1Purdue University EET 368 Analog Integrated Circuits
Types of Op Amps
Op Amp Selection Criteria
Types
2Purdue University EET 368 Analog Integrated Circuits
Op Amp Selection CriteriaspeedDCsystem
Types
Types of Op Amps
3Purdue University EET 368 Analog Integrated Circuits
Op Amp Selection CriteriaspeedDCsystem
TypesgeneralFETCMOSwideband & current feedbackpower amps and buffers
Types of Op Amps
4Purdue University EET 368 Analog Integrated Circuits
Op amp Selection CriteriaHow must the circuit perform?
Speed
DC
System
5Purdue University EET 368 Analog Integrated Circuits
Op amp Selection CriteriaHow must the circuit perform?
Speedcircuit closed loop gain A CLgain accuracy (30%, 10%, 1%)f max (f H, f 10% , f 1% )Vout pk
DC
System
6Purdue University EET 368 Analog Integrated Circuits
Op amp Selection CriteriaHow must the circuit perform?
Speedcircuit closed loop gain A CL
gain accuracy (30%, 10%, 1%)f max (f H, f 10% , f 1% )Vout pk
DC
System
GBW
7Purdue University EET 368 Analog Integrated Circuits
Op amp Selection CriteriaHow must the circuit perform?
Speedcircuit closed loop gain A CL
gain accuracy (30%, 10%, 1%)f max (f H, f 10% , f 1% )Vout pk
DC
System
GBW
SR
8Purdue University EET 368 Analog Integrated Circuits
Op amp Selection CriteriaHow must the circuit perform?
Speed
DCsource impedanceDC output error allowabletemperature range
System
9Purdue University EET 368 Analog Integrated Circuits
Op amp Selection CriteriaHow must the circuit perform?
Speed
DC
Systempower available +/-V or just +, I available, battery?Vout & Iout neededVin $availability
10
Purdue University EET 368 Analog Integrated Circuits
General Purpose Op ampspeed 8MHzDC
cost examples
11
Purdue University EET 368 Analog Integrated Circuits
General Purpose Op ampspeed 8MHzDC
Ibias 100snAIos 10snAVios mVdrift 5microV/degC
cost examples
12
Purdue University EET 368 Analog Integrated Circuits
General Purpose Op ampspeed 8MHzDC
Ibias 100snAIos 10snAVios mVdrift 5microV/degC
cost lowest
13
Purdue University EET 368 Analog Integrated Circuits
General Purpose Op ampspeed 8MHzDC
Ibias 100snAIos 10snAVios mVdrift 5microV/degC
cost lowest
14
Purdue University EET 368 Analog Integrated Circuits
FET Input Op Ampsspeed 10MHzDC
cost examples
15
Purdue University EET 368 Analog Integrated Circuits
FET Input Op Ampsspeed 10MHzDC
much improved over general purposeIbias 100s pAIos 100s pAVios 0.1mVdrift 1microV/degC
cost examples
16
Purdue University EET 368 Analog Integrated Circuits
FET Input Op Ampsspeed 10MHzDC
much improved over general purposeIbias 100s pAIos 100s pAVios 0.1mVdrift 1microV/degC
cost few $sexamples
17
Purdue University EET 368 Analog Integrated Circuits
FET Input Op Ampsspeed 10MHzDC
much improved over general purposeIbias 100s pAIos 100s pAVios 0.1mVdrift 1microV/degC
cost few $sexamples
TLO84National Semiconductor's LF series
LT 1056
18
Purdue University EET 368 Analog Integrated Circuits
CMOS Op Amps
speed 1MHz or belowDC
cost
examples
system considerations
19
Purdue University EET 368 Analog Integrated Circuits
CMOS Op Amps
speed 1MHz or belowDC
much better than FETIbias & Ios fA (1E-15)Vios mVZin 1E12drift 10microV/degC
cost
examples
system considerations
20
Purdue University EET 368 Analog Integrated Circuits
CMOS Op Amps
speedDC
cost examples
system considerationsallows low supplies +1V +3Vprogrammable IQ 100 uAlow saturation voltage 10mVChopper Stabilized more later
21
Purdue University EET 368 Analog Integrated Circuits
CMOS Op Amps
speedDC
cost few $
examples
system considerations
22
Purdue University EET 368 Analog Integrated Circuits
CMOS Op Amps
speedDC
cost
examples
system considerations
LMCxxxx National SemiconductorCAxxxx RCAICLxxxx Intersil now GELTCxxxx Linear TechnologyTLCxxxx Texas Instruments
23
Purdue University EET 368 Analog Integrated Circuits
CMOS Op AmpsBeware!
