DATA SHEET
AAT2822/2823/2824/2825
TFT-LCD DC/DC Converter with WLED Driver and VCOM Buffer
Pin Descriptions
Pinout is preliminary and subject to change during development.
Pin Number
AAT2822 AAT2823 AAT28241
AAT28251
Symbol Function Description
Boost inductor node. Connect an inductor between IN and WLX.
WLX is high impedance in shutdown.
Power ground. Connect to GND underneath the IC.
1
2
1
2
n/a
2
n/a
2
WLX
O
PGND2
I/O
Internal reference bypass terminal. Connect a 0.1µF capaci-
tor from this terminal to analog ground (GND). External load
capability to 50µA.
3
3
3
3
REF
O
Negative charge-pump regulator feedback input. Regulates to
0V nominal.
Active high logic level enable for WLED Driver.
Negative charge-pump driver output. Output high level is VDD,
and low level is PGND.
4
5
6
4
5
6
4
n/a
6
4
n/a
6
FBN
WEN
DRVN
I
I
O
Positive and negative charge-pump driver supply voltage. By-
pass to PGND with a 0.1µF capacitor.
Positive charge-pump driver output. Output high level is VINP,
and low level is PGND.
Active high logic level enable input. Connect EN to IN for normal
operation.
7
8
9
7
8
9
7
8
9
7
8
9
VDD
DRVP
EN
PI
O
I
Positive charge-pump regulator feedback input. Regulates to
0.6V nominal. Connect feedback resistive divider to analog
ground (GND).
10
10
10
10
FBP
I
11
12
11
12
11
12
11
12
PGND1
LX
I/O
O
Power ground. Connect to GND underneath the IC.
Main boost regulator power MOSFET N-channel drain. Connect
output diode and output capacitor as close to PGND as possible.
Step-up regulator error-amplifier compensation point. Connect
a series RC from COMP to AGND.
Main boost regulator feedback input. Regulates to 0.6V nomi-
nal. Connect feedback resistive divider to analog ground (GND)
to set output voltage.
13
14
13
14
13
14
13
14
COMP
FB
I
O
Operational-amplifier power input. Power supply rail for the
operational amplifiers. Typically connected to VAVDD. Bypass
OPIN to GND with a 0.1µF capacitor.
15
n/a
15
n/a
OPIN
I
16
17
18
n/a
n/a
n/a
16
17
18
n/a
n/a
n/a
OP+
OP-
OUT
I
I
O
Operational-amplifier non-inverting input.
Operational-amplifier inverting input.
Operational-amplifier output.
White LED driver error-amplifier compensation point. Connect a
series RC from WCOMP to AGND.
Feedback pin. Connect a resistor to ground to set the maximum
LED current.
Feedback pin for over-voltage protection sense. Connect a re-
sistive divider between the boost converter output and ground.
Supply input. +2.5V to +5.5V input range. Bypass with a 0.1µF
capacitor between IN and GND, as close to the pins as possible.
Analog ground. Connect to power ground (PGND) underneath
the IC.
19
20
21
22
23
19
20
21
22
23
n/a
n/a
n/a
n/a
WCOMP
WFB
I
O
n/a
n/a
OVP
O
22
22
VIN
I
AGND
AGND
AGND
I/O
Dimming control input. Apply a PWM signal up to 1kHz to adjust
the WLED brightness from 100% to 5%, proportional to the
duty cycle of the PWM signal.
24
24
n/a
n/a
WDIM
I
15, 16,
17, 18
EP
1, 19, 20,
21
5, 24, EP
1, 15, 16, 17,
18, 19, 20, 21
5, 24, EP
n/a
EP
N/C
Not connected.
GND
Ground. EP = Exposed paddle, connect to PCB ground plane.
1. Future products. Please contact factory for availability.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
3
202081B
• Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 2, 2012
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
