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 = 2 A.
C
IN: — 470-μF, 35-V, Aluminum Electrolytic Nichicon
PM Series
C
OUT: — 220-μF, 35-V Aluminum Electrolytic, Nichicon
PM Series
D1 — 3.3-A, 60-V Schottky Rectifier, 31DQ06 (International Rectifier)
L1 — 47 μH, See
Application Curves
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
PULLUP — 4.7k (use 22k if V
OUT is ≥ 45 V)
† Small signal Schottky diode to prevent damage to feedback pin by negative spike when output is shorted. Required if V
IN > 40 V