August 8, 2012 | ADVANCED DATASHEET | V2.1 | PD97603

5

IR3476

12A Highly Integrated SupIRBuck

TM

PIN DESCRIPTIONS

PIN #

PIN NAME

I/O LEVEL

PIN DESCRIPTION

1

FCCM

3.3V

Forced Continuous Conduction Mode (CCM). Ground this pin to enable diode

emulation mode or discontinuous conduction mode (DCM). Pull this pin to 3.3V

to operate in CCM under all load conditions.

2

ISET

Connecting resistor to PHASE pin sets over current trip point.

3

PGOOD

5V

Power good open drain output – pull up with a resistor to 3.3V

4, 17

GND

Reference

Bias return and signal reference.

5

FB

3.3V

Inverting input to PWM comparator, OVP / PGOOD sense.

6

SS

3.3V

Soft start/shutdown. This pin provides user programmable soft-start function.

Connect an external capacitor from this pin to GND to set the startup time of the

output voltage. The converter can be shutdown by pulling this pin below 0.3V.

7

NC

-

-

8

3VCBP

3.3V

For internal LDO. Bypass with a 1.0µF capacitor to GND.

9

NC

-

-

10

VCC

5V

VCC input. Gate drive supply. A minimum of 1.0µF ceramic capacitor is required.

11

PGND

Reference

Power return.

12

PHASE

VIN

Phase node (or switching node) of MOSFET half bridge.

13

VIN

VIN

Input voltage for the system.

14

BOOT

VIN + VCC

Bootstrapped gate drive supply – connect a capacitor to PHASE.

15

FF

VIN

Input voltage feed forward – sets on-time with a resistor to VIN.

16

EN

5V

Enable pin to turn on and off the device. Use two external resistors to set the

turn on threshold (see Electrical Specifications) for input voltage monitoring.