AAT2842 Datasheet, PDF (17/21 Pages) Advanced Analogic Technologies – High-Current Charge Pump with S2Cwire™ Control and Dual LDO for Backlight and Flash

AAT2842
High-Current Charge Pump with S²Cwire™
Control and Dual LDO for Backlight and Flash
Button(s) Pushed¹
DATA
LIGHT
LIGHT+DATA
MOVIE
MOVIE+DATA
FLASH
DATA+FLASH
LIGHT+MOVIE+FLASH
Description
Increment the data setting for the most recently activated mode. With backlight or
movie mode activated, hold down the button to auto-cycle through the brightness levels.
Toggle ON/OFF the backlighting section. Set the brightness level using the DATA button
(defaults to Data 1).
Decrement the brightness setting for backlight mode. Hold down to auto-cycle.
Toggle ON/OFF movie mode illumination. Set the brightness level using the DATA but-
ton (defaults to Data 10).
Decrement the brightness setting for movie mode. Hold down to auto-cycle.
Generate a flash pulse. Pulse duration is the lesser of 2 seconds or the CT value result.
Set the brightness level using the DATA button (defaults to Data 1).
Toggle ON/OFF the LDOs.
Reset. Clear all data and bring all enable lines low.
Table 4: Evaluation Board User Interface.
Evaluation Board Schematics
VOUT
D1 D2 D3 D4
D5 D6
280K yields 30mA/ch
max backlighting
280K yields 150mA/ch
max flash
R9 R10
280K 280K
CTRL_CT
C8
1.0µF
C9
1.0µF
OUTB
Programmed for
2.8V output by default
1 _BL1
2 _BSET
3 _FSET
4 _AGND
5 _CT
6 _REF
7 _FBB
R11
160K
R12
120K
C6
2.2µF
U1
AAT2842
FL3 ²¹
FL4 ²⁰
PGND ¹⁹
IN ¹⁸
C2- ¹⁷
C2+ ¹⁶
ENL ¹⁵
C2
1.0µF
C1
1.0µF
VOUT
C3
2.2µF
C5
2.2µF
R13
60.4K
R14
120K
C7
2.2µF
VIN
C4
4.7µF
ENBL
ENFL
DC+
J1
C12
321
100µF
optional 100µF
lab supply bypass
ENL
Programmed for
1.8V output by default
OUTA
Figure 4: AAT2842 Section Schematic.
1. The “+” indicates that these buttons are pressed and released together.
2842.2006.10.1.0
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