OUT

GND

IN

C

C

REF29xx

To ADC

To Input Power Supply

Via to Ground Plane

18

REF2912, REF2920, REF2925

REF2930, REF2933, REF2940

SBVS033C – JUNE 2002 – REVISED JUNE 2016

www.ti.com

Product Folder Links: REF2912 REF2920 REF2925 REF2930 REF2933 REF2940

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Copyright © 2002–2016, Texas Instruments Incorporated

10 Power Supply Recommendations

The REF29xx family of references feature an extremely low-dropout voltage. These references can be operated

with a supply of only 50 mV above the output voltage. For loaded reference conditions, see Dropout Voltage vs

Load Current. Use a supply bypass capacitor greater than 0.47 µF.

11 Layout

11.1 Layout Guidelines

Figure 34 illustrates an example of a printed-circuit board (PCB) layout using the REF29xx. Some key

considerations are:

•

Connect low-ESR, 0.1-µF ceramic bypass capacitors at VIN of the REF29xx

•

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 to the device as possible. 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 34. REF29xx Layout Example