Select R
1 to be approximately 1 kΩ, use a 1% resistor for best stability.
Component values shown are for V
IN = 20 V,
V
OUT = 10 V, I
LOAD = 1 A.
C
IN — 470-µF, 35-V aluminum electrolytic Nichicon
PM Series
C
OUT — 220-µF, 35-V aluminum electrolytic Nichicon
PM Series
D1 — 2-A, 60-V Schottky Rectifier, 21DQ06 (international rectifier)
L1 — 100 µH, see
Inductor Selection Procedure
R
1 — 1 kΩ, 1%
R
2 — 7.15 k, 1%
C
FF — 3.3 nF
Typical Values
C
SS — 0.1 µF
C
DELAY — 0.1 µF
R
PULL UP — 4.7 k (use 22 k if V
OUT is ≥ 45 V)
† Resistive divider is required to avoid exceeding maximum rating of 45 V, 3 mA on or into flag pin.
†† Small signal Schottky diode to prevent damage to feedback pin by negative spike when output is shorted. Required if V
IN > 40 V