SNVS106E – MAY 1999 – REVISED APRIL 2013
TEST CIRCUIT AND LAYOUT GUIDELINES
As in any switching regulator, layout is very important. Rapidly 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 possible. Single-point grounding (as
indicated) or ground plane construction should be used for best results. When using the Adjustable version,
physically locate the programming resistors near the regulator, to keep the sensitive feedback wiring short.
C
IN
— 100
μF,
75V, Aluminum Electrolytic
C
OUT
— 330
μF,
25V, Aluminum Electrolytic
D1 — Schottky, 11DQ06
L1 — 330
μH,
PE-52627 (for 5V in, 3.3V out, use 100
μH,
PE-92108)
Figure 25. Fixed Output Voltage Versions
where
V
REF
= 1.23V, R1 between 1k and 5k.
R1 — 2k, 0.1%
R2 — 6.12k, 0.1%
Pin numbers are for the TO-220 package.
Figure 26. Adjustable Output Voltage Version
12
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links:
TI [ TEXAS INSTRUMENTS ]
