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Transcript of Applications Engineering. ON Semiconductor Page 2 Doing what we said we would do… or Why customers...
Applications
Engineering
ON Semiconductor
Page 2
Doing what we said we would do…
or
Why customers come to us first...
ON Semiconductor
Page 3
Design Support Button…click here
ON Semiconductor
Page 4
Design Support Button…click here
ON Semiconductor
Page 5
Stability in High Speed LDO Regulators An overview of the design relating to low drop out (LDO) regulators.
Design guidelines given for the selection of components based on performance and stability requirements.
Typical questions that generally need or get asked:
What are my input and output requirements?
Do I have transient response and magnitude requirements?
Can I use a regulator or do I need a controller?
What do I need for output capacitors?
If my regulator is oscillating, what do I change to stop it?
My regulator response is slow, so how do I speed it up without causing it to oscillate?
The following slides introduce the different componentsand block diagrams for LDO regulators.
ON Semiconductor
Page 6
Block diagram showing dual LDO controller.
Startup, Over current, and Shutdown functions.
Band Gap reference for setting DC output voltage.
Error Amplifier for controlling external N-channel FET.
Second channel FET turn on for shorting input to output.
Example LDO Controller Block Diagram
MC33567 Dual LDO Controller
ON Semiconductor
Page 7
LDO Regulator Block Diagram
Error Amplifier
Feedback Divider
Output Driver & Load
A(s)-
+Reference Input Supply
Output
Driver
Load
B(s)
C(s)
RV
1V
OV2V
ON Semiconductor
Page 8
LDO Regulator Schematic
FeedbackDivider
Driver
OutputCapacitor
Load
Error Amp
Reference Input
OV
RV
2V
Circuit1
Project 1
tod
AJun 10, 2000
0001 1.0
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Title:
Designed by:
Checked by:
Approved by:
SizeDate
Document N Revision
Sheet of
3 4 5 6 7 8
B
C
D
E
F
G
U1
Vref
Ro Q1
VCC
Co
Rs
R1
R2
CbCaRl
1V
LDO Controller
ON Semiconductor
Page 9
Simplified Block Diagram and Transfer Function
D(s)N(s)
A
C(s)B(s)A(s)1
1
1C(s)1
VV
H(s) VR
O
AC
DC
or 1R2R1
1C(s)1
AV
A(s) B(s)
C(s)
+
-
RO VH(s)V 1V
2V
RV
ON Semiconductor
Page 10
Error Amplifier Detail - A(s)
1ωoω - dominant error amp pole
- secondary error amp pole
oA - error amp open loop gain
aω
1ωs
1sω
1ωs1ω
sA
A(s)1
a
1o
o
- error amp gain bandwidth
Open loop gain greater than 60dB (for less than 0.1% DC output error).
Dominant pole usually set for device, although some devices allow adjusting via compensation pin.
Gain bandwidth usually specified:
Solve for gain bandwidth pole:
Error amp designed to have secondary pole greater than gain bandwidth and usually NOT specified. If not, let:
For stability analysis, assume frequency range:
ooa fA2πω
oo fA
a1 ωω
1o ωωω
Error Amplifier
A(s)-
+
RV
1V
2V)V-(VA(s)V 2R1
ON Semiconductor
Page 11
Feedback Divider Detail - C(s)
Tba
VRTaO1b
V
2
RCCs1AVRsCVRsC1
A1
V
baT RRR 2
1V
RR
1A
Want to design divider for DC gain of Av and AC gain of 1.
Want V1 independent on reference input, Vr.
Need AC gain of 1 for frequencies greater than low frequency pole of error amp.
LDO controller with fixed output voltage has divider built-in and optimized.
If adding to existing internal divider, follow same guidelines.
Use following design guidelines to obtain these result.
Circuit1
Project 1
tod
AJun 11, 2000
0001 1.0
1 1
Title:
Designed by:
Checked by:
Approved by:
SizeDate
Document N Revision
Sheet of
3 4 5 6 7 8
C
D
E
F
G
R1
Cb
Ca R2
OV2V
RV
ON Semiconductor
Page 12
Feedback Divider Detail - C(s) - Continued
Divider Design Guidelines:
aa
V1
C10ωA
R 1AR
RV
12
2ab
Rω100
C DCR
OV
VV
A
1R
VA
aC
OVRV
bC2R
aω
- output voltage (known).- reference voltage (known).- DC gain (solve for).- gain bandwidth (from error amp analysis).- error amp input capacitance (use 10pf if not specified).- first divider resistor (solve for).- second divider resistor (solve for).- divider compensation capacitor (solve for).
