11 Power Supply Recommendations

The REF34xx 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. TI recommends a supply bypass capacitor ranging

between 0.1 µF to 10 µF.

12 Layout

12.1 Layout Guidelines

Figure 12-1 illustrates an example of a PCB layout for a data acquisition system using the REF34xx. Some key

considerations are:

• Connect low-ESR, 0.1-μF ceramic bypass capacitors at IN, OUT_F, VOUT of the REF34xx and REF34xxT.

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

• Using a solid ground plane helps 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.

• 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.

12.2 Layout Example

1

6

2

3

4

GND_F

GND_S

EN

OUT_F

IN

REF34XX

C

5 OUT_S

Figure 12-1. REF34xx Layout Example

1

6

2

3

4

NC

GND

NC

VOUT

IN

REF34XXT

5

NC

C

C

Figure 12-2. REF34xxT Layout Example

REF3425, REF3430, REF3433, REF3440, REF3450

SBAS804F – SEPTEMBER 2017 – REVISED JUNE 2021

www.ti.com

22

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