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XR77129

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exar.com/XR77129

Rev 1A

Pin Configuration

Pin Assignments

Pin No.

Pin Name

Description

1

LDOOUT

Output of the standby LDO. This is a micro power LDO that needs to be configured or com-

manded to turn on.

2

AGND

Analog ground pin. This is the small signal ground connection.

3

CPLL

Connect to a 2.2nF capacitor to GND.

4

AVDD

Output of the internal 1.8V LDO. A decoupling capacitor should be placed between AVDD and

AGND close to the chip.

5, 6, 7, 8

VOUT1, VOUT2, VOUT3, VOUT4

Connect to the output of the corresponding power stage.The output is sampled at least once

every switching cycle.

9,10

GPIO0, GPIO1

These pins can be configured as inputs or outputs to implement custom flags, power good sig-

nals, enable/disable controls and synchronization to an external clock.

11, 12

SDA, SCL