Final solution for divider transfer function - C(s):
O2 VC(s)V )()( ACDC 1A1
C(s)V
ON Semiconductor
Page 13
Circuit1
Project 1
tod
AJun 11, 2000
0001 1.0
1 1
Designed by:
Checked by:
Approved by:
SizeDate
Document N Revision
Sheet of
6 7 8
C
D
E
F
G
gm
Cgd
Cgs
Rl
Rs
Co
VCC
Ro
Output Driver and Load Detail - B(s)
1V
OV
OutputCapacitor
Load
Driver
Error AmpOutput
1ωβ
Rg1
1ω1
sRg
1β
ωω1
s
1ωs
B(s)
fsmcsmfc
2
c
1O VB(s)V
osc
CR1
ω
oi
fRC
1ω
gdgsi CCC gdgs
gd
CCC
β
Transfer function for B(s) shown mainly for
reference.
Too complicated to deal with directly.
Will develop design guidelines combining
this with other functions to develop overall
closed loop transfer function.
ON Semiconductor
Page 14
1ω1
ω1
sωβ
Rg1
1ω1
ωs
ωωs
Rg1
βωωω
sωβ
Rg1
1ω1
ωωs
Rg1
βωωωω
s
D(s)
cafsmca
2
a1
2
smfca
3
fsmca1
3
smfca1
4
LDO Closed Loop Transfer Function - H(s)Combining A(s), B(s), and C(s) into the expression for H(s) yields the following, which is ONLY shown for reference. AC1,A
D(s)N(s)
D(s)N(s)
AH(s) VV
The expression for H(s) contains 4 poles and one zero.
It is far too complicated to work from directly.
Stable response requires poles to be in left hand plane.
Analyze pole locations in terms of circuit parameters to make poles be critically or over-damped (no gain peaking in closed loop response).
1ωs
N(s)c
ON Semiconductor
Page 15
LDO Closed Loop Transfer Function - H(s) - Continued
pacso
ω1
ω1
5ω1
RC
ma
ps
m
p
a g1
ωω3
Rg1
ω3ω
120
1
asmp ωRg1
ω1
τ
LDO Regulator Stability Design Guidelines:
1
f1p
ω1
ω1
ω
sR
fω
mg
pω1ω
τoC
- secondary pole for open loop (solve for).- error amp second pole (known or assumed).- driver pole frequency (if driver built in, let ).- gain bandwidth (from error amp analysis).- maximum driver transconductance gain (if driver built in, then is the output impedance of the regulator).- ESR resistance of output capacitor (solve for).- output capacitor (solve for).- overall loop response time (solve for).
aω1p ωω
mg1
ON Semiconductor
Page 16
LDO Closed Loop Stability Analysis Conclusion
Following design guidelines for voltage divider and stability will yield stable LDO regulator.
Design can be optimized for speed with stable operation.
Little or no overshoot ringing for output transient currents.
Design guidelines can be used in reverse to find error amp gain bandwidth if output capacitor and ESR given.
Guidelines show designer which parameters to change to improve stability and/or loop response time for design and/or actual circuits.
Guidelines help designer to select proper controller/driver for application.
No need to solve for poles/zeros or graphically analyze Bode plots for unity gain phase margins.
All conditional guidelines must be met for stability.
Guidelines do not guarantee perfect operation due to unknown parasitics and unknowns.
Still need to simulate and prototype final design.
Following is a design example demonstrating use of guidelines.
ON Semiconductor
Page 17
Example Design using GuidelinesExample LDO regulator design
demonstrating design guidelines.
Following graphs show closed loop
response for changes in circuit.
Circuit at left shows components
used for examples.
Design guidelines valid for other
circuit configurations as well.
These include PFET controllers and
bipolar (NPN and PNP).
Output stability necessary for steady
state and transient output currents.
Circuit parameters:MC33567 - 5MHz gain bandwidth 50 ohm output impedance Optimized internal dividerMTD3055 - 7 mhos transconductance gain 2200 pf input capacitanceLoad - 0.9A (2 ohms)
+
-InternalDivider
Error Amp
1.25V Ref
1.8VOutput
LoadOutput Cap
1/2-MC33567
LDO Controller
MTD3055NFET
3.3V
GndGnd
12V
ON Semiconductor
Page 18
Frequency Response Analysis
ON Semiconductor
Page 19
Changing the ESR (Rs) of the output capacitor beyond the recommended upper and lower limits tends towards instability (gain peaking).
