TI SLVU006A

Universal
Operational Amplifier
Evaluation Module
User’s Guide
March 1999
Mixed-Signal Products
SLVU006A
IMPORTANT NOTICE
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Copyright  1999, Texas Instruments Incorporated
Preface
Related Documentation From Texas Instruments
J
J
Amplifiers, Comparators, and Special Functions Data Book
(literature number SLYD011). This data book contains data sheets
and other information on the TI operational amplifiers that can be
used with this evaluation module.
Power Supply Circuits Data Book (literature number SLVD002).
This data book contains data sheets and other information on the TI
shunt regulators that can be used with this evaluation module.
FCC Warning
This equipment is intended for use in a laboratory test environment only. It
generates, uses, and can radiate radio frequency energy and has not been
tested for compliance with the limits of computing devices pursuant to subpart
J of part 15 of FCC rules, which are designed to provide reasonable protection
against radio frequency interference. Operation of this equipment in other
environments may cause interference with radio communications, in which
case the user at his own expense will be required to take whatever measures
may be required to correct this interference.
Trademarks
TI is a trademark of Texas Instruments Incorporated.
Chapter Title—Attribute Reference
iii
iv
Running Title—Attribute Reference
Contents
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1
Design Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
2
Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1
Physical Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2
Area 100 – SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3
Area 200 – TSSOP or MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4
Area 300 – SOT23-5A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5
Area 400 – SOT23-5B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.6
Component Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.7
Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
3
Example Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1
Schematic Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2
Sallen-Key Low-Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3
Sallen-Key High-Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4
Inverting Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5
Noninverting Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6
Two Operational Amplifier Instrumentation Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7
Differential Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1
3-1
3-2
3-3
3-5
3-6
3-7
3-9
Chapter Title—Attribute Reference
v
Running Title—Attribute Reference
Figures
2–1
2–2
2–3
2–4
2–5
2–6
2–7
2–8
2–9
Area 100 Schematic – SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Area 200 Schematic – TSSOP and MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLV22X1 Device Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Area 300 Schematic – SOT23–5A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLV2771 and TLV2461 Device Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Area 400 Schematic – SOT23–5B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Universal Operational Amplifier EVM Board Component Placement . . . . . . . . . . . . . . . . .
Universal Operational Amplifier EVM Board Layout Top . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Universal Operational Amplifier EVM Board Layout Bottom . . . . . . . . . . . . . . . . . . . . . . . . .
2-3
2-4
2-5
2-5
2-6
2-6
2-7
2-8
2-9
3–1
3–2
3–3
3–4
3–5
3–6
Sallen-Key Low-Pass Filter with Dual Supply Using Area 100 . . . . . . . . . . . . . . . . . . . . . . .
Sallen-Key High-Pass Filter with Single Supply Using Area 200 . . . . . . . . . . . . . . . . . . . . .
Inverting Amplifier with Dual Supply Using Area 300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Noninverting Amplifier with Single Supply Using Area 400 . . . . . . . . . . . . . . . . . . . . . . . . . .
Two Operational Amplifier Instrumentation Amplifier with Single Supply . . . . . . . . . . . . . .
Single Operational Amplifier Differential Amplifier with Single Supply . . . . . . . . . . . . . . . . .
3-2
3-4
3-5
3-6
3-8
3-9
vi
Chapter 1
Introduction
This User’s Guide describes a universal operational amplifier (op amp)
evaluation module (EVM) that simplifies evaluation of surface-mount op amp.
Topic
Page
1.1
Design Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–2
1.2
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–2
Introduction
1-1
Design Features
1.1 Design Features
The evaluation module board design allows many different circuits to be
constructed easily and quickly. The board has four separate circuit
development areas that can be snapped apart and separated. Areas 100 and
200 are for dual op amps in the SOIC and TSSOP/MSOP packages. Areas 300
and 400 are for SOT23–5 single operational amplifier packages. A few
possible circuits are listed below:
J
J
J
J
J
J
J
J
J
J
J
Voltage Follower
Noninverting Amplifier
Inverting Amplifier
Simple or Algebraic Summing Amplifier
Difference Amplifier
Current-to-Voltage Converter
Voltage–to-Current Converter
Integrator/Low-Pass Filter
Differentiator/High-Pass Filter
Instrumentation Amplifier
Sallen-Key Filter
The EVM PCB is of two-layer construction, with a ground plane on the solder
side. Circuit performance should be comparable to final production designs.
