International Rectifier IR3621 User Manual

IR3621 EVALUATION BOARD USER GUIDE
Dual output using MOSFETs in SO8 package
INTRODUCTION
DESCRIPTION
The IR3621 IC combines a Dual synchronous Buck con-
troller, providing a cost-effective, high performance and
flexible solution. The IR3621 can be configured in 2-in-
dependent output or as a 2-phase mode. The 2-phase
configuration is ideal for high current applications. The
IR3621 features 180 out of phase operation which re-
duces the required input/output capacitance. Other key
features offered by this device include two independent
programmable soft starts, PreBias start up, program-
mable switching frequency up to 500KHz per phase,
external frequency synchronization and under voltage
lockout for proper start up. The current limit is provided
by sensing the lower MOSFET's on-resistance for opti-
mum cost and performance.
INPUT/OUTPUT CONNECTIONS
The following is the input/output connections:
Inputs:
JP1: Vin and Gnd
JU4: VCC and Gnd
JU5: VCL
Outputs:
JP2: Vout1
JP5: Vout2
Scope Probe connections:
J1 and J3: Inductor point for L2 and L3
J2 and J4: Outputs for Vout1 and Vout2
PGOOD: JU1
SYNC: JU2
Rev.1.0
Dual_output_2xSO8
6/7/2005
SPECIFICATION DATA
This reference board is designed for Dual output
configuration and 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.
The connection points for dual output application are
shown in Figure 1. Connect the power supply cables
according to this figure, minimizing wire lengths to re-
duce losses in the wire. Test points J1, J2, J3 and J4
provide easy connection for oscilloscope voltage probe
to monitor the inductor points for each PWM section
and output voltages.
Application Data:
V = 12V
IN
V = 2.5V
OUT1
I = 10A
OUT1
V = 1.8V
OUT2
I = 10A
OUT2
∆V
= 50mV
OUT
F = 400KHz
S
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IRDC3621EVAL
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