Rainbow Electronics MAX686 - Manual (Page 8)

MAX686
DAC-Controlled Boost/Inverter
LCD Bias Supply with Internal Switch
8 _______________________________________________________________________________________
MAX686
V
CC
V DD
V OUT
C F
22pF
V IN = 0.8V TO 27.5V
UP
SHDN
DN
POL
GND PGND
LX
L1
22 µ H
DACOUT
LCDON
FB
REF
POK
ISET
0.1 µ F
R3
R2
D1
MBR0530L
R1
ON/OFF
DAC CONTROL
15 µ F
4.7 µ F
V CC = 2.7V TO 5.5V
0.1 µ F
0.1 µ F
Figure 1. Boost Configuration: Positive Output Voltage
MAX686
V CC
V
DD
V IN
≤ | V OUT
| ≤ 27.5V
MBRO530L
D2
MBRO530L
NEGATIVE
OUTPUT
VOLTAGE
V IN = 0.8V TO 27.5V
UP
POL
SHDN
DN
GND PGND
LX
DACOUT
LCDON
FB
REF
POK
ISET
0.1 µ F
2.2 µ F
L1
22 µ H
D1
R4
2 Ω
2.2 µ F
R3
R2 R1
ON/OFF
DAC CONTROL
C F
100pF
V CC = 2.7V TO 5.5V
0.1 µ F
15 µ F
Figure 2. Negative Output Voltage Application Circuit