AAT1142 Datasheet, PDF (16/22 Pages) Advanced Analogic Technologies – 800mA Voltage-Scaling Step-Down Converter

AAT1142
800mA Voltage-Scaling Step-Down Converter
S²Cwire Serial Interface
AnalogicTech's S²Cwire serial interface is a propri-
etary high-speed single-wire interface. The S²Cwire
interface records rising edges of the EN/SET input
and decodes them into one of 32 registers which
determines the output voltage, as shown in Table 2.
Each state corresponds to an output voltage setting.
When using the S²Cwire interface, both I²C inputs
should be tied to the ground return. This disables
the I²C functionality.
S²Cwire Serial Interface Timing
The S²Cwire serial interface has flexible timing.
Data can be clocked-in at speeds up to 1MHz.
After data has been submitted, EN/SET is held
high to latch the data for a period T_LAT. The output
is subsequently changed to the predetermined volt-
age. When EN/SET is set low for a time greater
than T_OFF, the AAT1142 is disabled. When dis-
abled, the data register is reset to the default value.
S²Cwire Timing Diagram
EN/SET
Data Reg
T_HI
T_LO
T _LAT
1
2
n-1
n ≤ 64
0
TOFF
n-1
0
S²Cwire Output Voltage Programming
The AAT1142 is programmed through the S²Cwire
interface according to Table 2. The rising clock
edges received through the EN/SET pin corre-
sponding to a given data register determine the
output voltage set-point. Upon power-up and prior
to S²Cwire programming, the default output voltage
is set to 1.8V.
Rising
Clock
Edges/
Data
Register
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Output
Voltage
(V)
No change
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
Rising
Clock
Edges/
Data
Register
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Output
Voltage
(V)
1.40
1.45
1.50
1.55
1.60
1.65
1.70
1.75
1.80 (default)
1.85
1.90
1.95
2.00
2.00
2.00
2.00
Table 2: AAT1142 S²Cwire Output Voltage
Programming Map.
16
1142.2006.07.1.0