1.2 Power Requirements
The devices and designs that are used dictate the input power requirements.
Three input terminals are provided for each area of the board:
Vx+
GNDx
Vx–
Positive input power for area x00 i.e., V1+ ⇒ area 100
Ground reference for area x00
i.e., GND2 ⇒ area 200
Negative input power for area x00 i.e., V4– ⇒ area 400
Each area has four bypass capacitors, two for the positive supply, and two for
the negative supply. Each supply should have a 1-µF to 10-µF capacitor for low
frequency bypassing and a 0.01-µF to 0.1-µF capacitor for high frequency
bypassing.
When using single supply circuits, the negative supply is shorted to ground by
bridging Cx02 or Cx06, and power input is between Vx+ and GNDx. The
voltage reference circuitry is provided for single supply applications that
require a reference voltage to be generated.
1-2
Introduction
Chapter 2
Evaluation Module Layout
This chapter describes and shows the universal op amp EVM board layout and
the relationships between the four areas.
Topic
Page
2.1
Physical Consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
2.2
Area 100 – SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–3
2.3
Area 200 – TSSOP or MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–4
2.4
Area 300 – SOT23-5A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–5
2.5
Area 400 – SOT23-5B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–6
2.6
Component Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–7
2.7
Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–8
Evaluation Module Layout
2-1
Physical Considerations
2.1 Physical Considerations
The EVM board has four circuit development areas. If a specific area is
desired, it can be separated from the others by breaking along the score lines.
The circuit layout in each area supports an op amp package, voltage
reference, and ancillary devices. The op amp package is unique to each area
as described in the following paragraphs. The voltage reference and
supporting devices are the same for all areas. Surface-mount or through-hole
devices can be used for all capacitors and resistors on the board.
The voltage reference can be either surface mount or through hole. If surfacemount is desired, the TLV431ACDBV5 or TLV431AIDBV5 adjustable shunt
regulators can be used. If through hole is desired, then the TLV431ACLP,
TLV431AILP, TL431CLP, TL431ACLP, TL431ILP or TL431AILP adjustable
shunt regulators can be used. Refer to Texas Instruments’ Power Supply
Circuits Data Book (literature number SLVD002) for details on usage of these
shunt regulators.
Each passive component, resistor and capacitor, has a surface-mount 1206
foot print with through holes at 0.2″ spacing on the outside of the 1206 pads.
Therefore, either surface-mount or through-hole parts can be used.
2-2
Evaluation Module Layout
Area 100 – SOIC
2.2 Area 100 – SOIC
Area 100 uses 1xx reference designators, and is compatible with dual op amps
in 8-pin SOIC packages. Most dual op amps are available in this package. This
surface-mount package is designated by a D suffix in TI part numbers as in
TLV2422CD, TLV2342ID, TLV2252ID, etc. Refer to Figure 2–1 for a
schematic.
Figure 2–1. Area 100 Schematic – SOIC
C105
R118
V1+
R106
R105
C112
A101–
V1+
C104
V1+
R107
C103
A102–
GND1
R108
2
R119
A103+
C109
C110
3 +
1
4
R109
A104+
V1–
Power Supply Bypass
8
–
U101a
A1OUT
1/2 Dual OP Amp
V1–
V1–
R117
C111
C106
V1+
C102
R112
R114
VREF1
R103
R104
C107
B101–
R115
R
C
R102
U102
A
B102–
R101
6
R111
B103+
–
5 +
7
U101b
R110
R116
B1OUT
1/2 Dual OP Amp
B104+
Voltage Reference
R113
C108
C101
Evaluation Module Layout
2-3
Area 200 – TSSOP or MSOP
2.3 Area 200 – TSSOP or MSOP
Area 200 uses 2xx reference designators, and is compatible with dual op amps
in an 8-pin TSSOP or MSOP package. The TSSOP package is designated by
a PW suffix in TI part numbers as in TLV2422CPWLE, TLV2342IPWLE,
TLV2252AIPWLE, etc. The MSOP package is designated by a DGK suffix in
TI part numbers as in TLV2462CDGK. Refer to Figure 2–2 for a schematic.
