MB39A102 Datasheet, PDF (19/24 Pages) Fujitsu Component Limited. – Evaluation Board

MB39A102
• Diode current: Average value
The mean value of diode current must be within its rated current.
If the mean value of diode current is IF, it is obtained by the following formula.
IF
≥ IO ×
tOFF
t
≥ 0.25 × 0.583
≥ 0.146A
• Repeated peak reverse voltage
The repeated peak reverse voltage must be within its rated voltage.
If the repeated peak reverse voltage is VRRM, it is obtained by the following formula.
VRRM ≥ VIN (Max)
≥ 6V
(3) Inductor (SLF12565T-220M3R5 : TDK product)
22 µH (tolerance ± 20%) , rated current = 0.63 A
The condition for L to be a continuous current within the operating voltge range is obtained by the following
formula.
L
≥
VIN (Max) −VO
2IO
× tON
≥
6−2.5
2×0.25
×
1
500×10³
× 0.42
≥ 5.88 µH
The load current satisfying the continuous current condition is obtained by the following formula.
IO ≥
VO
2L
× tOFF
≥
2.5
2×22×10^−6
×
1
500×10³
×
(1−0.42)
≥ 66 mA
• Ripple current: Peak value
The peak ripple current must be within the rated current of the inductor.
If the peak ripple current is IL, it is obtained by the following formula.
IL ≥ IO +
VIN (Max) −VO
2L
× tON
≥ 0.25 +
6−2.5
2×22×10^−6
×
1
500×10³
× 0.417
≥ 0.316 A
• Ripple current: Peak-to-peak value
If the peak-to-peak ripple current is ∆IL, it is obtained by the following formula.
∆IL =
VIN (Max) −VO
L
× tON
=
6−2.5
22×10^−6
×
1
500×10³
× 0.42
=: 0.134 A
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