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The technical content of this austriamicrosystems datasheet is still valid.
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A S 11 0 1 , A S 11 0 2 , A S 11 0 3 , A S 11 0 4
Low-Dropout LED Drivers
Data Sheet
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 (V
SAT
) of 150mV and 650 x
I
SET
(typ) at a V
SAT
of 1V, where I
SET
is the current
through R
SET
connected to pin CTRL.
2 Key Features
!
!
LED Drivers for Parallel-Connected LEDs
!
!
!
!
Analog and PWM Brightness Control
Up to 80mA per LED (AS1101)
Up to 40mA per LED (AS1102, AS1103, AS1104)
No Electromagnetic Interference, No Switching-
Noise
The AS1102, AS1103, and AS1104 LED currents are
230 x I
SET
(per LED, typ) at a V
SAT
of 150mV and 325 x
I
SET
(typ) at a V
SAT
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 Diode Control with Enable
V
IN
I1/I2 V
SAT
I
SET
V
SET
(3V)
R
SET
CTRL
ON
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ENABLE
V
IN
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I1 V
SAT
I2
I
SET
V
SET
(3V)
R
SET
CTRL
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Current-Matching Requires No External Compo-
nents
Active-Low Shutdown Mode (AS1101, AS1102,
and AS1103)
Low Shutdown-Current: Less Than 1µA
MSOP-8 Package (AS1104)
!
!
!
!
SC70-6 Package (AS1101, AS1102, and AS1103)
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.
3 Diode Control with Enable
V
IN
I3/I4
I1 V
SAT
I2
I3
I
SET
AS1101
V
SET
(3V)
R
SET
CTRL
ON
AS1102
GND
ENABLE
GND
4 Diode Control
4 Diode Control with Enable
V
IN
I3
I4
I
SET
V
SET
(3V)
I1 V
SAT
I2
I3
I4
AS1103
GND
R
SET
CTRL
ON
AS1104
GND
ENABLE
Revision 1.5
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Ultra-Low Voltage Drop: Less Than 150mV (for Li-
ion Battery Support)
AS1101/AS1102/AS1103/AS1104
Data Sheet
- P i n o u t
4 Pinout
Pin Assignments
Figure 2. Pin Assignments – (Top View)
I1/I2
N/C
2
AS1101
5
I3/I4
GND
I2
I1
2
AS1102
5
I3
GND
I2
I1
2
AS1103
3
4
3
4
3
Pin Descriptions
Pin Number
Table 1. Pin Descriptions
(see Figure 2)
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6-Pin SC70
ON
1
8
N/C
I3
I4
2
7
CTRL
I2
AS1104
3
4
6
5
GND
I1
8-Pin MSOP
Pin Name
CTRL
I1
I2
I3
I4
Description
Sets LED current; connect to external resistor.
Connect to cathode of LED.
Connect to cathode of LED.
Connect to cathode of LED.
Connect to cathode of LED.
Ground
Device Enable Input.
GND
ON
Revision 1.5
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5
I4
4
GND
CTRL
1
6
ON
CTRL
1
6
ON
CTRL
1
6
I3
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AS1101/AS1102/AS1103/AS1104
Data Sheet
- A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in
Table 2
may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those listed in
Electrical Characteristics
on page 4
is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reli-
ability.
Table 2. Absolute Maximum Ratings
V
I1
, V
I2
, V
I3
, V
I4
, CTRL and ON Voltage to GND
Power Dissipated by Device at T
AMB
= 85°C
I1, I2, I3, I4 Steady State Current
Package Body Temperature
Junction Temperature
Storage Temperature
†
-0.3
5
200
250
100
V
mW
mW
mA
ºC
SC70-6
MSOP-8
Electrostatic Discharge Protection (ESD) Level
†
The reflow peak soldering temperature (body temperature) is specified according to
IPC/JEDEC J-STD-020C “Mois-
ture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices”.
Operating Conditions
Parameter
Table 3. Recommended Operating Conditions
LED Cathode Voltage
Enable Voltage ON Mode
Enable Voltage OFF Mode
Ambient Temperature
†
Not applicable to AS1103.
