International Rectifier IR3637 User Manual

IRDC3637EVAL

IR3637 EVALUATION BOARD USER GUIDE

DESCRIPTION

The IR3637 controller IC is designed to
provide a low cost synchronous Buck
regulator for on-board DC to DC
applications in a small 8-pin SOIC. The
output voltage can be precisely regulated
using the internal 0.8V reference voltage
for low voltage applications.
The IR3637 operates at a fixed internal
400KHz switching frequency to reduce the
component size.
The device features under-voltage lockout
for both input supplies, an external
programmable soft-start function as well as
output under-voltage detection that latches
off the device when an output short is
detected.

INPUT / OUTPUT CONNECTIONS

The following is the input / output connections:

Inputs:

JP1: Input (+5V) and GND
JU1: V

c

Outputs:

JP2: V

(+1.8V) and GND

out

Other Connections:

J1: Scope connection for V
J2: Scope connection for Inductor Point

out

The reference board is designed for

1.8V output using +5V and +12V
supplies. This will demonstrate the
main features of IC.

This user guide contains the schematic
and bill of materials, the design
guidelines are described in data sheet.

SPECIFICATION DATA

Vc= 12V
Vcc=Vin=5V
V

=1.8V

out

Iout =7A
Output Ripple = 50mV
Fs= 400KHz

The connection points are shown in
Figure1. Connect the power supply
cables according to this figure,
minimizing wire lengths to reduce
losses in the wire. Test points J1 and
J2 provide easy connection for
oscilloscope voltage probe to monitor
the inductor points and output voltage.

Rev1.0
4/29/2005

PACKAGE INFORMATION

1

Fb

2

Vcc

3

LDrv

4

Gnd HDrv

8
7
6
5

SS/SD
Comp
Vc

1

CONNECTION DIAGRAM

IRDC3637EVAL

+12V
Supply

+5V
Supply

Figure 1 – Connection diagram of evaluation board for IR3637

7A
Load

Rev1.0
4/29/2005

2

LAYOUT

The top side (component) layer for
IR3637 Eval board is shown in Figure

2. The input capacitors are all located
close to the MOSFETs. All the
decoupling capacitors, and feedback
components are located close to IC.
The feedback resistors are tied to the
output voltage at the point of
regulation.

IRDC3637EVAL

The PCB is 4-layers board, one
layer is dedicated to Power GND
and the analog GND is kept
separated from the PGND and it is
connected at a single point.

Figure 2 – Top layer of evaluation board for IR3637

Rev1.0
4/29/2005

3