PRODUCT DATASHEET
AAT3176
TM
ChargePump
500mA LED Flash Driver IC
S2Cwire Serial Interface
DATA
Output Current (% of IMAX
)
The AAT3176 utilizes AnalogicTech’s single-wire S2Cwire
interface to enable/disable the charge pump and adjust
the output current level to one of sixteen different cur-
rent levels. Each DATA defines the output current as a
percentage of the maximum current set by the resistor
at the RSET pin, as detailed in Table 1.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
100.0%
89.1%
79.4%
70.8%
63.1%
56.2%
50.1%
44.7%
39.8%
35.5%
31.6%
28.2%
25.1%
22.4%
20.0%
7.5%
The S2Cwire interface records rising edges of the EN/SET
pin and decodes them into 16 individual current level
settings, with DATA 1 reserved for maximum current.
Once EN/SET has been held in the logic high state for
time TLAT, the programmed current is set at the current
source outputs. For subsequent current level program-
ming, the number of rising edges corresponding to the
desired DATA must be entered on the EN/SET pin. Figure
1 shows the S2CwireTM interface timing.
Table 1: Output Current at
Different S2Cwire DATA.1
When EN/SET is held low for an amount of time greater
than TOFF, the AAT3176 enters shutdown mode and draws
less than 1μA from VIN. Data and Address registers are
reset to 0 during shutdown.
S2Cwire Serial Interface Timing
THI
TOFF
TLO
TLAT
EN/SET
1
2
n-1
n ≤ 16
0
n-1
Data Reg
0
Figure 1: S2Cwire Interface Timing.
1. The flash LED accuracy is compromised at high DATA settings.
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3176.2010.01.1.1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
