High Efficiency White LED Drivers
for Backlight and Keypad
Typical Characteristics
EN/SET Latch Timeout (T
LAT
) (µs)
AAT1235
EN/SET Off Timeout vs.
Supply Voltage and Temperature
EN/SET Off Timeout (T
OFF
) (µs)
400
350
300
250
EN/SET Latch Timeout vs.
Supply Voltage and Temperature
400
350
300
250
200
150
-40°C
-40°C
+85°C
200
150
100
50
2.7
+85°C
+25°C
+25°C
100
50
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Supply Voltage (V)
Supply Voltage (V)
Transition of LED Current
(Group B = 1.8mA; Group A = 20mA to 1.8mA)
4
2
4
2
Transition of LED Current
(Group B = 1.8mA to 20mA; Group A = 20mA)
EN/SET (top) (V)
EN/SET (top) (V)
0
0
I
A1
(middle) (A)
I
B1
(bottom) (A)
I
A1
(middle) (A)
I
B1
(bottom) (A)
0.02
0
0.02
0
0.02
0
0
Time (250µs/div)
Time (250µs/div)
Transition of LED Current
(Group B = 20mA; Group A = 20mA to 1.8mA)
4
2
EN/SET (top) (V)
0
I
A1
(middle) (A)
I
B1
(bottom) (A)
0.02
0
0.02
0
Time (250µs/div)
8
1235.2007.02.1.1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
