AAT3103 Datasheet, PDF (9/17 Pages) Advanced Analog Technology, Inc. – 3-Channel Charge-Pump LED Driver

ChargePump^TM
Part Number Descriptions
Part Number
AAT3103IJQ-1
AAT3103IJQ-2
AAT3103IJQ-4
Interface
S²Cwire
S²Cwire
PWM
Current Control,
Inverting
16-step
8-step
Linear
S²Cwire Serial Interface
(AAT3103-1/-2 only)
The LED output current of the AAT3103-1/-2 is controlled
by AnalogicTech’s S²Cwire serial interface. Since the LED
current is programmable, no PWM or additional control
circuitry is needed to control the LED brightness. This
feature greatly reduces the burden on a microcontroller
or system IC to manage LED or display brightness, allow-
ing the user to “set it and forget it.” With its high-speed
serial interface (1MHz data rate), the LED current can be
PRODUCT DATASHEET
AAT3103
3-Channel Charge-Pump LED Driver
changed quickly and easily. Also the non-pulsating LED
current reduces system noise and improves LED reliabil-
ity. The S²Cwire interface relies on the number of rising
edges to the EN/SET pin to set the register. A typical
write protocol is a burst of EN/SET rising edges, followed
by a pause with EN/SET held high for at least t_LAT (500μs).
The programmed current is then seen at the current
source outputs. When EN/SET is held low for an amount
of time longer than t_OFF (500μs), the AAT3103 enters into
shutdown mode and draws less than 1μA from the input
and the internal data register is reset to zero.
The AAT3103-1/-2’s serial interface reduces the LED cur-
rent on each rising pulse of the enable input. If the
AAT3103 is in shutdown, the first rising edge of the EN/
SET input turns on the LED driver to the maximum cur-
rent. Successive rising edges decrease the LED current as
shown in Table 1 and Figure 2 for the AAT3103-1. For the
AAT3103-2, Table 2 and Figure 3 illustrate an 8-step LED
current control profile. .
EN/SET
Data Reg
T_HI
T_LO
T_LAT
1
2
n-1 n ≤ 16
0
T_OFF
n-1
0
Figure 1: S²Cwire Serial Interface Timing.
S²C Data
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
EN Rising Edges
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
D1-D3 Current (mA)
20.1
18.8
17.5
16.1
14.8
13.4
12.1
10.7
9.4
8.1
6.7
5.4
4.0
2.7
1.34
0.67
Table 1: AAT3103-1 LED Current Settings,
R_SET = 14.3kΩ.
25
20
15
10
5
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
S²C Wire Interface Data Code
Figure 2: AAT3103-1 Current Control Profile,
R_SET = 14.3kΩ.
3103.2008.03.1.0
www.analogictech.com
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