Making the ESR larger speeds up the closed loop response but may increase the magnitude of the initial transient response due to fast changes in output current.
Waveform for varying ESR of output capacitor.
Rs = 30 milliohms appears optimal.(Co = 10,000uF).
ON Semiconductor
Page 20
Waveform for varying output capacitance.
Output capacitance less than lower limit tends towards instability (gain peaking).
Output capacitance greater than lower limit yield same result (choose type and value to meet ESR requirements).
Co > 100uF yields same response.(Rs = 30 milliohms)
ON Semiconductor
Page 21
Waveform for changing output driver - gm and Ci.
System optimized for using MTD3055.
Changing output driver FET can impact loop stability (as shown for this example).
If drivers need to be interchangeable, design for higher gain device (gm) and others will be stable (although loop will be slower).
MTD3055: gm = 7, Ci = 2200pf
MTD3302: gm = 28, Ci = 6600pf
(Co = 500uF, Rs = 30mohm)
ON Semiconductor
Page 22
Waveform for varying gain bandwidth of controller
System optimized for gain bandwidth of MC33567 (5MHz).
Making gain bandwidth higher tends towards instability (gain peaking).
If designing with error amp compensation, can achieve stability by varying gain bandwidth.
Designed for (Af)o = 5MHz.
(MTD3055, Co=500uF, Rs=30mohm)
ON Semiconductor
Page 23
Transient Response in Stable LDO regulators Transient response for changes in output currents becomes straight forward if LDO
regulator closed loop response is stable.
Magnitude of transient depends on rate/magnitude of change and ESR of output capacitor.
Worse case is step change in output current ( ).OΔI
OΔV
OΔIOI
OV
Typical Transient Response Time for transient to return
to nominal output is proportional to closed loop response time.
Following is example of previous regulator design transient response for stable and “less than stable” conditions.
τt 5s
sOO RΔIΔV
ON Semiconductor
Page 24
sec1.5ts sec0.3τ (for optimized design)
(from graph)
Transient Response Example for Previous Design
From graph, optimized design is critically damped.
Over optimized designs slower but stable.
Designs outside of guidelines tend to oscillate.
Response time and transient amplitude agree with guidelines.
MTD3055: gm = 7, Ci = 2200pf
(Co = 500uF, Rs = 30mohm)
30mVΔVO
1AΔIO 30mRs
(from graph)
ON Semiconductor
Page 25
Specify design output voltage and current (steady state and transient).
Follow design guidelines.
Select controller best suited.
Simulate and prototype circuit.
Adjust components for optimal performance.
Presentation Summary
ON Semiconductor
Page 26
Reduces the total number of discrete & passive components thereby simplifying
and or reducing:
- System Cost - Procurement activity- Design Complexity - Overall size - Insertion cost - Component count - Performance inconsistencies - Solder reliability issues
A small-package-scale integration effort that combines multiple discrete, logic
and MOS devices, which may include passive devices (resistors, capacitors,
inductors).
MicroIntegrationTM
To TurnThis…
Into This…
ON Semiconductor
Page 27
Customer benefits
Improve marketplace opportunities
- Performance improvement
- Size reduction
- Reliability improvements
- Component interaction reduction
Reduce overhead costs
- Inventory Purchase Management
- Floor and shelf space
- Inspection
- Component Obsolescence
Lower manufacturing costs
- Assembly line setup time
- Capital equipment utilization
- Equipment costs
- Assembled wrong part ( yield)
- Reduced insertion costs
Lower materials costs
- Component costs
- Board/substrate costs
- Eliminate parts (eg.: shields)
ON Semiconductor
Page 28
Three types of products comprise the portfolio
+Vcc
I/O 1I/O 2
Transient Protection Arrays
Drive Circuits
Filter circuits
ON Semiconductor
Page 29
MicroIntegrationTM Markets
Automotive
– 42/14v systems, in-car entertainment systems
Computing
– Power Supplies, Laptop, PC/ MTB PC, Server/ MTB Server, Work Station, Main Frame, Mid-range,
Storage, Disk Drives, Peripherals, Printers, Monitors, Scanners
Consumer
– Power Supplies, Set-Top Boxes, Game Consoles, Smartcards, MP3s, DVDs, VCRs, Camcorders,
Digital Cameras, Appliances, CD/ DVD Players, Handheld Game Boys
Wireless & Portable
– Power Supplies/chargers, Mobile Phones, Cordless Phones, Pagers, HH PC/PDA,Smartcards,.
