ADS7040 Datasheet, PDF (21/38 Pages) Texas Instruments – Ultra-Low Power, Ultra-Small Size, 8-Bit, 1-MSPS, SAR ADC

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9 Application and Implementation
ADS7040
SBAS676A – NOVEMBER 2014 – REVISED NOVEMBER 2014
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 two primary circuits required to maximize the performance of a high-precision, successive approximation
register (SAR), analog-to-digital converter (ADC) are the input driver and the reference driver circuits. This
section details some general principles for designing the input driver circuit, reference driver circuit, and provides
some application circuits designed for the ADS7040.
9.2 Typical Applications
9.2.1 Single-Supply DAQ with the ADS7040
AVDD
AVDD
V_IN+
+
±
OPA314
+
Input Driver
200 
1.5 nF
AINP
AVDD
Device
AINM
GND
Device: 8-Bit, 1-MSPS,
Single-Ended Input
Figure 39. DAQ Circuit: Single-Supply DAQ
9.2.1.1 Design Requirements
The goal of this application is to design a single-supply digital acquisition (DAQ) circuit based on the ADS7040
with SNR greater than 49 dB and THD less than –70 dB for input frequencies of 5 kHz at a throughput of
1 MSPS.
9.2.1.2 Detailed Design Procedure
The input driver circuit for a high-precision ADC mainly consists of two parts: a driving amplifier and an
antialiasing filter. Careful design of the front-end circuit is critical to meet the linearity and noise performance of a
high-precision ADC.
Copyright © 2014, Texas Instruments Incorporated
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