Te
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150
ºC
-65
2
150
ºC
kV
Human Body Model;
Norm: MIL-STD883E 3015
methods.
Min
Typ
0.6
Max
3.6
Unit
V
Comments
0.15
2.2
0
†
3.0
3.6
V
†
0.2
25
0.5
85
V
-40
ºC
Revision 1.5
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Parameter
Min
Max
Unit
Comment
AS1101/AS1102/AS1103/AS1104
Data Sheet
- E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
AS1101 Electrical Characteristics
T
AMB
= 25°C (unless otherwise noted).
Table 4. Electrical Characteristics – AS1101
Parameter
I
SET
Range
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
LED-to-LED Current Matching
I
SET
in OFF Mode
Symbol
I
SET
OCMR
OCMR
OCMR
OCMR
OCMR
OCMR
OCMR
OCMR
OCMR
Match
Conditions
V
ON
= 3V
I
SET
= 25µA, V
SAT
= 150mV, V
ON
= 3V
I
SET
= 40µA, V
SAT
= 150mV, V
ON
= 3V
I
SET
= 75µA, V
SAT
= 150mV, V
ON
= 3V
I
SET
= 25µA, V
SAT
= 600mV, V
ON
= 3V
I
SET
= 40µA, V
SAT
= 600mV, V
ON
= 3V
I
SET
= 75µA, V
SAT
= 600mV, V
ON
= 3V
Min
25
350
335
295
435
425
415
Typ
Max Units
150
µA
500
480
420
620
610
590
I
IN
in OFF Mode
Peak Efficiency
†
Efficiency = (V
IN
- V
SAT
)/V
IN
. Information parameter, guaranteed by design.
AS1102, AS1103, AS1104 Electrical Characteristics
T
AMB
= 25°C (unless otherwise noted).
ch
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Table 5. Electrical Characteristics – AS1102, AS1103
,
AS1104
Parameter
Symbol
I
SET
I
SET
Range
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Te
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
Output Current Multiplication Ratio
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795
765
I
SET
= 25µA, V
SAT
= 1000mV, V
ON
= 3V
470
460
440
-3
670
660
630
870
860
820
3
I
SET
= 40µA, V
SAT
= 1000mV, V
ON
= 3V
I
SET
= 75µA, V
SAT
= 1000mV, V
ON
= 3V
V
ON
= 3V
I
SET,OFF
V
CTRL
= 3V, V
SAT
= 3V, V
ON
= 0V
0.1
1
I
IN,OFF
V
CTRL
= 3V, V
SAT
= 3V, V
ON
= 0V,
T
AMB
= 25ºC
V
CTRL
= 3V, V
SAT
= 3V, V
ON
= 0V
V
IN
= 3V, V
ON
= 3V
0.1
1
4
†
η
95
Conditions
V
ON
= 3V
I
SET
= 25µA, V
SAT
= 150mV, V
ON
= 3V
I
SET
= 40µA, V
SAT
= 150mV, V
ON
= 3V
I
SET
= 75µA, V
SAT
= 150mV, V
ON
= 3V
I
SET
= 25µA, V
SAT
= 600mV, V
ON
= 3V
I
SET
= 40µA, V
SAT
= 600mV, V
ON
= 3V
I
SET
= 75µA, V
SAT
= 600mV, V
ON
= 3V
I
SET
= 25µA, V
SAT
= 1000mV, V
ON
= 3V
I
SET
= 40µA, V
SAT
= 1000mV, V
ON
= 3V
I
SET
= 75µA, V
SAT
= 1000mV, V
ON
= 3V
Revision 1.5
Min
25
175
170
145
215
215
205
235
230
220
Typ
OCMR
OCMR
OCMR
OCMR
OCMR
OCMR
OCMR
OCMR
OCMR
250
240
210
310
305
295
335
330
315
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650
625
545
%
µA
µA
%
Max Units
150
325
310
275
405
395
385
435
430
410
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µA