Transient Voltage Suppression (TVS)
ON Semiconductor
Page 31
Transient Protection Applications
IC Protection
IC CardI/OInput voltage
InputConnector
Filters
ON Semiconductor
Page 33
Low Pass Pi filter with TVS Protection
Frequency(MHz)
Attenuation
Defines Cut off frequency
Transient Protection diodes
10 100 1000 3,000
30
27
24
21
18
15
12
9
6
3
0
Gai
n(dB
)1
ON Semiconductor
Page 34
Filter Circuits
R
#1 #3
#6 #5 #4
1
2
3
NC
4
5
6
789101112
13
14
15
16
17
18
19 20 21 22 23 24
R
R
Drive Circuits
ON Semiconductor
Page 36
Drive Circuits
ON Semiconductor
Page 37
Analog DeviceMC33340, MC33342Battery Fast ChargeControllers
MicroIntegrationTM
Charge Controller Solution
ON Semiconductor
Page 38
Today’s Solution For Lithium-Ion Battery Management
ON Semiconductor
Page 39
Power Sequencer
Application:
3.3V/1.8V Power Sequence
Market Segment:
Computing
End Products:
Mother Board
ON Semiconductor
Page 40
Lithium Battery Driver
V
R22.2k
R110K
R1110k
Q22N7002LT1
V R67.5
R310k
V
R7230k
V5
4.0Vdc
R8470k
0
R1047k
D12D1N5231V
C222pf
R9
330
Q5
Q2SD1819
V60.3Vdc
D1MBR130P
V79Vdc
Q1Q2SD1819
Q4Q2SA1182
U1ALM324/MC
3
2
411
1
+
-
V+V-
OUT
Sim ulates 12 m a load for IC supply current.
S im ulates the battery.
Application:
Lithium Battery Driver
Market Segment:
Wireless,Consumer
IC control
Battery charge
End Products:
Hand Helds
ON Semiconductor
Page 41
Foldback Current Limiter
Q3Q2SC2712
D2D1N4148
Q1Q2SA1162
C11uf
D3D1N4148
R9 1k
R243k
R1210K
0
R114.3K
R101k
D4SMBJ10
12
R1 10
R3 10K
Q2Q2SA1162
9V
Output
Enable
Application:
Over Current Protection
Market Segment:
Consumer
End Products:
Set Top Box- 3 per box.
ON Semiconductor
Page 42
uP to FET Driver - Automotive
Application:
Bias Driver Circuit
Market Segment:
Automotive
R8
1k
Q5
Q2N2907
Q4
Q2N2222
R6
1k
Q1
Q2N2222
R7
1k
0
R5
1k
R10
1k
<Doc> <RevCode>
<Title>
A
1 1Friday, October 26, 2001
Title
Size Document Number Rev
Date: Sheet of
R3
1k
R9
1k
Q3
Q2N2222
R21k
R1
1k
R4
1k
uP input
3.3v
12 V Bat
FETinput
End Products:
Engine Control Module
ON Semiconductor
Page 43
MicroIntegrationTM Packages
MicroLeadless™
ON Semiconductor
Page 44
MicroLeadless™ Series
.040 x .020 .040 x .025
.080 x .080
0402 Diode Package 04025 Transistor Package
0808 Multilead Package
ON Semiconductor
Page 45
MicroLeadless™ Package Platform
80 mils80 mils
Can Package 4
RC filter/E
SD
circuits in 1
Device
ON Semiconductor
Page 46
Need library for parasitics
Bump inductance
Bump inductance
Need library for parasitics
Bonding inductance
Ground inductance
Flip chip model vs MicroLeadlessTM model
MicroLeadlessTM
Flip chip
ON Semiconductor
Page 47
Bumped flip chip S21 vs frequency
ON Semiconductor
Page 48
MicroLeadlessTM S21 vs frequency
ON Semiconductor
Page 49
Alex LaraApplications Engineer
• BSEE from University of Guadalajara
• 5 years experience in applications
• Motorola, ON Semiconductor
• Engineering Lab Manager
• Multiple articles and application notes
ON Semiconductor
Page 50
STANDARD DESCRIPTIVE JOB TITLE FOR AN APPLICATIONS ENGINEER WITHIN THE SEMICONDUCTOR MARKET: Develop new product ideas and specifications; build hardware/software prototypes to verify new product feasibility; design and build new product evaluation and demo boards; develop SPICE macro models and perform system simulations of new products and applications; assist in evaluating and debugging new products; evaluate and build comparative matrices of Competitive products; generate product briefs, data sheets and application notes; conduct on-site design programs of new products with market leading Alpha site companies; and interface with customers and sales staff and provide technical training to Sales and FAE's.
