REF7012QFKHT datasheet(32/43 Pages) TI

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10.3 Power Supply Recommendation

The REF70 family of references features a low-dropout voltage. These references can be operated with a supply

of only 50 mV above the output voltage for 0-mA output current conditions. The dropout voltage will vary with

the output current so refer to the dropout voltage to see typical dropout voltage requirements. TI recommends a

supply bypass capacitor ranging between 0.1 µF to 10 µF.

During start-up the REF70 can experience moments of high input current due to the output capacitors. The input

current can momentarily rise to ISC.

Temperature (°C)

-50

-25

100

125

100

150

200

250

300

0mA

5mA

10mA

Figure 10-6. Dropout Voltage vs Temperature

10.4 Layout

10.4.1 Layout Guidelines

Figure 10-7 and Figure 10-8 illustrate an example of a PCB layout for a data acquisition system using the

REF70. Some key considerations are:

• Connect low-ESR, 0.1-μF ceramic bypass capacitors at VIN of the REF70.

• Connect low-ESR, 1-uF to 100-uF capacitor at OUTF of the REF70.

• 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.

REF70

SNAS781G – OCTOBER 2020 – REVISED SEPTEMBER 2023

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REF7012QFKHT Datasheet(PDF) 32 Page - Texas Instruments