OPA187_17 Datasheet, PDF (20/35 Pages) Texas Instruments – Drift, Low Power, Rail-to-Rail Output 36-V Operational Amplifiers Zero-Drift Series

OPA187, OPA2187, OPA4187
SBOS807 – DECEMBER 2016
8 Application and Implementation
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NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The OPAx187 operational amplifier combines precision offset and drift with excellent overall performance,
making it ideal for many precision applications. The precision offset drift of only 0.005 µV/°C provides stability
over the entire temperature range. In addition, the device pairs excellent CMRR, PSRR, and A_OL dc performance
with outstanding low-noise operation. As with all amplifiers, applications with noisy or high-impedance power
supplies require decoupling capacitors close to the device pins. In most cases, 0.1-µF capacitors are adequate.
The following application examples highlight only a few of the circuits where the OPAx187 can be used.
8.2 Typical Applications
8.2.1 High-Side Voltage-to-Current (V-I) Converter
The circuit shown in Figure 41 is a high-side voltage-to-current (V-I) converter. The converter translates an input
voltage of 0 V to 2 V into an output current of 0 mA to 100 mA. Figure 42 shows the measured transfer function
for this circuit. The low offset voltage and offset drift of the OPA2187 facilitate excellent dc accuracy for the
circuit.
V+
+
VIN
±
RS2
470
VRS2
IRS2
R4
10 k
C7
2200 pF
RS3
4.7
IRS3
VRS3
R5
330
+
Q2
R3
+
200
Q1
C6
1000 pF
R2
10
RS1
2k
VRS1
IRS1
RLOAD
VLOAD
ILOAD
Copyright © 2016, Texas Instruments Incorporated
Figure 41. High-Side Voltage-to-Current (V-I) Converter
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Copyright © 2016, Texas Instruments Incorporated
Product Folder Links: OPA187 OPA2187 OPA4187