• Develop new applications concepts• New designs implementation• Technical Reports• Simulation of applications circuits• Design-ins• Applications Notes Development• Troubleshooting Customer Application needs• SPICE simulations Development
Applications Engineering Key ActivitiesApplications Engineering Key Activities
ON Semiconductor
Page 51
Universal Serial Bus
ON Semicondu
ctor
ON Semiconductor Applications Engineering Activities for USB Port Applications
ON Semiconductor
Page 52
Background
USB, or Universal Serial Bus, is a peripheral bus connectivity standard which was conceived, developed and is supported by a
group of leading companies in the computer and telecommunication industries – Compaq, DEC, IBM, Intel, Microsoft, NEC
and Northern Telecom. The current standard published and implemented on most of the USB devices is version 1.1,
nevertheless, the good news is, USB is getting even faster, USB 2.0 promises even higher data transfer rates, up to 480 Mbps.
The higher bandwidth of USB 2.0 will allow high performance peripherals, such as monitors, video conferencing cameras,
next-generation printers, and faster storage devices to be easily connected to the computer via USB. The higher data rate of
USB 2.0 will also open up the possibilities of new and exciting peripherals. USB 2.0 will be a significant step towards providing
additional I/O bandwidth and broadening the range of peripherals that may be attached to the PC.
USB 2.0 is expected to be both forward and backward compatible with USB 1.1. Existing USB peripherals will operate with no
change in a USB 2.0 system. Devices such as mice, keyboards and game pads, will not require the additional performance that
USB 2.0 offers and will operate as USB 1.1 devices. All USB devices are expected to co-exist in a USB 2.0 system. The higher
speed of USB 2.0 will greatly broaden the range of peripherals that may be attached to the PC. This increased performance will
also allow a greater number of USB devices to share the available bus bandwidth, up to the architectural limits of USB.
USB 1.1 devices operate at two different levels of speed:• Low speed, 1.8Mb/s equivalent to 900KHz (ENCODE, NRZI – Non Return Zero Inverter)• Full speed, 12Mb/s equivalent to 6MHz (ENCODE, NRZI – Non Return Zero Inverter)
USB 2.0 devices operate are compatible to operate at three different levels of speed:• Low speed, 1.8Mb/s equivalent to 900KHz (ENCODE, NRZI – Non Return Zero Inverter)• Full speed, 12Mb/s equivalent to 6MHz (ENCODE, NRZI – Non Return Zero Inverter)• High speed, 480Mb/s equivalent to 240MHz (ENCODE, NRZI – Non Return Zero Inverter)
ON Semiconductor
Page 53
USB allows for multiple peripheral connectivity with one (1) Host 1 PC.
Host PC-USB Hub Connection
D. Cameras
ScannersAdd other HUBs
Printers
PDAs
CellPhones
USB Connectivity
ON Semiconductor
Page 54
1) ESD Protection and surge protection• Devices must comply with the IEC 61000-4-2• Comply with Telcordia (formerly Bellcore) GR1089 on Surge 8x20usec waveform• USB 2.0 now requires Transmission Speeds up to 480Mbits/sec (240MHz), that forces to get lower capacitances (<5pF)
3) EMI Filtering / Termination – Detection • Pi Filters (RC), T Filters (LC)• Pull up & Pull down resistors for speed detection (Rpu, Rpd)• Impedance matching resistors (Zhsdrv)
2) Power Management• 5V – 3.3V Regulators• Features• Power switch (pending to research)
USB Device/Circuit/ComponentUSB Device/Circuit/ComponentProtectionProtection
USB Power Management USB Power Management forforHost and PeripheralsHost and Peripherals
USB Signal IntegrityUSB Signal Integrity
USB Opportunities Areas
ON Semiconductor
Page 55
Considerations for the USB ESD and TVS Protection
• IEC 61000-4-2 Contact and Air Discharge compliance for ESD Protection.• Obtaining the lowest insertion loss in the transmission line over a specific operating bandwidth.• Lower capacitances (less than 5pF5pF) to support USB 2.0USB 2.0 transmission speeds up to 480Mbits/sec (240MHz).480Mbits/sec (240MHz).
