OPA189_17 Datasheet, PDF (24/36 Pages) Texas Instruments – Precision, 36-V, 14-MHz, MUX-Friendly Low-Noise, Rail-to-Rail Output, Zero-Drift Operational Amplifiers

OPA189, OPA2189, OPA4189
SBOS830 – JUNE 2017
9.2.3 Discrete INA + Attenuation for ADC With 3.3-V Supply
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NOTE
The TINA-TI files shown in the following sections require that either the TINA software
(from DesignSoft™) or TINA-TI software be installed. Download the free TINA-TI software
from the TINA-TI folder.
Figure 14 shows an example of how the OPAx189 is used as a high-voltage, high-impedance front-end for a
precision, discrete instrumentation amplifier with attenuation. The INA159 provides the attenuation that allows
this circuit to simply interface with 3.3-V or 5-V analog-to-digital converters (ADCs). Click the following link
download the TINA-TI file: Discrete INA.
15 V
VDIFF / 2
VCM ⁺
10V
±VDIFF / 2
OPAx189
RP
- 15 V _{10 NŸ}
RG
500 Ÿ
15 V
RN
10 NŸ
OPAx189
VOUTP
5V
Ref 1
Ref 2
INA159
Sense
VOUTN
VOUT(1)
15 V
Copyright © 2017, Texas Instruments Incorporated
(1) V_OUT = V_DIFF × (41 / 5) + (Ref 1) / 2.
Figure 14. Discrete INA + Attenuation for ADC With 3.3-V Supply
9.2.4 Bridge Amplifier
Figure 15 shows the basic configuration for a bridge amplifier. Click the following link to download the TINA-TI
file: Bridge Amplifier Circuit.
VEX
R1
R
R
+5V
R
R
VOUT
VREF
Copyright © 2017, Texas Instruments Incorporated
Figure 15. Bridge Amplifier
9.2.5 Low-Side Current Monitor
Figure 16 shows the OPAx189 configured in a low-side current-sensing application. The load current (I_LOAD)
creates a voltage drop across the shunt resistor (R_SHUNT). This voltage is amplified by the OPAx189, with a gain
of 201. The load current is set from 0 A to 500 mA, which corresponds to an output voltage range from 0 V to 10
V. The output range can be adjusted by changing the shunt resistor or gain of the configuration. Click the
following link to download the TINA-TI file: Current-Sensing Circuit.
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Product Folder Links: OPA189 OPA2189 OPA4189