XR76203-Q/XR76205-Q/XR76208-Q

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exar.com/XR76203-Q/XR76205-Q/XR76208-Q

Rev 1C

©2016-2017 Exar Corporation

Pin Assignments

Type: A = Analog, I = Input, O = Output, I/O = Input/Output, PWR = Power, OD = Open-Drain

Pin No.

Pin Name

Type

Description

1

ILIM

A

Over-current protection programming. Connect with a resistor to SW.

2

EN/MODE

I

Precision enable pin. Pulling this pin above 1.9V will turn the regulator on and it will operate in

CCM. If the voltage is raised above 3.0V then the regulator will operate in DCM/CCM depend-

ing on load

3

TON

A

Constant on-time programming pin. Connect with a resistor to AGND.

4

SS

A

Soft-Start pin. Connect an external capacitor between SS and AGND to program the soft-start

rate based on the 10uA internal source current.

5

PGOOD

O, OD

6

FB

A

Feedback input to feedback comparator. Connect with a set of resistors to VOUT and AGND

7, 10, AGND

Pad

AGND

A

Signal ground for control circuitry. Connect AGND Pad with a short trace to pins 7 and 10.

8

VIN

A

Supply input for the regulator’s LDO. Normally it is connected to PVIN.

9

VCC

A

The output of regulator’s LDO. For operation using a 5V rail, VCC should be shorted to VIN.

11-14, 20,

29, SW Pad

SW

PWR

Switch node. Drain of the low-side N-channel MOSFET. Source of the high-side MOSFET is

wire-bonded to the SW Pad. Pins 20 and 29 are internally connected to SW pad.

15-19,

PGND Pad

PGND

PWR

Ground of the power stage. Should be connected to the system’s power ground plane. Source

of the low-side MOSFET is wire-bonded to PGND Pad.

21-28, PVIN

Pad

PVIN

PWR

Input voltage for power stage. Drain of the high-side N-channel MOSFET.

30

BST

A

High-side driver supply pin. Connect a bootstrap capacitor between BST and pin 29.