AQ1541
Low Dropout
1 Amp Voltage Regulator
with Enable Function
Product Specification
Revision 2.2
September 13, 2006
General Description
The AQ1541 is a low dropout three terminal
voltage regulator, offered in popular fixed options
or an adjustable version that can set a precise
voltage from 1.22V to 12V with two external
resistors.
It drops into the footprint of the popular LM1117
SOT-223 and provides a true fourth pin
separated from the output tab. The extra pin
allows for an
enable function
that provides a
remote turn-off for low power consumption. It
draws virtually zero current in shutdown mode.
The Enable pin implements Sequential, Ratio-
metric, or Simultaneous sequencing schemes.
To assure accuracy within 1.5% over
temperature the heart of the AQ1541 is a self-
correcting AcuRef™ bandgap reference.
On-chip current limit and thermal shutdown with
hysteresis protects against any combination of
overload and ambient temperature that might
cause the junction temperature to exceed safe
limits.
The AQ1541 is featured in the new
SOT223 4-lead
TetraPack
TM
package.
Applications
•
Graphic cards
•
PC motherboards
•
Switching power supply post-regulation
•
Telecom equipment
•
DVD video player
Features
•
Enable pin
implements sequencing
in
•
•
•
•
•
•
•
•
SOT223-3 footprint
Vout tolerance 1.5% over temperature
Eliminates expensive components
Stable with low cost 1uF capacitor
Low dropout voltage (1V at 1 Amp)
Thermal protection with hysteresis
Short circuit protection
Offered with 1.8V, 2.5V, and 3.3V fixed or
adjustable output
RoHS compliant
available
Typical Application
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AQ1541
Acutechnology Semiconductor Inc.
AQ1541
Pin Configuration
Pin Descriptions
Pin Name
V
IN
V
OUT
Ground/Adjust
E
NABLE
Function
Accepts + VCC
Regulated Output
- VCC for fixed option / Adjust pin for adjustable option
Active high, E
NABLE
> (0.5V + V
OUT
). Connect to V
IN
when not in use.
Functional Block Diagram
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Rev. 2.2
September 13, 2005
Acutechnology Semiconductor Inc.
AQ1541
Ordering Information
Device
AQ1541
AQ1541
AQ1541
AQ1541
AQ1541
AQ1541
AQ1541
AQ1541
Note:
The
Operating Tj
0C˚
≤
125C˚
0C˚
≤
125C˚
0C˚
≤
125C˚
0C˚
≤
125C˚
0C˚
≤
125C˚
0C˚
≤
125C˚
0C˚
≤
125C˚
0C˚
≤
125C˚
%Tol
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
PKG Type
SOT-223-4
SOT-223-4
SOT-223-4
SOT-223-4
SOT-223-4
SOT-223-4
SOT-223-4
SOT-223-4
V
OUT
1.8V
1.8V
2.5V
2.5V
3.3V
3.3V
ADJ
ADJ
Wrap
T&R
T&R
T&R
T&R
T&R
T&R
T&R
T&R
Ordering Number
AQ1541CY-S4-18-TR
AQ1541CY-S4-18-TRL
AQ1541CY-S4-25-TR
AQ1541CY-S4-25-TRL
AQ1541CY-S4-33-TR
AQ1541CY-S4-33-TRL
AQ1541CY-S4-AJ-TR
AQ1541CY-S4-AJ-TRL
TRL parts are Lead Free and RoHS compliant.
Absolute Maximum Ratings
Stress greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. These stress ratings only, and functional operation of the device at these or any conditions beyond
those indicated under recommended Operating Conditions is not implied. Exposure to “Absolute Maximum
Rating” for extended periods may affect device reliability. Use of standard ESD handling precautions is
required.
