ADS8326

REF5040

OPA365

ESR

47µF

10µF

REFIN

CS

CLK

SDO

1nF

0-4V

124

Ÿ

REF5010, REF5020, REF5025, REF5030

REF5040, REF5045, REF5050

www.ti.com

SBOS410G – JUNE 2007 – REVISED NOVEMBER 2015

10 Applications and Implementation

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.

10.1 Application Information

Data acquisition systems often require stable voltage references to maintain accuracy. The REF50xx family

features low noise, very low drift, and high initial accuracy for high-performance data converters. Figure 42

shows the REF5040 in a basic data acquisition system.

10.2 Typical Applications

10.2.1 16-bit, 250-KSPS Data Acquisition System

Figure 42. Complete Data Acquisition System Using REF50xx

10.2.1.1 Design Requirements

When using REF50xx in the design, it is important to select proper output capacitor that does not create gain

peaking which increases total system noise. At the same time, the capacitor must be selected to provide required

filtering performance for the system. In addition, input bypass capacitor and noise reduction capacitors must be

added for optimum performances. During the design of the data acquisition system, equal consideration must be

given to the buffering analog input signal as well as the reference voltage. Having a properly designed input

buffer with an associated RC filter is a necessary requirement for good performance of the Data Acquisition

System.

10.2.1.2 Detailed Design Procedure

The OPA365 is used to drive the 16-bit Analog to Digital Converter (ADS8326). The RC filter at the output of the

OPA365 is used to reduce the charge kick-back created by the opening and closing of the sampling switch inside

the ADC. The RC filter should be designed such that the voltage at the sampling capacitor settles to 16-bit

accuracy within the acquisition time of the ADC. The bandwidth of the driving amplifier should at least be 4 times

the bandwidth of the RC filter.

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Product Folder Links: REF5010 REF5020 REF5025 REF5030 REF5040 REF5045 REF5050