September 10, 2012 | FINAL DATASHEET

4

IR3558

45A Integrated PowIRstage®

PIN DESCRIPTIONS

PIN #

PIN NAME

PIN DESCRIPTION

1

VCC

Bias voltage for control logic. Connect VCC to a 5V supply. Connect a minimum 0.1uF

capacitor between VCC and LGND.

2

LVCC

Supply voltage for the low-side driver. Connect LVCC to a 4.5V to 13.2V supply. Connect

a minimum 0.1uF capacitor between LVCC and PGND (pin 4).

3

HVCC

Supply voltage for the high-side driver. Connect HVCC to a 4.5V to 13.2V supply.

Connect a minimum 0.1uF capacitor between HVCC and PGND (pin 4).

4, 14, 15, 27

PGND

Power ground of low-side MOSFET driver and the synchronous MOSFET.

5, 28

GATEL

Low-side MOSFET driver pins that can be connected to a test point in order to observe

the waveform.

6 – 13

SW

Switch node of synchronous buck converter.

16 – 19

VIN

High current input voltage connection. Recommended operating range is 4.5V to 15V.

Connect at least two 10uF 1206 ceramic capacitors and a 0.1uF 0402 ceramic capacitor.

Place the capacitors as close as possible to VIN pins and PGND pins (14-15). The 0.1uF

0402 capacitor should be on the same side of the PCB as the IR3558.

20

BOOST

Bootstrap capacitor connection. The bootstrap capacitor provides the charge to turn on

the control MOSFET. Connect a minimum 0.22µF capacitor from BOOST to SW pin. Place

the capacitor as close to BOOST pin as possible and minimize the parasitic inductance of

the connection from the capacitor to SW pin. A 1Ω to 4Ω series resistor may be added

to slow down the SW rising and limit the surge current into the bootstrap capacitor on

start-up.

21

OT#

Open drain output of the phase fault circuits. Connect to an external pull-up resistor.

Output is low when an over temperature condition inside the device is detected.

22

PWM

PWM control input. Connect this pin to the PWM output of a controller that outputs

either a 3.3V tri-state PWM signal or a 1.8V International Rectifier’s Active Tri-Level

PWM signal.

23

EN

Enable control. 3.3V logic level input. Pulling this pin high to enable the device and

grounding it to shut down both MOSFETs and enter low quiescent mode.

24

LGND

Signal ground. Driver control logic, analog circuits and IC substrate are referenced to

this pin.

25

MODE

PWM mode selection. Grounding this pin to select the regular 3.3V tri-state PWM logic

or connecting it to VCC to select International Rectifier’s Active Tri-Level PWM logic.

26

OTSET

Over temperature set. The default is 150°C when this pin is floated. A resistor from this

pin to ground programs the over temperature threshold from 70°C to 150°C. See “Over