MB39A119 Datasheet, PDF (37/53 Pages) Fujitsu Component Limited. – DC/DC Converter IC of Synchronous Rectification for charging Li-ion battery

MB39A119
16.8 V output
VIN = 24 V (Max) , VO = 16.8 V, IO = 4.0 A, fosc = 500 kHz
1. N-ch MOS FET (µPA2752 : NEC product)
Main side
VDS = 30 V, VGS = ± 20 V, ID = 8 A, RDS (ON) = 25 mΩ (Typ) , Qg = 10 nC (Typ)
Synchronous rectification side
VDS = 30 V, VGS = ± 20 V, ID = 8 A, RDS (ON) = 25 mΩ (Typ) , Qg = 10 nC (Typ)
Drain current : Peak value
The peak drain current of this FET must be within its rated current.
If the FET’s peak drain current is ID, it is obtained by the following formula.
Main side
ID ≥ Io +
VIN−Vo
tON
2L
24−16.8
1
≥ 4.0 +
×
× 0.7
2 × 5.2 × 10^−6 500 × 10³
≥ 4.97 A
Synchronous rectification side
ID ≥ Io +
Vo
tOFF
2L
16.8
1
≥ 4.0 +
×
× (1 − 0.7)
2 × 5.2 × 10^−6 500 × 10³
≥ 4.97 A
2. Inductor (CDRH104R-5R2 : SUMIDA product)
5.2 µH (tolerance ± 30%) , rated current = 5.5 A
2 (VIN−Vo)
L≥
tON
Io
2 × (24−16.8)
1
≥
×
× 0.7
4.0
500 × 10³
≥ 5.04 µH
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