Four-Channel Backlight Driver with Dual LDOs
Pin Descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
EP
AAT2845
Symbol
D2
D1
LDOB
IN
PGND
IN
FBA
LDOA
C2-
C2+
OUT
C1-
C1+
EN/SET
ENLDO
D4
D3
GND
CBP
FBB
Function
Current sink input #2.
Current sink input #1.
Output of LDO B. Connect a 2.2µF or larger ceramic capacitor to ground.
Input power supply for charge pump. Requires a 1µF or larger ceramic capacitor connected
between this pin and ground.
Power ground.
Input power pin for both LDOs. Connect a 1µF or larger ceramic capacitor from this pin to
PGND.
Feedback pin of LDO A. Regulated at 1.2V.
Output of LDO A. Connect a 2.2µF or larger ceramic capacitor to ground.
Flying capacitor 2 negative terminal.
Flying capacitor 2 positive terminal. Connect a 1µF ceramic capacitor between C2+ and C2-.
Charge pump output to drive load circuit. Connect a 1µF or larger ceramic capacitor between
this pin and PGND.
Flying capacitor 1 negative terminal.
Flying capacitor 1 positive terminal. Connect a 1µF ceramic capacitor between C1+ and C1-.
S
2
Cwire control pin for backlighting.
Enable pin for LDO A and B.
Current sink input #4.
Current sink input #3.
Ground.
Bypass pin for the internal reference.
Feedback pin of LDO B. Regulated at 1.2V. Connect a 0.1µF ceramic capacitor from this pin
to GND.
Exposed paddle (bottom); connect to PGND as closely as possible to the device.
Pin Configuration
TQFN34-20
(Top View)
D3
GND
CBP
FBB
20
19
18
17
D2
D1
LDOB
IN
PGND
IN
1
2
3
4
5
6
10
9
7
8
16
15
14
13
12
11
D4
ENLDO
EN/SET
C1+
C1-
OUT
C2+
C2-
LDOA
FBA
2
2845.2006.12.1.0
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