Figure 2–2. Area 200 Schematic – TSSOP and MSOP
C205
R218
V2+
R206
R205
C212
A201–
V2+
C204
V2+
R207
C203
A202–
GND2
R208
2
R219
A203+
C209
C210
8
–
3 +
Power Supply Bypass
4
R209
A204+
V1–
1
U201a
A2OUT
1/2 Dual OP Amp
V2–
V2–
R217
C211
C206
V2+
C202
R212
R214
VREF2
R203
R204
C207
B201–
R215
R
C
R202
U202
A
B202–
R201
6
R211
B203+
5
–
7
+
U201b
R210
R216
B2OUT
1/2 Dual OP Amp
B204+
Voltage Reference
R213
C208
C201
2-4
Evaluation Module Layout
Area 300 – SOT23-5A
2.4 Area 300 – SOT23-5A
Area 300 uses 3xx reference designators, and is compatible with single op
amps in the 5-pin SOT-23 package with the pinout used for the TLV22X1 as
shown in Figure 2–3. This surface-mount package is designated by a DBV
suffix in TI part numbers as in TLV2211CDBV, TLV2221CDBV,
TLV2361CDBV, TLV2231IDBV, etc. Note: other parts like TLV2771CDBV,
TLV2711CDBV, TLV2461CDBV, etc., follow different pin-out schemes, which
are not compatible with this layout. See Figure 2–4 for a schematic.
Figure 2–3. TLV22X1 Device Pinout
IN+
1
VDD–/GND
2
IN–
3
5
VDD+
4
OUT
Figure 2–4. Area 300 Schematic – SOT23-5A
C305
R318
V3+
R306
R305
C312
301–
V3+
C304
V3+
R307
C303
302–
GND3
R308
3
R319
303+
C309
C310
R309
304+
V3–
Power Supply Bypass
5
–
1 +
4
2
3OUT
U301
V3–
V3–
R317
C311
C306
V3+
R314
VREF3
R315
R
C
U302
A
R316
Voltage Reference
Evaluation Module Layout
2-5
Area 400 – SOT23-5B
2.5 Area 400 – SOT23-5B
Area 400 uses 4xx reference designators, and is compatible with single op
amps in the 5-pin SOT-23 package with the pinout used for the TLV2271CDBV
and TLV2461CDBV as shown in Figure 2–5. This surface-mount package is
designated by a DBV suffix in TI part numbers as in TLV2771CDBV and
TLV2461CDBV. Note: earlier parts like TLV2221CDBV, TLV2231IDBV,
TLV2361CDB, and TLV2711CDBV, etc., follow a different pin-out scheme,
which is not compatible with this layout. Refer to Figure 2–6 for a schematic.
Figure 2–5. TLV2771 and TLV2461 Device Pinout
OUT
1
VDD–/GND
2
IN+
3
5
VDD+
4
IN–
Figure 2–6. Area 400 Schematic – SOT23-5B
C405
R418
V4+
R406
R405
C412
401–
V4+
C404
V4+
R407
C403
402–
GND4
R408
4
R419
403+
C409
C410
R409
404+
V4–
Power Supply Bypass
5
–
3 +
1
2
4OUT
U401
V4–
V4–
R417
C411
C406
V4+
R414
VREF4
R415
R
C
U402
A
R416
Voltage Reference
2-6
Evaluation Module Layout
Component Placement
2.6 Component Placement
Figure 2–7 shows component placement for the EVM board.
Figure 2–7. Universal Operational Amplifier EVM Board Component Placement
Area 100 – SOIC
Area 200 – TSSOP/MSOP
UNIVERSAL OP AMP EVM
SOIC SLOP120-1 1998
UNIVERSAL OP AMP EVM
TSSOP/MSOP SLOP120-2 1998
R101
R110
R219
R209
C101
R111
C212
R208
B104+
R102
C107
R218
C206
A204+
B103+
R103
R112
R217
R207
A203+
B102–
R104
R113
C211
R206
A202–
B101–
C102
C108
C210
R205
A201–
B1OUT
C103
R114
C209
C205
A2OUT
V1+
C104
U102
VREF1
GND1
R216
V2–
R215
VREF2
U201
GND2
U101
R115
V1–
U202
R116
A1OUT
V2+
C204
B2OUT
C105
C109
R214
C203
A101–
R105
C110
C208
C202
B201–
A102–
R106
C111
R213
R204
B202–
A103+
R107
R117
R212
R203
B203+
A104+
C106
R118
C207
R202
B204+
R108
C112
R211
C201
R109
R119
R210
R201
Score Line
R417
R415
R416
U402
R414
VREF4
404+
V4–
403+
4OUT
V4+
C411
R409
R408
R419
C406
C410
C409
U401
C404
C403
402–
GND4
401–
C405
R407
R405
R418
R316
UNIVERSAL OP AMP EVM
SOT23-5A SLOP120-3 1998
C412
R315
R406
R317
U302
R314
VREF3
304+
V3+
303+
GND3
V3–
3OUT
302–
301–
C311
R309
R308
R319
C303
C306
C304
C309
C310
C305
R305
R307
C312
R306
R318
U301
UNIVERSAL OP AMP EVM
SOT23-5B SLOP120-4 1998
Area 300 – SOT23-5A
Area 400 – SOT23-5B
Score Line
Evaluation Module Layout
2-7
Board Layout
2.7 Board Layout
Figures 2–8 and 2–9 show the EVM top and bottom board layouts,
respectively.
