PRODUCT DATASHEET
AAT2861
ChargePump
TM
Backlight/Flash LED Driver and Multiple LDO Lighting Management Unit
Pin Descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Symbol
OUT
C2+
EN/SET
FL_EN
EN_LDOA
EN_LDOB/C
AGND
LDOC
IN
LDOB
LDOA
BL1
BL2
BL3
BL4
BL5
BL6
Description
Charge pump output. OUT is the output of the charge pump and supplies current to the backlight and
fl
ash
LEDs. Connect the backlight and
fl
ash LED anodes to OUT. Bypass OUT to PGND with a 2.2μF or larger
ceramic capacitor as close to the AAT2861 as possible.
Positive terminal of charge pump capacitor 2. Connect the 1μF charge pump capacitor 2 from C2+ to C2-.
AS
2
Cwire serial input. EN/SET is the address and data input of the AS
2
Cwire serial interface. AS
2
Cwire is
used to control backlight,
fl
ash and LDO functions.
Flash enable. FL_EN is the enable control for the Flash LEDs. For the FL_EN pin to enable the
fl
ash current,
the EN/SET pin must also be pulled high.
LDO A enable pin. EN_LDOA turns on or off LDO regulator A. The EN/SET pin must also be pulled high for
LDO A to be enabled. The EN_LDOA input can be overwritten via the AS
2
Cwire interface to disable LDO A.
LDO B and LDO C enable pin. EN_LDOB/C enables both LDO regulators B and C. The EN/SET pin must
also be pulled high for the LDO regulators to be enabled. The EN_LDOB/C input can be overwritten via the
AS
2
Cwire interface to disable either LDO B or LDO C.
Analog ground. Connect AGND to PGND at a single point as close to the AAT2861 as possible.
LDOC is the voltage output of LDO C. Bypass LDOC to AGND with a 2.2μF or larger capacitor as close to
the AAT2861 as possible.
Input power pin for all three LDOs. Connect Pin 9 to Pin 23 with as short a PCB trace as practical.
LDOB is the voltage output of LDO B. Bypass LDOB to AGND with a 2.2μF or greater capacitor as close to
the AAT2861 as possible.
LDOA is the voltage output of LDO A. Bypass LDOA to AGND with a 2.2μF or larger ceramic capacitor as
close to the AAT2861 as possible.
Backlight LED 1 current sink. BL1 controls the current through backlight LED 1. Connect the cathode of
backlight LED 1 to BL1. If not used, connect BL1 to OUT.
Backlight LED 2 current sink. BL2 controls the current through backlight LED 2. Connect the cathode of
backlight LED 2 to BL2. If not used, connect BL2 to OUT.
Backlight LED 3 current sink. BL3 controls the current through backlight LED 3. Connect the cathode of
backlight LED 3 to BL3. If not used, connect BL3 to OUT.
Backlight LED 4 current sink. BL4 controls the current through backlight LED 4. Connect the cathode of
backlight LED 4 to BL4. If not used, connect BL4 to OUT.
Backlight LED 5 current sink. BL5 controls the current through backlight LED 5. Connect the cathode of
backlight LED 5 to BL5. If not used, connect BL5 to OUT.
Backlight LED 6 current sink. BL6 controls the current through backlight LED 6. Connect the cathode of
backlight LED 6 to BL6. If not used, connect BL6 to OUT.
AAT2861-1/3: Backlight LED 7 current sink. BL7 controls the current through backlight LED 7. Connect the
cathode of backlight LED 7 to BL7. If not used, connect BL7 to OUT.
AAT2861-2: Flash LED 2 current sink. FL2 controls the current through Flash LED 2. Connect the cathode
of Flash LED 2 to FL2. If not used, connect FL2 to OUT.
Flash LED 1 current sink. FL1 controls the current through Flash LED 1. Connect the cathode of Flash LED
1 to FL1. If not used, connect FL1 to OUT.
Power ground. Connect PGND to AGND at a single point as close to the AAT2861 as possible.
Negative terminal of charge pump capacitor 2.
Negative terminal of charge pump capacitor 1.
Power input. Connect IN to the input source voltage. Bypass IN to PGND with a 2.2μF or larger ceramic
capacitor as close to the AAT2861 as possible.
Positive terminal of charge pump capacitor 1. Connect the 1μF charge pump capacitor 1 from C1+ to C1-.
Exposed paddle (bottom) Connect to PGND/AGND.
18
BL7 (FL2)
19
20
21
22
23
24
EP
FL1
PGND
C2-
C1-
IN
C1+
2
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2861.2009.02.1.2
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
