Test Circuit and Layout Guidelines
Fixed Output Voltage Versions
DS011394-11
C
IN
— 22 µF, 75V
Aluminum Electrolytic
C
OUT
— 220 µF, 25V
Aluminum Electrolytic
D1 — Schottky, 11DQ06
L1 — 330 µH, 52627
(for 5V in, 3.3V out, use
100 µH, RL-1284-100)
R1 — 2k, 0.1%
R2 — 6.12k, 0.1%
Adjustable Output Voltage Version
DS011394-12
FIGURE 2.
As in any switching regulator, layout is very important. Rap-
idly switching currents associated with wiring inductance
generate voltage transients which can cause problems. For
minimal inductance and ground loops, the length of the leads
indicated by
heavy lines should be kept as short as pos-
sible.
Single-point grounding (as indicated) or ground plane
construction should be used for best results. When using the
Adjustable version, physically locate the programming resis-
tors near the regulator, to keep the sensitive feedback wiring
short.
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