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 (RSET).
The AS1101 LED currents are 460 x ISET (per LED, typ)
at an LED cathode voltage (VSAT) of 150mV and 650 x
ISET (typ) at a VSAT of 1V, where ISET is the current
through RSET connected to pin CTRL.
The AS1102, AS1103, and AS1104 LED currents are
230 x ISET (per LED, typ) at a VSAT of 150mV and 325 x
ISET (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
VIN
AS1101
ISET
2 Diode Control with Enable
VIN
RSET
ENABLE
VSET
(3V)
VSAT
GND
GND
CTRL
I3/I4
I1/I2
ON
ISET
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
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Pinout
4 Pinout
Pin Assignments
Figure 2. Pin Assignments – (Top View)
Pin Descriptions
Table 1. Pin Descriptio ns
Pin Number Pin Name Description
(see Figure 2)
CTRL Sets LED current; connect to external resistor.
I1 Connect to cathode of LED.
I2 Connect to cathode of LED.
I3 Connect to cathode of LED.
I4 Connect to cathode of LED.
GND Ground
ON Device Enable Input.
CTRL
I2
I1
I3
I4
GND
1
2
3
8
7
6
ON
I3
I4
N/C
CTRL
I2
AS1104
CTRL
I2
I1
ON
I3
GND
1
2
3
6
5
4
CTRL
I1/I2
N/C
ON
I3/I4
GND
AS1101
5I14GND
8-Pin MSOP
6-Pin SC70
1
2
3
6
5
4
AS1102
1
2
3
6
5
4
AS1103
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Absolute Maximum Ratings
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.
† The reflow peak soldering temperature (bod y tempera ture) is specified according to IPC/JEDEC J-STD-020C “Mois-
ture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices”.
Operating Conditions
† Not applicable to AS1103.
Table 2. Absolute Maximum Ratings
Parameter Min Max Unit Comment
VI1, VI2, VI3, VI4, CTRL and ON Voltage to GND -0.3 5 V
Power Dissipated by Device at TAMB = 85°C 200 mW SC70-6
250 mW MSOP-8
I1, I2, I3, I4 Steady State Current 100 mA
Package Body Temperature † 260 ºC
Junction Temperature 150 ºC
Sto rage Temperature -65 150 ºC
Electrostatic Discharge Protection (ESD) Level 2 kV Human Body Model;
Norm: MIL-STD883E 3015 methods.
Table 3. Recommended Operatin g Conditions
Parameter Min Typ Max Unit Comments
LED Cathode Voltage 0.15 0.6 3.6 V
Enable Voltage ON Mode † 2.2 3.0 3.6 V
Enable Voltage OFF Mode † 00.20.5V
Ambient Temperature -40 25 85 ºC
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Electrical Characteristics
6 Electrical Characteristics
AS1101 Electrical Characteristics
TAMB = 25°C (unless otherwise noted).
† Efficiency = (VIN - VSAT)/VIN. Informati on parameter, guaranteed by design.
AS1102, AS1103, AS1104 Electrical Characteristics
TAMB = 25°C (unless otherwise noted).
Table 4. Electrical Characteristics – AS1101
Parameter Symbol Conditions Min Typ Max Units
ISET Range ISET VON = 3V 25 150 µA
Output Current Multiplication Ratio OCMR ISET = 25µA, VSAT = 150mV, VON = 3V 350 500 650
Output Current Multiplication Ratio OCMR ISET = 40µA, VSAT = 150mV, VON = 3V 335 480 625
Output Current Multiplication Ratio OCMR ISET = 75µA, VSAT = 150mV, VON = 3V 295 420 545
Output Current Multiplication Ratio OCMR ISET = 25µA, VSAT = 600mV, VON = 3V 435 620 805
Output Current Multiplication Ratio OCMR ISET = 40µA, VSAT = 600mV, VON = 3V 425 610 795
Output Current Multiplication Ratio OCMR ISET = 75µA, VSAT = 600mV, VON = 3V 415 590 765
Output Current Multiplication Ratio OCMR ISET = 25µA, VSAT = 1000mV, VON = 3V 470 670 870
Output Current Multiplication Ratio OCMR ISET = 40µA, VSAT = 1000mV, VON = 3V 460 660 860
Output Current Multiplication Ratio OCMR ISET = 75µA, VSAT = 1000mV, VON = 3V 440 630 820
LED-to-LED Current Matching Match VON = 3V -3 3 %
ISET in OFF Mode ISET,OFF VCTRL = 3V, VSAT = 3V, VON = 0V 0.1 1 µA
IIN in OFF Mode IIN,OFF
VCTRL = 3V, VSAT = 3V, VON = 0V,
TAMB = 25ºC 0.1 1 µA
VCTRL = 3V, V SAT = 3V, VON = 0V 4
Peak Efficiency †ηVIN = 3V, VON = 3V 95 %
Table 5. Electrical Characte ristics – AS1102, AS1103, AS1104
Parameter Symbol Conditions Min Typ Max Units
ISET Range ISET VON = 3V 25 150 µA
Output Current Multiplication Ratio OCMR ISET = 25µA, VSAT = 150mV, VON = 3V 175 250 325
Output Current Multiplication Ratio OCMR ISET = 40µA, VSAT = 150mV, VON = 3V 170 240 310
Output Current Multiplication Ratio OCMR ISET = 75µA, VSAT = 150mV, VON = 3V 145 210 275
Output Current Multiplication Ratio OCMR ISET = 25µA, VSAT = 600mV, VON = 3V 215 310 405
