IR2085SPBF(2004) Ver la hoja de datos (PDF) - International Rectifier
Número de pieza
componentes Descripción
fabricante
IR2085SPBF
(Rev.:2004)
(Rev.:2004)
International Rectifier
IR2085SPBF Datasheet PDF : 9 Pages
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IR2085S&( PbF)
power MOSFETs are used on the secondary side in a
self-driven synchronous rectification topology.
DirectFETs practically eliminate MOSFET packaging
resistance, which maximizes circuit efficiency. The
DirectFET construction includes a copper “clip” across
the backside of the silicon, which enables top-sided
cooling and improved thermal performance. The
DirectFET gate drive voltage is clamped to an opti-
mum value of 7.5V with the IRF9956 dual SO-8
MOSFET. The secondary side bias scheme is de-
signed to allow outputs of two bus converters to be
connected in parallel, while operating from different
input voltages, and also to allow continuing output
current if one of the two input sources is shorted or
disconnected.
Two ferrite cores are used for the transformer and
inductor. The transformer core is a PQ20/16 (3F3) with
3:1 turns ratio and 1mil gap. The inductor core is an
E14/3.5/5 (3F3) with one turn and a 5mil gap. The
PCB has eight layers, with two layers for primary
windings that are connected in parallel and each has
three turns. Four layers are used for the secondary
windings. Each layer has one turn and two layers are
connected in parallel to get two sets of secondary
windings. 4 oz Cu PCB is recommended for the
primary and secondary windings. Each primary side
winding is placed between the two sets of the
secondary windings to balance the secondary side
current.
200
200
36~60Vinput
39k
3V
15V
IRF7380
7
7
Vdd
Vdd
1u
rm
36~60Vinput
IRF7493
3.3u
5566kk
IR2085S
cs Vb
1u
ct HO
474p7
G Vs
LO Vcc
Vdd
1
1u
1
3.3u
IRF7493
.1u
39k
9
9
9V
.1u 100k
22u 22u
3
IRF6603
10k
6~10Vout
3
IRF9956
3
IRF6603
10k
Figure 4 – IR2085S DC Bus converter reference design.
www.irf.com
7
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