Figure 2–8. Universal Operational Amplifier EVM Board Layout Top
2-8
Evaluation Module Layout
Board Layout
Figure 2–9. Universal Operational Amplifier EVM Board Layout Bottom
Evaluation Module Layout
2-9
2-10
Evaluation Module Layout
Chapter 3
Example Circuits
This chapter shows and discusses several example circuits that can be
constructed using the universal operational amplifier EVM. The circuits are all
classic designs that can be found in most operational amplifier design books.
Topic
Page
3.1
Schematic Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–1
3.2
Sallen-Key Low-Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–2
3.3
Sallen-Key High-Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–3
3.4
Inverting Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–5
3.5
Noninverting Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–6
3.6
Two Operational Amplifier Instrumentation Amplifiers . . . . . . . . . . . 3–7
3.7
Differential Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–9
3.1 Schematic Conventions
Figures 3–1 through 3–6 show schematics for a sampling of circuits that can
be constructed on the Universal Operational Amplifier EVM. The components
that are placed on the board are shown in bold and unused components are
blanked out. Jumpers and other changes are noted. These examples are only
a few of the many circuits that can be built on the EVM.
Example Circuits
3-1
Sallen-Key Low-Pass Filter
3.2 Sallen-Key Low-Pass Filter
Figure 3–1 shows area 100 equipped with a dual operational amplifier
configured as a second-order Sallen-Key low-pass filter using dual-power
supplies.
Basic set up is done by proper choice of resistors R and mR, and capacitors
C and nC. The transfer function is:
V
OUT
V
IN
Where:
+
1
ǒ ń Ǔ ) ǒjńQǓǒfńfoǓ
1 – f fo
2
fo
+ 2p Ǹm1 n RC
Q
+ mǸm) n1
And
Figure 3–1. Sallen-Key Low-Pass Filter with Dual Supply Using Area 100
R118
C105
V1+
R105
R106
C104
0.1 µ F
C103
1µ F
R107
A102–
GND1
C109
0.1 µ F
A103+
C110
1µ F
R108
mR
2
R119
1
U101a
Vin
A1OUT
1/2 Dual OP Amp
V1–
+
R117
C111
–
1
1– (f/fo)2 + (j/Q)(f/fo)
=
8
4
R
A104+
V1–
–
3 +
R109
Power Supply Bypass
Vout
Vin
Jumper
V1+
A101–
V1+
V1–
C112
fo =
1
2π √mn RC
Q=
√mn
m+1
C106
nC
V1+
R112
C102
R101
R104
VREF1
R103
C107
Jumper
B101–
R114
R
C
R102
U102
A
B102–
B103+
R115
R101
6
–
5 +
R111
7
U101b
R110
B1OUT
1/2 Dual OP Amp
Voltage Reference
Not Used
Jumper
B104+
Not Used
R113
C108
C101
3-2
Example Circuits
Sallen-Key High-Pass Filter
3.3 Sallen-Key High-Pass Filter
Figure 3–2 shows area 200 equipped with a dual operational amplifier
configured as a second-order Sallen-Key high-pass filter using single-supply
power input.
