Step-Up DC/DC Converters for
White LED Backlight Applications
Electrical Characteristics
1
T
A
= -40°C to +85°C unless otherwise noted. Typical values are at 25°C, V
IN
= 3.6V.
Symbol
Power Supply
PV
IN
, V
IN
V
OUT(MAX)
I
Q
I
SHDN
I
OUT
ΔV
LINEREG(FB)
/
ΔV
IN
R
DS(ON) L
R
DS(ON) IN
T
SS
V
OVP
I
LIMIT
T
SD
T
HYS
SEL, EN/SET
V
SEL(L)
V
SEL(H)
V
EN/SET(L)
V
EN/SET(H)
T
EN/SET (LO)
T
EN/SET(HI)
T
OFF
T
LAT
I
EN/SET
AAT1231
FB
AAT1231-1
FB
FB Pin Regulation
V
IN
= 2.7V to 5.5V, SEL = GND,
EN/SET = DATA16
V
IN
= 2.7V to 5.5V, SEL = HIGH,
EN/SET = HIGH
0.09
0.564
0.1
0.6
0.11
V
0.636
AAT1231/1231-1
Description
Input Voltage Range
Maximum Output Voltage
Operating Current
Shutdown Current
Maximum Continuous Output
Current
2
Line Regulation
Low Side Switch On Resistance
Input Disconnect Switch
On Resistance
Conditions
Min
2.7
Typ
Max
5.5
24
70
1.0
50
Units
V
V
µA
µA
mA
%/V
mΩ
mΩ
µs
SEL = GND, FB = 0.1V
EN/SET = GND
2.7V < V
IN
< 5.5V, V
OUT
= 24V
V
IN
= 2.7V to 5.5V, V
FB
= 0.6V
40
0.7
80
180
300
1.1
1.2
100
2.5
140
15
1.3
From Enable to Output Regulation;
V
FB
= 300mV
Over-Voltage Protection Threshold V
OUT
Rising
Over-Voltage Hysteresis
V
OUT
Falling
N-Channel Current Limit
T
J
Thermal Shutdown Threshold
T
J
Thermal Shutdown Hysteresis
Soft-Start Time
SEL Threshold Low
SEL Threshold High
Enable Threshold Low
Enable Threshold High
EN/SET Low Time
EN/SET High Time
EN/SET Off Timeout
EN/SET Latch Timeout
EN/SET Input Leakage
V
mV
A
°C
°C
V
V
V
V
µs
µs
µs
µs
µA
0.4
1.4
0.4
V
EN/SET
V
EN/SET
V
EN/SET
V
EN/SET
V
EN/SET
<
>
<
>
=
0.6V
1.4V
0.6V
1.4V
5V V
IN
= 5V
1.4
0.3
75
75
500
500
1
0.1
0.6
0.11
-1
0.09
0.564
FB Pin Regulation
V
IN
= 2.7V to 5.5V, SEL = GND,
EN/SET = HIGH
V
IN
= 2.7V to 5.5V, SEL = HIGH,
EN/SET = DATA16
V
0.636
1. Specification over the -40°C to +85°C operating temperature range is assured by design, characterization, and correlation with statis-
tical process controls.
2. Maximum continuous output current increases with reduced output voltage, but may vary depending on operating efficiency and ther-
mal limitations.
4
1231.2007.01.1.2
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
