IRDC3899-P1V2
9/18/2012
1
USER GUIDE FOR IR3899 EVALUATION BOARD
1.2Vout
DESCRIPTION
The IR3899 is a synchronous buck
converter,
providing a
compact, high
performance and flexible solution in a small
4mm X 5 mm Power QFN package.
Key features offered by the IR3899 include
internal Digital Soft Start/Soft Stop, precision
0.5Vreference
voltage,
Power
Good
,
thermal protection, programmable switching
frequency, Enable input, input under-voltage
lockout for proper start-up, enhanced line/
load regulation with feed forward, external
frequency synchronization with smooth
clocking, internal LDO and pre-bias start-
up.
Output over-current protection function is
implemented by sensing the voltage developed
across the on-resistance of the synchronous
rectifier MOSFET for optimum cost and
performance and the current limit is thermally
compensated.
This user guide contains the schematic and bill
of materials for the IR3899 evaluation board.
The guide describes operation and use of the
evaluation board itself. Detailed application
information for IR3899 is available in the
IR3899 data sheet.
BOARD FEATURES
•
V
in
= +12V (+ 13.2V Max)
• V
out
= +1.2V @ 0- 9A
•
F
s
=400KHz
•
L= 1.0uH
•
C
in
= 4x10uF (ceramic 1206) + 1X330uF (electrolytic)
•
C
out
=6x47uF (ceramic 0805)
Sup
IR
Buck
TM