User guide

Chip Information
TRANSISTOR COUNT: 1861
MAX668/MAX669
1.8V to 28V Input, PWM Step-Up
Controllers in µMAX
______________________________________________________________________________________ 17
MAX668
LDO
CS+
FB
SHDN
PGND
FREQREF
V
CC
GND
T1
2:1
EXT
V
IN
= +5V
T1: COILTRONICS CTX03-14232
+5V @ 400mA
+5V RETURN
0.1Ω
R2
301k
1%
510Ω
TLV431
610Ω0.068µF
R3
100k
1%
MBR0540L
MBR0540L
47µH
220µF
10V
0.22µF
1µF
100k
10k
MOC211
IRF7603
220µF
10V
0.1µF
Figure 7. Isolated +5V to +5V at 400mA Power Supply