10

10

Input Signal

124

1 nF

ADS1287

VIN

REF

CIN

1µF

COUT

10 µF

-

+

REF21xx

Copyright © 2017, Texas Instruments Incorporated

18

REF2125

SBAS798 – SEPTEMBER 2017

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Product Folder Links: REF2125

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Copyright © 2017, Texas Instruments Incorporated

9 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.

9.1 Application Information

As this device has many applications and setups, there are many situations that this datasheet can not

characterize in detail. Basic applications includes positive/negative voltage reference and data acquisition

systems. For more information see application sections in the REF32xx data sheet.

9.2 Typical Application: Basic Voltage Reference Connection

The circuit shown in Figure 28 shows the basic configuration for the REF2125 references. Connect bypass

capacitors according to the guidelines in Input and Output Capacitors.

Figure 28. Basic Reference Connection

9.2.1 Design Requirements

A detailed design procedure is described based on a design example. For this design example, use the

parameters listed in Table 1 as the input parameters.

Table 1. Design Example Parameters

DESIGN PARAMETER

VALUE

5 V

2.5 V

REF2125 input capacitor

1 µF

REF2125 output capacitor

10 µF

9.2.2 Detailed Design Procedure

9.2.2.1 Input and Output Capacitors

A 1-μF to 10-μF electrolytic or ceramic capacitor can be connected to the input to improve transient response in

applications where the supply voltage may fluctuate. Connect an additional 0.1-μF ceramic capacitor in parallel to

reduce high frequency supply noise.

A ceramic capacitor of at least 0.1 μF must be connected to the output to improve stability and help filter out high

frequency noise. An additional 1-μF to 10-μF electrolytic or ceramic capacitor can be added in parallel to improve

transient performance in response to sudden changes in load current; however, keep in mind that doing so

increases the turnon time of the device.