Output Current Multiplication Ratio OCMR ISET = 40µA, VSAT = 600mV, VON = 3V 215 305 395
Output Current Multiplication Ratio OCMR ISET = 75µA, VSAT = 600mV, VON = 3V 205 295 385
Output Current Multiplication Ratio OCMR ISET = 25µA, VSAT = 1000mV, VON = 3V 235 335 435
Output Current Multiplication Ratio OCMR ISET = 40µA, VSAT = 1000mV, VON = 3V 230 330 430
Output Current Multiplication Ratio OCMR ISET = 75µA, VSAT = 1000mV, VON = 3V 220 315 410
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Electrical Characteristics
LED-to-LED Current Matching Match VON = 3V -3 3 %
ISET in OFF Mode 1ISET,OFF VCTRL = 3V, VSAT = 3V, VON = 0V 0.1 1 µA
IIN in OFF Mode 1IIN,OFF
VCTRL = 3V, VSAT = 3V, VON = 0V,
TAMB = 25°C 0.1 1 µA
VCTRL = 3V, V SAT = 3V, VON = 0V 2
Peak Efficiency 2 ηVIN = 3V, VON = 3V 95 %
1. Not applicable to AS1103.
2. Efficiency = (VIN - VSAT) / VIN. Information parameter, guaranteed by design.
Table 5. Electrical Characte ristics – AS1102, AS1103, AS1104
Parameter Symbol Conditions Min Typ Max Units
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Typical Pe rformance Chara cteristics
7 Typical Performance Characteristics
Figure 3. Set Current vs. VCTRL Figure 4. Set Current vs.VSET; RSET = 30kΩ
Figure 5. AS1101 ILED vs. VSAT Figure 6. AS1102, AS1103, AS1104 ILED vs. VSAT
Figure 7. AS1101 OMCR vs. ISET Figure 8. AS1102, AS1103, AS1104 OMCR vs. ISET
0
10
20
30
40
50
60
70
80
90
100
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
VCTRL (V)
ISET (µA) e
0
10
20
30
40
50
60
70
80
90
100
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
VSET (V)
ISET (µA) e
5
10
15
20
25
30
0.0 0.2 0.4 0.6 0.8 1.0
VSAT (V)
ILED (mA) e
5
10
15
20
25
30
35
0.0 0.2 0.4 0.6 0.8 1.0
VSAT (V)
ILED (mA) e
ISET = 50µA
ISET = 25µA
ISET = 100µA
ISET = 50µA
ISET = 25µA
0
100
200
300
400
500
600
700
0 20 40 60 80 100 120 140 160
ISET (µA)
OCMR
0
50
100
150
200
250
300
350
0 20 40 60 80 100 120 140 160
ISET (µA)
OCMR
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Typical Performa nce Characteristic s
Figure 9. AS1102, AS1103, AS1104 ILED vs. RSET, Figure 10. AS1102, AS1103, AS1104 ILED vs. RSET;
VSET = 3V VSET = 3V
Figure 11. AS1101 ILED vs. RSET; VSET = 3V Figure 12. ILED vs. Temp; VLED = -0.25V, ISET = 50µA
Figure 13. AS1101 ILED vs. ISET Figure 14. AS1102, AS1103, AS1104 ILED vs. ISET
4
6
8
10
12
14
16
18
20
22
0 20 40 60 80 100 120 140 160
RSET (kΩ)
ILED (mA) e
0
5
10
15
20
25
30
35
0 20406080100120140160180200
RSET (kΩ)
ILED (mA) e
VSAT = 0.6V
VSAT = 0.3V
VSAT = 0.5V
VSAT = 0.4V
VSAT = 1V
VSAT = 0.15V
VSAT = 0.6V
VSAT = 0.3V
4
6
8
10
12
14
16
18
20
22
0 20 40 60 80 100 120 140 160
RSET (kΩ)
ILED (mA) e
VSAT = 0.6V
VSAT = 0.3V
VSAT = 0.5V
VSAT = 0.4V
2
4
6
8
10
12
14
16
18
20
22
10 20 30 40 50 60 70 80 90 100
RSET (kΩ)
ILED (mA) e
VSAT = 0.30V
VSAT = 0.05VVSAT = 0.10V
VSAT = 0.15V
VSAT = 0.20V
VSAT = 0.25V
11
11.5
12
12.5
13
-40 -20 0 20 40 60 80 100
Temperature (°C)
ILED (mA) e
0
10
20
30
40
50
60
70
80
90
0 20 40 60 80 100 120 140 160
ISET (µA)
ILED (mA) e
0
5
10
15
20
25
30
35
40
45
0 20 40 60 80 100 120 140 160
ISET (µA)
ILED (mA) e
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Typical Performa nce Characteristic s
Figure 15. AS1101 vs. RSET Figure 16. AS1102, AS1103, AS110 4 ILED vs. VIN
Figure 17. Control Volt age Transient Response Figure 18. Enable Voltage Transient Response
0
10
20
30
40
50
60
3.0 3.5 4.0 4.5 5.0
VIN (V)
ILED (mA) e
0
10
20
30
40
50
60
3.0 3.5 4.0 4.5 5.0
VIN (V)
ILED (mA) e
LED Type 1
LED Type 2
AS11011
RSET
CTRL Voltage
2V/Div 10mA/Div
Enable Voltage
2V/Div 10mA/Div
LED Current
LED Current
1µs/Div 1µs/Div
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Applicatio n In formation
8 Application Information
Figure 19. Typical Application Diagrams
Setting the LED Current
The current going into the LEDs is approximately OCMR times greater then the current ISET. LED current is controlled
by VSET and RSET (see Figure 19) according to the formula:
ILED = OCMR x (VSET - VCTRL)/RSET (EQ 1)
For VSET = 3V and a specific LED current, the value of RSET can be determined using the graphs shown in Figure 9,
Figure 10, and Figure 11 on page 7. For any other option, the value of ISET can be determined using the graph in
Figure 3 on page 6.
