OPA2192 Datasheet, PDF (31/51 Pages) Texas Instruments – OPAx192 36-V, Precision, Rail-to-Rail Input/Output, Low Offset Voltage,Low Input Bias Current Op Amp with e-trim

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9 Application and Implementation
OPA192, OPA2192, OPA4192
SBOS620D – DECEMBER 2013 – REVISED SEPTEMBER 2015
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.
9.1 Application Information
The OPAx192 family offers outstanding dc precision and ac performance. These devices operate up to 36-V
supply rails and offer true rail-to-rail input/output, ultralow offset voltage and offset voltage drift, as well as
10-MHz bandwidth and high capacitive load drive. These features make the OPAx192 a robust, high-
performance operational amplifier for high-voltage industrial applications.
9.2 Typical Applications
9.2.1 16-Bit Precision Multiplexed Data-Acquisition System
Figure 66 shows a 16-bit, differential, 4-channel, multiplexed data-acquisition system. This example is typical in
industrial applications that require low distortion and a high-voltage differential input. The circuit uses the
ADS8864, a 16-bit, 400-kSPS successive-approximation-resistor (SAR) analog-to-digital converter (ADC), along
with a precision, high-voltage, signal-conditioning front end, and a 4-channel differential multiplexer (mux). This
TI Precision Design details the process for optimizing the precision, high-voltage, front-end drive circuit using the
OPA192 and OPA140 to achieve excellent dynamic performance and linearity with the ADS8864.
1
Very Low Output Impedance
Input-Filter Bandwidth
2
High-Impedance Inputs
No Differential Input Clamps
Fast Settling-Time Requirements
3
Attenuate High-Voltage Input Signal
Fast-Settling Time Requirements
Stability of the Input Driver
4
Attenuate ADC Kickback Noise
VREF Output: Value and Accuracy
Low Temp and Long-Term Drift
±20-V,
10-kHz
Sine Wave
±20-V,
10-kHz
Sine Wave
OPA192
+
+
OPA192
CH0+
CH0-
4:2
Mux
OPA192
+
+
OPA192
CH3+
CH3-
n
High-Voltage Multiplexed Input
OPA192
+
+
OPA192
Gain
Network
Gain
Network
Gain
Network
OPA140
+
High-Voltage Level Translation
REF3240
Voltage
Divider
OPA350
VCM Generation Circuit
5
Fast logic transition
Voltage
Reference
RC Filter Buffer
Reference Driver
RC Filter
Antialiasing
Filter
VINP
REFP
SAR
ADC
VINM
CONV
16 Bits
400 kSPS
Counter
n
Shmidtt
Trigger
Delay
Digital Counter For Multiplexer
Figure 66. OPA192 in 16-Bit, 400-kSPS, 4-Channel, Multiplexed Data Acquisition System for High-Voltage
Inputs with Lowest Distortion
9.2.1.1 Design Requirements
The primary objective is to design a ±20 V, differential 4-channel multiplexed data acquisition system with lowest
distortion using the 16-bit ADS8864 at a throughput of 400 kSPS for a 10 kHz full-scale pure sine-wave input.
The design requirements for this block design are:
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