[example… ESD/TVS from connection your PDA to your computer]
USB ESD Applications
ON Semiconductor
Page 56
Typical USB ApplicationTypical USB ApplicationDual USB port protection
Single USB port protection
HOSTHOSTPCPC
D. D. CamerasCameras
PDAsPDAsPrintersPrintersScannersScanners
etc.etc.
USB ESD Applications (cont’d)
ON Semiconductor
Page 57
USB ESD Applications (cont’d)
Compliance with IEC 61000–4–2, ESD International Standard This International Standard relates to the immunity requirements and test methods for electrical and electronic equipment subjected to static electricity discharges, from operators directly, and to adjacent objects. It additionally defines ranges of test levels which relate to different environmental and installation conditions and establishes test procedures. The object of this standard is to establish a common and reproducible basis for evaluating the performance of electrical and electronic equipment when subjected to electrostatic discharges. In addition, it includes electrostatic discharges which may occur from personnel to objects near vital equipment.IEC 61000-4-2 Test Levels
This figure shows a real8KV contact waveform taken from the ESD generator.
This figure shows how the TVS clamps the ESD condition from 8KV to 8.7V, this is the way in which protection against ESD conditions is achieved by using TVS
ON Semiconductor
Page 58
USB ESD Applications (cont’d)
Low capacitance (less than 5pf) for High speed I/O Data lines (USB 2.0) “Low capacitance (< 5.0 pf)” is one of the most important characteristics that any device intended to be used in USB applications must have in order to minimize the signal attenuation at high speed data rate (480 Mbs, USB 2.0). This characteristic is critical, otherwise, the functionality of the USB system could be affected dramatically during high speed operation. Actually, the USB2.0 spec establishes that the capacitance between I/O data lines lines must no be higher than 5pf.
Junction capacitance ModelSimplified Junction capacitance Model
Theoretical principle used to predict the capacitance between I/O lines for the NUP4201DR2 device
C=4.52pf
Real Lab measurementsThe total devices characterized showedan average capacitance value of around 4.45 pf between I/O lines whichcomplies with the USB 2.0 specification (5.0 pf maximum) and reflects the resultsobtained from the pspice model.
ON Semiconductor
Page 59
USB EMI Filtering/TerminationEMI Filtering for USB 2.0 EMI Filtering for USB 2.0 Applications.Applications.
UpstreaUpstreamm
DownstreaDownstreamm
Common Common mode chokemode choke
inductorsinductors
For USB 2.0 applications, the usage of common mode choke inductors is very common for EMI filtering purposes since no extra capacitance is added between the I/O data lines.
ON Semiconductor
Page 60
USB EMI Filtering/TerminationEMI Filtering for USB 2.0 EMI Filtering for USB 2.0 Applications.Applications.
The equivalent PSPICE circuit for a TDK Choke model ACM2012-900-2P is shown below and also, its configurations for common and differential mode operation:
R1_3
14
C2_2
0.02p
R121G
TX1
C1_3
0.84p
Input1
0
C2
0.02p
R545
L1_4
3.1n
1 2
R1
14
R745
V4
TD =
TF = 500psPW = 1.58nsPER = 4.1666ns
V1 = 0
TR = 500ps
V2 = 300mVC12
0.95p
V
R3_2
0.065
Output1
R1_2
14
V
R3
0.065
R1_4
14
R3_4
0.065
L1
3.1n
1 2
R2_2
880
C12_20.95p
C1_2
0.84p
C1
0.84p
R6 45
R2
880
L1_3
3.1n
1 2
C1_4
0.84p
R4 45
R12_21G
R3_3
0.065
L1_2
3.1n
1 2
C1
0.84p
R2
880
R3
0.065
Input1
0
C1_2
0.84p
V4
TD =
TF = 500psPW = 1.58nsPER = 4.1666ns
V1 = 0
TR = 500ps
V2 = 300mV
L1_4
3.1n
1 2
R3_2
0.065C2_2
0.02p
R545
C12_20.95p
R1_2
14
TX1
R2_2
880
R1_3
14V
Output1
C1_4
0.84p
R3_4
0.065
C2
0.02p
L1_3
3.1n
1 2
R4 45
C1_3
0.84p
R1_4
14
V
R121G
L1_2
3.1n
1 2
L1
3.1n
1 2
R1
14
R12_21G
R745R6 45
C120.95p
R3_3
0.065
Common Mode
Differential Mode
ON Semiconductor
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USB EMI Filtering/TerminationEMI Filtering for USB 2.0 EMI Filtering for USB 2.0 Applications.Applications.Common and Differential mode response of the TDK Choke model ACM2012-900-
2P: Common Mode.In common mode operation, the Chokewill have very high attenuation and willnot allow the noise to go into the system. As shown in the graph (Common Mode), it starts havinghigh attenuation (-10dB or higher) when the frequency is around 50MHz.shows a high loss characteristics.