Iout may be
24
Purdue University EET 368 Analog Integrated Circuits
Chopper Stabilized (CMOS) Op Amp
Speed MHzDC
System Considerations Examples
25
Purdue University EET 368 Analog Integrated Circuits
Chopper Stabilized (CMOS) Op Amp
SpeedDC
IB & Ios 10pAVios micro Volts
drift 0.01 to 0.5 microV/deg CSystem Considerations Examples
26
Purdue University EET 368 Analog Integrated Circuits
Chopper Stabilized (CMOS) Op Amp
SpeedDCSystem Considerations
same as other CMOS op amps
Examples
27
Purdue University EET 368 Analog Integrated Circuits
Chopper Stabilized (CMOS) Op Amp
Speed MHzDCSystem Considerations
same as other CMOS op amps
ExamplesLTC 1049, 1051, 1053, ... Linear TechnologyTLC2652P Texas InstrumentsAD 855x &AD857x Analog Devices
28
Purdue University EET 368 Analog Integrated Circuits
Chopper Stabilized Op Amp Schematic
nullpin
nullpin
In +
In -
Out
A
B
A' B'
V-
CXA CXB
nullamp
mainamp
29
Purdue University EET 368 Analog Integrated Circuits
Wide band Op Amps
SpeedGBW 600MHzfull power bandwidth 9MHzslew rate 600V/microsec
DC
Cost
30
Purdue University EET 368 Analog Integrated Circuits
Wide band Op Amps
SpeedGBW 600MHzfull power bandwidth 9MHzslew rate 600V/microsec
DC Ibias mA
Cost
31
Purdue University EET 368 Analog Integrated Circuits
Wide band Op Amps
SpeedGBW 10GHzfull power bandwidth 100MHzslew rate 600V/microsec
DC Ibias mA
Cost
$10 - $100
32
Purdue University EET 368 Analog Integrated Circuits
Current Feedback Op AmpsSpeed
fH is a constant, not affected by A CL
DC
System Considerations
33
Purdue University EET 368 Analog Integrated Circuits
Current Feedback Op AmpsSpeed
fH is a constant, not affected by A CL
DCIbias 100nA
Vios mV
Zin MOhms
System Considerations
34
Purdue University EET 368 Analog Integrated Circuits
Current Feedback Op AmpsSpeed
fH is a constant, not affected by ACL
DCIbias 100nA
Vios mV
Zin MOhms
System Considerations+5V to +18V
rf BEWARE!
Rf is usually specified
35
Purdue University EET 368 Analog Integrated Circuits
High Power Op Ampsaudio
drive a speaker 20-20kHz single +12V not an op amp
buffers
op amps
36
Purdue University EET 368 Analog Integrated Circuits
High Power Op Ampsaudio
drive a speaker 20-20kHz single +12V
not an op amp
buffers 100s mA
$
must be used inside a feedback loop
op amps
load
precision, inst rument qualityop amp
Rf
Ri
unity gainpower buffer
LT 1010
37
Purdue University EET 368 Analog Integrated Circuits
High Power Op Ampsaudio
drive a speaker 20-20kHz single +12V
not an op amp
buffers 100s mA
$
must be used inside a feedback loop
op amps
speed & DC similar to general purpose10 A & 100V
internal o r external I limitthermal shutdown$ to $10
Top Related