PRODUCT DATASHEET
AAT3193
TM
ChargePump
3-Channel Charge-Pump LED Driver
S2Cwire Serial Interface
(AAT3193-1/-2/-3 only)
The programmed current is then seen at the current sink
outputs. When EN/SET is held low for an amount of time
longer than tOFF (500ꢀs), the AAT3193 enters into shut-
down mode and draws less than 1ꢀA from the input and
the internal data register is reset to zero.
The LED output current of the AAT3193 is controlled by
AnalogicTech’s S2Cwire serial interface. Since the LED
current is programmable, no PWM or additional control
circuitry is needed to control LED brightness. This feature
greatly reduces the burden on a microcontroller or sys-
tem IC to manage LED or display brightness, allowing the
user to “set it and forget it.” With its high-speed serial
interface (1MHz data rate), the LED current can be
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 tLAT (500ꢀs).
The AAT3193-1/2/3’s serial interface reduces the LED
current on each rising pulse of the enable input. If the
AAT3193 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 AAT3193-1.
For the AAT3193-2, Table 2 and Figure 3 illustrate an
8-step LED current control profile. For the AAT3193-3,
Table 3 and Figure 4 illustrate a 4-step LED current con-
trol profile.
THI
TOFF
TLO
TLAT
EN/SET
1
2
n-1
n ≤ 16
Data Reg
0
n-1
0
Figure 1: S2C Serial Interface Timing.
20.00
Data
EN Rising Edges
D1-D3 Current (mA)
1
2
3
4
5
1
2
3
4
5
20
18.7
17.3
16
14.7
13.3
12
15.00
10.00
5.00
6
7
6
7
8
9
8
9
10.7
9.3
8
6.7
5.3
4
2.7
1.3
0.63
0.00
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
10
11
12
13
14
15
16
10
11
12
13
14
15
16
S2Cwire Interface Data Code
Figure 2: AAT3193-1 Current Control Profile.
Table 1: AAT3193-1 LED Current Settings.
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10
3193.2008.07.1.3
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
