AS1101, AS1102, AS1103, AS1104
Low-Dropout LED Drivers
Data Sheet
www.austriamicrosystems.com Revision 1.5 1 - 13
1 General Description
The AS1101/AS1102/AS1103/AS1104 are LED drivers
designed to match current source bias for any color
LED, including white and blue. The devices can drive up
to 4 high-current LEDs, and the LED current is program-
mable using an external resistor (R
SET).
The AS1101 LED currents are 460 x I
SET (per LED, typ)
at an LED cathode voltage (VSAT) of 150mV and 650 x
I
SET (typ) at a VSAT of 1V, where ISET is the current
through R
SET connected to pi n CTRL.
The AS1102, AS1103, and AS1104 LED currents are
230 x I
SET (per LED, typ) at a VSAT of 150mV and 325 x
I
SET (typ) at a VSAT of 1V.
The AS1101, AS1102, and AS1104 incorporate a chip-
enable feature via pin ON. When the devices are dis-
abled, the supply current drops to less than 1µA.
The AS1101, AS1102, and AS1103 are available in a
6-pin SC70 package; the AS1104 is available in a 8-pin
MSOP package.
Figure 1. Typical Application Diagrams
2 Key Features
! LED Drivers for Parallel-Connected LEDs
! Ultra-Low Voltage Drop: Less Than 150mV (for Li-
ion Battery Support)
! Analog and PWM Brightness Control
! Up to 80mA per LED (AS1101)
! Up to 40mA per LED (AS1102, AS1103, AS1104)
! No Electromagne tic Interference, No Switching-
Noise
! Current-Matching Requires No External Compo-
nents
! Active-Low Shutdown Mode (AS1101, AS1102,
and AS1103)
! Low Shutdown-Current: Less Than 1µA
! SC70-6 Package (AS1101, AS1102, and AS1103)
! MSOP-8 Package (AS1104)
3 Applications
The AS110x devices are ideal for LED displays and key-
board backlights, as well as lighting management units
for battery powered audio devices such as MP3 and CD
players, mobile and cordless phones, PDAs, portable
DVD players, and consumer electronics.
4 Diode Control with Enable
3 Diode Control with Enable
AS1103
4 Diode Control
V
IN
AS1101
ISET
2 Diode Control with Enable
V
IN
RSET
ENABLE
VSET
(3V)
VSAT
GND
GND
CTRL
I3/I4
I1/I2
ON
I
SET
RSET
VSET
(3V)
CTRL
VSATI1 I2 I3 I4
AS1102
ISET
VIN
RSET
ENABLE
VSET
(3V)
GND
CTRL
ON
VSATI1 I2 I3
AS1104
VIN
GND
VSATI1 I2 I3 I4
ISET
RSET
ENABLE
VSET
(3V)
CTRL
ON
