OUT

GND

IN

C

C

REF31xx-Q1

To Input Power Supply

Via to Ground Plane

17

REF3112-Q1, REF3120-Q1, REF3125-Q1

REF3130-Q1, REF3133-Q1, REF3140-Q1

www.ti.com

SBVS299 – APRIL 2017

Product Folder Links: REF3112-Q1 REF3120-Q1 REF3125-Q1 REF3130-Q1 REF3133-Q1 REF3140-Q1

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Copyright © 2017, Texas Instruments Incorporated

10 Power Supply Recommendations

The REF31xx-Q1 family of references features an extremely low dropout voltage. With the exception of the

REF3112, which has a minimum supply requirement of 1.8 V, these references can be operated with a supply of

only 5 mV above the output voltage in an unloaded condition. For loaded conditions see Figure 4. TI

recommends a supply bypass capacitor greater than 0.47 μF.

11 Layout

11.1 Layout Guidelines

Figure 33 shows an example of a printed-circuit board (PCB) layout using the REF31xx-Q1. Some key

considerations are:

•

•

Decouple other active devices in the system per the device specifications.

•

Use a solid ground plane to help distribute heat and reduces electromagnetic interference (EMI) noise pickup.

•

Place the external components as close as possible to the device. This configuration prevents parasitic errors

(such as the Seebeck effect) from occurring.

•

Minimize trace length between the reference and bias connections to the INA and ADC to reduce noise

pickup.

•

Do not run sensitive analog traces in parallel with digital traces. Avoid crossing digital and analog traces if

possible, and only make perpendicular crossings when absolutely necessary.

11.2 Layout Example

Figure 33. Layout Example