Fr e que nc y
1 . 0MHz 10MHz 100MHz 1. 0GHz 10GHz20*LOG10( V( R5: 2) / V( R4: 2) )
- 30
- 20
- 10
0
Fr e que nc y
1 . 0MHz 10MHz 100MHz 1. 0GHz 10GHz20* LOG10( V( R5: 2) / V( R4: 2) )
- 15
- 10
- 5
0
Differential Mode.In differential mode operation, the choke will not have high attenuation unless the noise signal is very high frequency (5GHz or higher). As shown in the graph, it starts having high attenuation (-10dB or higher) when the frequency is around 5GHz.
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USB EMI Filtering/TerminationEMI Filtering for USB 2.0 EMI Filtering for USB 2.0 Applications.Applications.
R6 45
R545
C1_4
0.84p
Output1
C12_20.95p
R745
L1_2
3.1n
1 2
R2_2
880
0
R1_2
14V-
L1_4
3.1n
1 2
R12_21G
C2
0.02p
C1
0.84p
V2
TD =
TF = 10psPW = 0.09nsPER = 0.2ns
V1 = 0
TR = 10ps
V2 = 100mV
Input1
V+
C120.95p
V1
TD =
TF = 500psPW = 1.583nsPER = 4.166ns
V1 = 0
TR = 500ps
V2 = 300mV
R4 45
V+
R1_3
14
R3_2
0.065
R121G
R3_3
0.065
R1
14
R3
0.065
R1_4
14
L1_3
3.1n
1 2
C1_3
0.84p
TX1
L1
3.1n
1 2
R2
880
V-C2_2
0.02p
C1_2
0.84p
R3_4
0.065
Ti me
0s 1ns 2ns 3ns 4ns 5ns 6ns 7ns 8ns 9ns 10nsV( R5: 2 , R7: 1) V( R4: 2 , R6: 2)
0V
50mV
100mV
150mV
200mV
TDK Choke Filtering response(Differential mode)
V1= USB 2.0 signal applied (240MHz)V2 = Noise signal (5GHz)
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USB EMI Filtering/TerminationEMI Filtering for USB 2.0 EMI Filtering for USB 2.0 Applications.Applications.
C13pf
V+
C33pf
R5 45
0
R2 7
V2
TD =
TF = 500psPW = 1.58nsPER = 4.166ns
V1 = 0
TR = 500ps
V2 = 300mV
R1 7
V+R645
V-
R445
V-
C23pf
L2 7nH1 2
L1 7nH1 2
R3 45
V1
TD =
TF = 10psPW = 90psPER = 200ps
V1 = 0
TR = 10ps
V2 = 100mV
C43pf
Ti me
0s 1ns 2ns 3ns 4ns 5ns 6ns 7ns 8ns 9ns 10nsV( R3: 1 , R5: 2) V( R6: 2 , R4: 1)
0V
50mV
100mV
150mV
200mV
V1= USB 2.0 signal applied (240MHz)V2 = Noise signal (5GHz)
LC Filter,Filtering response(Differential mode)
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CONCLUSION:
• Applications Engineers are key in the definition and understanding of the guide lines
for New Products Development.
• Applications Engineers are key to increase the business of the companies because
most of the time they represent an added value for the customers which allows to
create a relation-ship between the company and the designers, thereby, creation of
new business opportunities.
• Applications Engineers are key to promote the companies’ products by educating the
sales department, supporting trade-shows and developing demo-kits.
• Applications Engineers are key to win design-ins because they can help in
suggesting the most proper device for any particular application and also they can
show and explain the capability of the companies’ products.
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