High Efficiency White LED Drivers
for Backlight and Keypad
Electrical Characteristics
1
V
IN
= 3.6V; C
IN
= 2.2µF;T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= 25°C.
Symbol
Power Supply
V
IN
V
OUT(MAX)
V
UVLO
I
CC
I
SHDN(MAX)
I
OX
I
DX
I
DX-Matching
T
SS
V
OV
AAT1235
Description
Input Voltage Range
Maximum Output Voltage
UVLO Threshold
Operating Current (No Switching)
IN Pin Shutdown Current
Maximum Continuous Output Current
Current Sink Accuracy
Current Matching Between Any
Sink Channels
Soft-Start Time
OVP Threshold Voltage
OVP Threshold Hysteresis
Low Side Switch On Resistance
Input Disconnect Switch
Current Set Ratio
Input Switch Current Limit
Conditions
Min
2.7
Typ
Max Units
5.5
24
2.7
V
V
V
mV
V
µA
µA
mA
mA
%
µs
1.3
V
mV
mΩ
mΩ
A/A
A
V
V
µs
µs
µs
µs
µA
°C
°C
V
IN
Rising
Hysteresis
V
IN
Falling
B1 = B2 = A1 = A2 = A3 = 1.2V,
2mA Setting, R
SET
= 226kΩ
EN = GND
V
O
= 24V
R
SET
= 22.6kΩ
R
SET
= 22.6kΩ,
A1 = A2 = A3 = B1 = B2 = 0.4V
From Enable to Output
Regulation; V
FB
= 300mV
V
OUT
Rising
I
OUT
= 100mA
I
OUT
= 100mA
I
SINK
/I
RSET
, V
RSET
= 0.6V
150
1.8
300
1.0
100
18
20
2
300
1.1
1.2
100
80
200
760
22
5
R
DS(ON)N
R
DS(ON)IN
I
SET
I
LIMIT
EN/SET Input
V
EN(L)
Enable Threshold Low
V
EN(H)
Enable Threshold High
T
EN/SET LO
EN/SET Low Time
T
EN/SET HI
EN/SET High Time
T
OFF
EN/SET Off Timeout
T
LAT
EN/SET Latch Timeout
I
EN/SET
EN/SET Input Leakage
Thermal Protection
T
J-TH
T
J
Thermal Shutdown Threshold
T
J-HYS
T
J
Thermal Shutdown Hysteresis
1.2
0.4
1.4
0.3
75
75
500
500
1
140
15
V
EN/SET
= V
IN
= 5V
-1
1. The AAT1235 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range is assured by
design, characterization, and correlation with statistical process controls.
4
1235.2007.02.1.1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