Basic setup is done by proper choice of resistors R and mR, and capacitors
C and nC. Note that capacitors should be used for components R210 and
R211, and a resistor for C201. The transfer function for the circuit as shown
is:
V OUT
Where:
+ VIN
ȡȧ ǒ ń Ǔ
Ȣ ) ǒ ń Ǔǒ ń Ǔ
– f fo
1
fo
+ 2p Ǹm1 n RC
Q
+ nǸm) n1
And
2
ȣȧ)
ǒń Ǔ Ȥ
j Q f fo – f fo
2
VREF2
The TL431 adjustable precision shunt regulator, configured as shown,
provides a low impedance reference for the circuit at about 1/2 V2+ in a 5 V
system. Another option is to adjust resistors R215 and R216 for the desired
VREF2 voltage. The formula for calculating VREF2 is:
VREF2
ǒ
Ǔ
) R216
+ 2.50 V R215R216
Example Circuits
3-3
Sallen-Key High-Pass Filter
Figure 3–2. Sallen-Key High-Pass Filter with Single Supply Using Area 200
R218
C205
V2+
R205
R206
Jumper
C204
0.1 µF
C203
1 µF
R207
A202–
R208
R219
A203+
C209
C210
R209
A204+
V2–
V2–
Power Supply Bypass
C211
Jumper
V1–
Jumper
V2+
8
2
–
1
3 +
U201a
4
A201–
V2+
GND2
C212
A2OUT
1/2 Dual OP Amp
Not Used
R217
C206
R212
VREF2 = 2.5 V
V2+
R204
R203
C207
Jumper
B202–
6
R201
5
B204+
R215
R
mR
R210
C
A
C
+
R216
Vin
VOUT = VIN
–
7
+
U201b
1+(j/Q)(f/fo) – (f/fo)2
+ VREF2
B2OUT
1/2 Dual OP Amp
R211
B203+
U202
TL431ACLP
–(f/fo)2
Jumper
B201–
R202
R214
2.2 kΩ
C202
fo =
1
2π √mn RC
Q=
√mn
m+1
nC
C208
R213
–
Jumper B204 + to VREF2
Voltage Reference
3-4
C201
R
Example Circuits
Inverting Amplifier
3.4 Inverting Amplifier
Figure 3–3 shows area 300 equipped with a single operational amplifier
configured as an inverting amplifier using dual power supplies. Note the pinout
for the operational amplifier in area 300 follows the TLV2211 type pinout.
Basic setup is done by choice of input and feedback resistors. The transfer
function for the circuit as shown is:
V OUT
+ –VIN R305
R307
To cancel the effects of input bias current, set R317 = R305 || R307, or use a
0 Ω jumper for R317 if the operational amplifier is a low input bias operational
amplifier.
Figure 3–3. Inverting Amplifier with Dual Supply Using Area 300
C305
R318
V3+
R306
301–
V3+
C304
0.1 µF
C309
0.1 µF
R305
VOUT = –VIN
R307
V3+
C303
1 µF
R307
302–
GND3
V3–
R305
C312
R308
3
R319
303+
C310
1 µF
R309
+ 304+
–
1 +
5
4
2
V3–
Vin
Power Supply Bypass
V3–
V3+
–
C311
3OUT
U301
R317 = R305 II R307,
or Short if Using Low
Input Bias Op Amp
R317
C306
R314
VREF3
R315
R
C
U302
A
R316
Voltage Reference
Not Used
Example Circuits
3-5
Noninverting Amplifier
3.5 Noninverting Amplifier
Figure 3–4 shows area 400 equipped with a single operational amplifier
configured as a noninverting amplifier with single supply power input. Note the
pinout for the operational amplifier in area 400 follows the TLV2771 type
pinout.
Basic setup is done by choice of input and feedback resistors. The transfer
function for the circuit as shown is:
V
OUT
ǒ
Ǔ
) VREF4
+ VIN 1 ) R405
R407
Note that the input signal must be referenced to VREF4.
To cancel the effects of input bias current, set R409 = R405 || R407, or use a
0 Ω jumper for R409 if the operational amplifier is a low input bias operational
amplifier.
The TL431 adjustable precision shunt regulator, configured as shown,
provides a low impedance reference for the circuit at about 1/2 V4+ in a 3 V
system. Another option is to adjust resistors R415 and R416 for the desired
VREF4 voltage. The formula for calculating VREF4 is:
VREF4
ǒ
Ǔ
) R416
+ 1.24 V R415R416
Figure 3–4. Non-Inverting Amplifier with Single Supply Using Area 400
V4+
R418
C405
V4+
C404
0.1 µF
V4–
R406
C409
R405
C412
401–
C410
R407
5
402–
R408
403+
Power Supply Bypass V4–
(
V4+
Jumper 402 – to VREF4
Jumper
GND4
C403
1 µF
R419
R409
VOUT = VIN +1
4
–
3 +
4
2
R405
R407
) + VREF4
4OUT
U401
404+
V4–
V4+
+
R414
2.2 kΩ
C411
R417
Vin
–
Jumper
VREF4 = 1.24 V
C406
R415
C
R
U402 = TLV431ACDBV5
A
R416
Input Signal With
Reference to VREF4
R409 = R405 II R407,
or Short if Using Low Input
Bias Op Amp
Voltage Reference
3-6
Example Circuits
Two Operational Amplifier Instrumentation Amplifier
3.6 Two Operational Amplifier Instrumentation Amplifier
Figure 3–5 shows area 200 equipped with a dual operational amplifier
configured as a two-operational-amplifier instrumentation amplifier using a
voltage reference and single power supply.
