

CBM133 n

CBM233 n

CTSA1.0 µF

CTSE330 n

CTBN4.7 µ

RTSA470

RAGC30 k

RREF20 k

RSWD100 k

RVOL50 k

CBVO220 n

CLSO47 µ

RLSO180 k

RGRX24 k

RRXO180 k

CGRX47 n

150 Ω

CEAR10 µ

VHF

CRXS100 n

CRXI33 n

RRSA3.3 k

CRSA470 n

CRSE330 n

CRBN4.7 µ

CMF147 n

RSLP220

CVCC470 µ

CVHF47 µ

CVMC10 µ

RPPL1.0 M

CPPL100 n

MC33215VMC

VHF

VCC

25 Ω

CRLS33 n

RHM11.0 k

RBM21.0 k

RHM21.0 k

Dialer orMicrocontroller

Tx Attenuator

SpeakerphoneButton

PrivacyButton

Ring

Tip

T2

T1

Z110 V

VDD

HookSwitch

1

4

7

*

2

5

8

0

3

6

9

#

RBM11.0 k

CSWT100 n

1.0 k

10 µF

RSWT2.2 M

VMC

0.01

RLSI36 k

RREG2

10 n

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MC33215


FB SUFFIXPLASTIC PACKAGE

CASE 848B–04(TQFP–52)ISSUE C

OUTLINE DIMENSIONS

NOTES:1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.2. CONTROLLING DIMENSION: MILLIMETER.3. DATUM PLANE –H– IS LOCATED AT BOTTOM OF

LEAD AND IS COINCIDENT WITH THE LEAD WHERETHE LEAD EXITS THE PLASTIC BODY AT THEBOTTOM OF THE PARTING LINE.

4. DATUMS –A–, –B– AND –D– TO BE DETERMINED ATDATUM PLANE –H–.

5. DIMENSIONS S AND V TO BE DETERMINED ATSEATING PLANE –C–.

6. DIMENSIONS A AND B DO NOT INCLUDE MOLDPROTRUSION. ALLOWABLE PROTRUSION IS 0.25(0.010) PER SIDE. DIMENSIONS A AND B DOINCLUDE MOLD MISMATCH AND ARE DETERMINEDAT DATUM PLANE –H–.

7. DIMENSION D DOES NOT INCLUDE DAMBARPROTRUSION. ALLOWABLE DAMBAR PROTRUSIONSHALL BE 0.08 (0.003) TOTAL IN EXCESS OF THE DDIMENSION AT MAXIMUM MATERIAL CONDITION.DAMBAR CANNOT BE LOCATED ON THE LOWERRADIUS OR THE FOOT.

DETAIL A

L

39

40 26

27

1

52 14

13

L

–A–

B

V

SA–BM0.20 (0.008) D SH

A–B0.05 (0.002)

SA–BM0.20 (0.008) D SC

–D–B V

–B–

SA–

BM

0.20

(0.0

08)

DS

H

A–B

0.05

(0.0

02)

SA–

BM

0.20

(0.0

08)

DS

C

–H–

0.10 (0.004)–C– SEATING

PLANE

DATUMPLANE

MGH

EC M

�

�

DETAIL C

U�

Q�

XW

KT

R

DETAIL C

DIM MIN MAX MIN MAXINCHESMILLIMETERS

A 9.90 10.10 0.390 0.398B 9.90 10.10 0.390 0.398C 2.10 2.45 0.083 0.096D 0.22 0.38 0.009 0.015E 2.00 2.10 0.079 0.083F 0.22 0.33 0.009 0.013G 0.65 BSC 0.026 BSCH ––– 0.25 ––– 0.010J 0.13 0.23 0.005 0.009K 0.65 0.95 0.026 0.037L 7.80 REF 0.307 REFM 5 10 5 10 N 0.13 0.17 0.005 0.007Q 0 7 0 7 R 0.13 0.30 0.005 0.012S 12.95 13.45 0.510 0.530T 0.13 ––– 0.005 –––U 0 ––– 0 –––V 12.95 13.45 0.510 0.530W 0.35 0.45 0.014 0.018X 1.6 REF 0.063 REF

� � � �

� � � �

� �

B

B

DETAIL A

–A–, –B–, –D–

J N

D

F

BASE METAL

SECTION B–B

SA–BM0.02 (0.008) D SC

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MC33215


B SUFFIXPLASTIC PACKAGE

CASE 858–01(SDIP–42)ISSUE O

OUTLINE DIMENSIONS

–A–

1 21

42 22

–B–

SEATINGPLANE

–T–

SAM0.25 (0.010) T SBM0.25 (0.010) T

L

H

MJ 42 PLD 42 PL

F GN

K

C

NOTES:1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.2. CONTROLLING DIMENSION: INCH.3. DIMENSION L TO CENTER OF LEAD WHEN

FORMED PARALLEL.4. DIMENSIONS A AND B DO NOT INCLUDE MOLD

FLASH. MAXIMUM MOLD FLASH 0.25 (0.010).

DIM MIN MAX MIN MAXMILLIMETERSINCHES

A 1.435 1.465 36.45 37.21B 0.540 0.560 13.72 14.22C 0.155 0.200 3.94 5.08D 0.014 0.022 0.36 0.56F 0.032 0.046 0.81 1.17G 0.070 BSC 1.778 BSCH 0.300 BSC 7.62 BSCJ 0.0

NXP Semiconductors | Automotive, Security, IoT · MC33215 4 MOTOROLA ANALOG IC DEVICE DATA...

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