MAX1620 Datasheet, PDF (19/20 Pages) Maxim Integrated Products – Digitally Adjustable LCD Bias Supplies

Digitally Adjustable LCD Bias Supplies
2V
TO
12V
R1
R8
C3
360k
10k
10µF
D3 1N6263 (ANY SCHOTTKY)
R2
TO REF
100k
3
5 ^BATT
U1
14
LX ₁₆
RS
470Ω
11 ^POK
DHI ₁₅
3V
TO
5.5V
C1
0.1µF
7 ^VDD
4 ^POL
MAX1620
MAX1621
1 ^{SHDN (SUS)}
DLO ₁₃
PGND
10
R3
300k
DN (SDA)
2 _{UP (SCL)}
6 _REF
DOUT ₉
FB
C2
12 _AGND
8
LCDON
0.1µF
( ) ARE FOR MAX1621.
NOTE: CONNECTIONS TO DIGITAL INPUTS NOT SHOWN.
L1
220µH
D1
MBRS0540+
C5
10µF
Q1
MMBT4401LT1
R5
2.2M
R4
C6
300k
100pF
12.5V
TO
R6
23.5V OUT
150k
Q1
MMBT2907
R7
150k
VOUTSW
OPTIONAL
Figure 10. Positive Output with Bipolar Switching Transistor
___________________________________________________Simplified Block Diagram
V_DD
AGND
DN (SDA)
UP (SCL)
SHDN (SUS)
POL
REF
FB
BATT
BIAS
SHDN
DIGITAL
INTERFACE
1.5V
1.0V
5-BIT
DAC
BANDGAP
REFERENCE
ON-TIME
CONTROL
MAX1620
MAX1621
DOUT
LX
DHI
DLO
PGND
LCDON
POK
( ) ARE FOR MAX1621 ONLY.
___________________Chip Information
TRANSISTOR COUNT: 341
SUBSTRATE CONNECTED TO AGND
______________________________________________________________________________________ 19