Basic setup is done by choice of input and feedback resistors. The transfer
function for the circuit as shown is:
V
OUT
ǒ
Ǔ
+ VIN 1 ) 2R205
) R205
) VREF2
R207
R206
Where
R205 = R202
and
R206 = R204
To cancel the effects of input bias current, set R209 = R205 || R207 and set
R210 = R202 ||R204, or use a 0 Ω jumper for R209 and R210 if the operational
amplifier is a low input bias operational amplifier.
The TLV431 adjustable precision shunt regulator, configured as shown,
provides a low impedance reference for the circuit at about 1/2 V2+ in a 3 V
system. Another option is to adjust resistors R215 and R216 for the desired
VREF2 voltage. The formula for calculating VREF2 is:
VREF2
ǒ
Ǔ
) R216
+ 1.24 V R215R216
Example Circuits
3-7
Two Operational Amplifier Instrumentation Amplifier
Figure 3–5. Two Operational Amplifier Instrumentation Amplifier with Single Supply Using
Area 200
C205
R218
Jumper A201 – to B2OUT
R205
R206
R209 = R205– II R207
or Short if Using Low Input
Bias Op Amp
C212
Jumper
R207
A202–
V2+
R208
A204+
Jumper
V1–
–
3 +
R209
V2+
GND2
V2+
2
R219
A203+
C204
0.1 µF
C209
C211
Jumper
A202– to B201–
V2–
C206
Vin
C202
R212
Jumper VREF2 to B202–
R203
B201–
Jumper
B202–
C
R204
C207
Jumper
R202
R215
B203+
R201
6
R211
5
–
+
7
U201b
U202
A
TL431ACDBV5
R216
Voltage Reference
A2OUT
1/2 Dual OP Amp
R217
–
Jumper
4
V2–
+
R
1
U201a
R205 = R202
R206 = R204
C210
R214
2.2 kΩ
VREF2 = 1.24 V
)+ VREF2
8
C203
1 µF
Power Supply Bypass
V2+
(
2R205
R205
VOUT = Vin 1+ R207 + R206
A201–
B2OUT
1/2 Dual OP Amp
R210
B204+
R210 = R202 II R204
or Short if Using Low Input
Bias Op Amp
R213
C208
C201
3-8
Example Circuits
Differential Amplifier
3.7 Differential Amplifier
Figure 3–6 shows area 300 equipped with a single operational amplifier
configured as a differential amplifier using a voltage reference and single
power supply.
Basic setup is done by choice of input and feedback resistors. The transfer
function for the circuit as shown is:
V
OUT
Where
R305
R307
ǒ Ǔ)
+ VIN
R305
R307
VREF3
+ R309
R308
The TLV431 adjustable precision shunt regulator, configured as shown,
provides a low impedance reference for the circuit at about 1/2 V3+ in a 3 V
system. Another option is to adjust resistors R315 and R316 for the desired
VREF3 voltage. The formula for calculating VREF3 is:
VREF3
ǒ
Ǔ
) R316
+ 1.24 V R315R316
Figure 3–6. Single Operational Amplifier Differential Amplifier with Single Supply Using
Area 300
R318
C305
V3+
R305
R306
301–
V3+
C310
+
R307
302–
Vin
303+
–
R308
R309
3
R319
Jumper
304+
V3–
Power Supply Bypass
(
R305
Vout = Vin
R307
V3+
C303
1 µF
Jumper
C304
0.1 µF
GND3
C312
–
1 +
) + VREF3
5
4
2
3OUT
U301
V3–
R305
R309
=
R307
R308
V3–
C311
V3+
R317
R314
2.2 kΩ
C306
VREF3 = 1.24 V
R315
R
C
A
Jumper 304+ to VREF3
U302
TL431ACDBV5
R316
Voltage Reference
Example Circuits
3-9
3-10
Example Circuits