Select R
1 to be approximately 1 kΩ, use a 1% resistor for best stability.
Component Values shown are for V
IN = 20V,
V
OUT = 10V, I
LOAD = 1A.
C
IN: — 470 μF, 35V, Aluminum Electrolytic Nichicon “PM Series”
C
OUT: — 220 μF, 35V Aluminum Electrolytic, Nichicon “PM Series”
D1 — 2A, 60V Schottky Rectifier, 21DQ06 (International Rectifier)
See
Inductor Selection Procedure L1 — 100 μH,
R
1 — 1 kΩ, 1%
R
2 — 7.15k, 1%
C
FF — 3.3 nF
Typical Values
C
SS—0.1 μF
C
DELAY—0.1 μF
R
PULL UP — 4.7k (use 22k if V
OUT is ≥ 45V)
† Small signal Schottky diode to prevent damage to feedback pin by negative spike when output is shorted. Required if V
IN > 40V