Note: LED brightness can also be adjusted by driving pin ENABLE or pin CTRL with a PWM signal.
4 Diode Control with Enable
3 Diode Control with Enable
AS1103
4 Diode Control
VIN
AS1101
ISET
2 Diode Control with Enable
VIN
RSET
ENABLE
VSET
(3V)
VSAT
GND
GND
CTRL
I3/I4
I1/I2
ON
ISET
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
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Package Drawings and Markings
9 Package Drawings and Markings
Figure 20. SC70-6 Package
Notes:
1. All dimensions are in millimeters.
2. Dimensions are inclusive of plating.
3. Dimensions are exclusive of mold f lash and metal burrs.
4. All specifications comply with JEITA SC88 and JEDEC-MO-203.
Symbol Min Max
e 0.65 BSC
D 1.80 2.20
b 0.15 0.30
E 1.15 1.35
HE 1.80 2.40
Q1 0.10 0.40
A2 0.80 1.00
A1 0.00 0.10
A 0.80 1.10
c 0.10 0.18
L 0.10 0.30
Lj 0.26 0.46
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Package Drawings and Markings
Figure 21. MSOP-8 Package
Symbol Millimeters ± Tolerance Symbol Millimeters ± Tolerance
A 1.10 Max b 0.33 +0.07 to -0.08
A1 0.10 ±0.05 b1 0.30 ±0.05
A2 0.86 ±0.08 c 0.18 ±0.05
D 3.00 ±0.10 c1 0.15 +0.03 t o -0.02
D2 2.95 ±0.10 θ1 3.0º ±3.0º
E4.90 ±0.15 θ2 12.0º ±3.0º
E1 3.00 ±0.10 θ3 12.0º ±3.0º
E2 2.95 ±0.10 L 0.55 ±0.15
E3 0.51 ±0.13 L1 0.95 BSC
E4 0.51 ±0.13 aaa 0.10
R 0.15 +0.15 to -0.08 bbb 0.08
R1 0.15 +0.15 to -0.08 ccc 0.25
t1 0.31 ±0.08 e .65 BSC
t2 0.41 ±0.08 S .525 BSC
Notes:
1. All dimensions are in millimeters (angle in degrees), unless otherwise specified.
2. Datums B and C to be determined at datum plane H.
3. Dimensions D and E1 are to be determined at dat um plane H.
4. Dimensions D2 and E2 are for top package and D and E1 are for bottom package.
5. Cross section A-A to be determined at 0.13 to 0.25mm from the lead tip.
6. Dimensions D and D2 do not include mold flash, protrusion, or gate burrs.
7. Dimension E1 and E2 do not include interl ead flash or protrusion.
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AS1101/AS1102/AS1103/AS1104
Data Sheet - Ordering Information
10 Ordering Information
Part Number Marking Description Package Type Delivery Form
AS1101-T JO1 Dual LED driver with enable. SC70-6 Tape and ReelAS1102-T JO2 Triple LED driver with enable.
AS1103-T JO3 Quad LED driver.
AS1104-T JO4 Quad LED driver with enable. MSOP-8 Tape and Re el
AS1104 Tubes
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AS1101/AS1102/AS1103/AS1104
Data Sheet
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Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe.
Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapt ed, merged, trans-
lated, stored, or used without the prior written consent of the copyright owner.
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Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing
in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding
the information set forth herein or regarding the freedom of the described devices from patent infringement. austriami-
crosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior
to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information.
This product is intended for use in normal commercial a pplications. Applicati ons requiring extended temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-
sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for
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production flow, such as test flow or test locatio n.
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