Parameter
Maximum V
IN
Maximum V
EN
Maximum I
EN
Power Dissipation (Internally limited)
Maximum Junction Temperature
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 sec.) TO packages
Lead Temperature (Soldering, 4sec.) SOT- 223 package
150
0 to 125
-65 to 150
300
300
°C
°C
°C
°C
°C
Value
18
18
10
Units
Volts
Volts
mA
Thermal Management
Thermal Resistance (Junction to TAB)
SOT-223
Thermal Resistance (Junction to Ambient)
SOT-223 (tab soldered to 1 in
2
1 oz. copper PCB)
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3
Typical Value
15
Typical Value
46
Rev. 2.2
Units
°C/W
Units
°C/W
September 13, 2005
Acutechnology Semiconductor Inc.
AQ1541
Electrical Specifications
Electrical characteristics are guaranteed over the full temperature range 0ºC <Tj< 125ºC. Ambient temperature
must be de-rated based upon power dissipation and package thermal characteristics. Unless otherwise
specified: V
ENABLE
= V
IN
= (V
OUT
+ 1.5V), I
OUT
= 10 mA, Tj = 25C. All values in
bold
are over the full
temperature range.
Symbol
VOUT
LNREG
LDREG
Parameter
Output Voltage
(1)
Line Regulation
(1)
Load Regulation
(1)
Conditions
Min
-1
0°C
≤Tj ≤
125°C
∆V
IN
= V
OUT
+ (1.5V to 10V)
∆I
OUT
= (10mA to 1 Amp)
I
OUT
= 100 mA
VD
Drop out Voltage
(1, 2)
I
OUT
= 500 mA
I
OUT
= 1 Amp
ISC
IQON
Current Limit
(1)
Quiescent Current ON
V
IN
-V
OUT
= 2V
V
IN
= V
ENABLE
= 5V
0°C
≤Tj ≤
125°C
V
IN
= 5V V
ENABLE
= GND
0°C
≤Tj ≤
125°C
With respect to GND
With respect to V
OUT
ENABLE
=
ENABLE
=
Typ
V
OUT
V
OUT
0.035
0.2
0.91
0.93
0.95
Max
+1
+1.5
0.2
0.4
0.95
0.95
1.0
Units
%
%
%
%
V
V
V
A
-1.5
1.1
1.5
7.5
9.0
10
0.1
0.1
0.5
1.0
mA
mA
µA
µA
V
IQOFF
VIL
VIH
IIL
IIH
VADJ
IADJ
∆
IADJ
I
QMIN
TC
TS
V
N
PSRR
TSD
TSD
HYST
Quiescent Current Off
Enable Pin Voltage (OFF)
Enable Pin Voltage (ON)
Enable Pin Current (OFF)
Enable Pin Current (ON)
Reference Voltage
Adjust Pin Current (5)
Adjust Pin Current (5)
Change
Minimum Load Current (5)
Temperature Coefficient
Temperature Stability
RMS Output Noise
(3)
Ripple Rejection Ratio
(4)
Thermal Shutdown
TSD Hysteresis
0.25
0.45
0.5
0.1
10
0.8
1.0
25
1.232
1.238
20
0.2
0.5
0.005
0.5
0.003
40
5.0
2.0
V
µA
µA
V
V
µA
µA
mA
%/°C
%/°C
%
V
OUT
dB
°C
°C
0V, V
IN
= 5V
V
IN
= 5V
1.208
1.202
Adjustable version only
0°C
≤Tj ≤
125°C
Adjustable version only
10mA
≤
I
OUT
≤
1Amp
1.4
≤
V
IN
≤
18V
To Maintain regulation
1.220
Vin = 5V
Junction Temperature
60
72
150
25
Notes:
(1) Low duty cycle pulse testing with Kelvin connections required.
(2) Measure (V
IN
- V
OUT
) when
∆V
OUT
,
OR
∆V
REF
= 1%
(3) Bandwidth of 10Hz to 10kHz
(4) 120Hz input ripple
(5) Adjustable version only
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Rev. 2.2
September 13, 2005
Acutechnology Semiconductor Inc.
AQ1541
Typical Response Curves
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5
Rev. 2.2
September 13, 2005
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