OPA192 Datasheet, PDF (25/35 Pages) Texas Instruments – High Voltage, Rail-to-Rail Input/Output, Precision Operational Amplifiers, e-trim Series

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OPA192
OPA2192
OPA4192
SBOS620A – DECEMBER 2013 – REVISED JANUARY 2014
16-BIT PRECISION MULTIPLEXED DATA-ACQUISITION SYSTEM
Figure 55 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 55. OPA192 in 16-Bit, 400-kSPS, 4-Channel, Multiplexed Data Acquisition System
for High-Voltage Inputs with Lowest Distortion
For step-by-step design procedure, circuit schematics, bill of materials, PCB files, simulation results, and test
results, refer to TI Precision Design TIDU181 - 16-bit, 400-kSPS, 4-Channel, Multiplexed Data Acquisition
System for High Voltage Inputs with Lowest Distortion
TINA-TI™ (Free Download Software)
TINA™ is a simple, powerful, and easy-to-use circuit simulation program based on a SPICE engine. TINA-TI is a
free, fully-functional version of the TINA software, preloaded with a library of macro models in addition to a range
of both passive and active models. TINA-TI provides all the conventional dc, transient, and frequency domain
analysis of SPICE, as well as additional design capabilities.
Available as a free download from the Analog eLab Design Center, TINA-TI offers extensive post-processing
capability that allows users to format results in a variety of ways. Virtual instruments offer the ability to select
input waveforms and probe circuit nodes, voltages, and waveforms, creating a dynamic quick-start tool.
NOTE
These files 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.
Copyright © 2013–2014, Texas Instruments Incorporated
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Product Folder Links: OPA192 OPA2192 OPA4192