HM83 View Datasheet(PDF) - Unspecified
Part Name
Description
Manufacturer
HM83 Datasheet PDF : 8 Pages
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H0
Table1: Suggested Inductors
Component
Supplier
Series
Inductance
(uH)
TAIYO YUDEN NR 3015
2.2
TAIYO YUDEN NR 3015
4.7
Sumida
CDRH2D14
2.2
Sumida
CDRH2D14
4.7
GOTREND
GTSD32
2.2
GOTREND
GTSD32
4.7
DCR
(mΩ)
60
120
75
135
58
146
Current Rating
(mA)
1480
1020
1500
1000
1500
1100
Dimensions
(mm)
3 x 3 x 1.5
3 x 3 x 1.5
4.5 x 3.2 x 1.55
4.5 x 3.2 x 1.55
3.85 x 3.85 x 1.8
3.85 x 3.85 x 1.8
Output and Input Capacitor Selection
In continuous mode, the source current of the top MOSFET is a square wave of duty cycle VOUT/VIN. To
prevent large voltage transients, a low ESR input capacitor sized for the maximum RMS current must be
used. The maximum RMS capacitor current is given by:
This formula has a maximum at VIN = 2VOUT, where IRMS = IOUT/2. This simple worst-case condition is
commonly used for design because even significant deviations do not offer much relief. Note that the
capacitor manufacturer’s ripple current ratings are often based on 2000 hours of life. This makes it
advisable to further derate the capacitor, or choose a capacitor rated at a higher temperature than
required. Always consult the manufacturer if there is any question.
The selection of COUT is driven by the required effective series resistance (ESR). Typically, once the
ESR requirement for COUT has been met, the RMS current rating generally far exceeds the IRIPPLE(P-P)
requirement. The output ripple ∆VOUT is determined by:
Where f = operating frequency, COUT = output capacitance and ∆IL = ripple current in the inductor. For a
fixed output voltage, the output ripple is highest at maximum input voltage since ∆IL increases with input
voltage.
Aluminum electrolytic and dry tantalum capacitors are both available in surface mount configurations. In
the case of tantalum, it is critical that the capacitors are surge tested for use in switching power supplies.
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