300mA MicroPower™ High Performance LDO
General Description
The AAT3238 MicroPower™ Low Dropout Linear
Regulator is ideally suited for portable applications
where very fast transient response, extended battery
life and small size are critical. The AAT3238 has
been specifically designed for high speed turn on and
turn off performance, fast transient response, good
power supply ripple rejection (PSRR) and is reason-
ably low noise, making it ideal for powering sensitive
circuits with fast switching requirements.
Other features include low quiescent current, typical-
ly 70µA, and low dropout voltage which is typically
less than 400mV at the maximum output current level
of 300mA. The device is output short circuit protect-
ed and has a thermal shutdown circuit for additional
protection under extreme operating conditions.
The AAT3238 also features a low-power shutdown
mode for extended battery life. A reference bypass
pin has been provided to improve PSRR perform-
ance and output noise, by connecting a small exter-
nal capacitor from the AAT3238's reference output to
ground.
The AAT3238 is available in a space saving 6-pin
SOT23 or 8-pin SC70JW package in 14 factory pro-
grammed voltages of 1.2V, 1.5V, 1.6V, 1.8V, 1.85V,
2.0V, 2.3V, 2.5V, 2.7V, 2.8V, 2.85V, 3.0V, 3.3V or
3.5V.
AAT3238
Features
•
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PowerLinear
™
Low Dropout - 400mV at 300mA
Guaranteed 300mA Output
High accuracy ±1.5%
70µA Quiescent Current
Fast line and load transient response
High speed device turn-on and shutdown
High Power Supply Ripple Rejection
Low self noise
Short circuit protection
Over-Temperature protection
Uses Low ESR ceramic capacitors
Noise reduction bypass capacitor
Shutdown mode for longer battery life
Low temperature coefficient
14 Factory programmed output voltages
SOT23 6-pin or SC70JW 8-pin package
Preliminary Information
Applications
•
•
•
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Cellular Phones
Notebook Computers
Portable Communication Devices
Personal Portable Electronics
Digital Cameras
Typical Application
V
IN
IN
OUT
V
OUT
AAT3238
ON/OFF
1µF
EN
GND
10nF
2.2µF
BYP
GND
GND
3238.2004.01.0.94
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300mA MicroPower™ High Performance LDO
Pin Descriptions
Pin #
SOT23-6
SC70JW-8
AAT3238
Symbol
IN
GND
EN
Function
Input voltage pin - should be decoupled with 1µF or greater
capacitor.
Ground connection pin
Enable pin - this pin should not be left floating. When pulled low
the PMOS pass transistor turns off and all internal circuitry
enters low-power mode, consuming less than 1µA.
Bypass capacitor connection - to improve AC ripple rejection,
connect a 10nF capacitor to GND. This will also provide a soft
start function.
Output pin - should be decoupled with 2.2µF ceramic capacitor.
1
2, 5
3
5, 6
8
7
4
1
BYP
6
2, 3, 4
OUT
Pin Configuration
SOT23-6
(Top View)
SC70JW-8
(Top View)
IN
GND
EN
1 6
2 5
3 4
OUT
GND
BYP
BYP
OUT
OUT
OUT
1
2
8
7
3
4
6
5
GND
EN
IN
IN
1
2
2
3238.2004.01.0.94
300mA MicroPower™ High Performance LDO
Absolute Maximum Ratings
Symbol
V
IN
I
OUT
T
J
AAT3238
(T
A
=25°C unless otherwise noted)
Value
6
P
D
/(V
IN
-V
O
)
-40 to 150
Description
Input Voltage
DC Output Current
Operating Junction Temperature Range
Units
V
mA
°C
Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at con-
ditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time.
Thermal Information
Symbol
Θ
JA
P
D
Description
Maximum Thermal Resistance
1
(SOT23-6, SC70JW-8)
Maximum Power Dissipation
1
(SOT23-6, SC70JW-8)
Rating
150
667
Units
°C/W
mW
Note 1: Mounted on a demo board.
Recommended Operating Conditions
Symbol
V
IN
T
Description
Input Voltage
Ambient Temperature Range
2
Rating
(V
OUT
+V
DO
) to 5.5
-40 to +85
Units
V
°C
Note 2: To calculate minimum input voltage, use the following equation: V
IN(MIN)
= V
OUT(MAX)
+ V
DO(MAX)
as long as V
IN
≥
2.5V.
3238.2004.01.0.94
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300mA MicroPower™ High Performance LDO
Electrical Characteristics
(V
IN
=V
OUT(NOM)
+1V for V
OUT
options greater than 1.5V. V
IN
= 2.5 for
V
OUT
≤1.5V.
I
OUT
=1mA, C
OUT
=2.2µF, C
IN
=1µf, T
A
= -40 to 85°C unless otherwise noted. Typical values are
T
A
=25°C)
Symbol
V
OUT
I
OUT
V
DO
I
SC
I
Q
I
SD
∆V
OUT
/
V
OUT
*∆V
IN
∆V
OUT
(line)
∆V
OUT
(load)
t
ENDLY
V
EN(L)
V
EN(H)
I
EN
PSRR
T
SD
T
HYS
e
N
TC
AAT3238
Description
Output Voltage Tolerance
Output Current
Dropout Voltage
1, 2
Short Circuit Current
Ground Current
Shutdown Current
Line Regulation
Dynamic Line Regulation
Dynamic Load Regulation
Enable Delay Time
Enable Threshold Low
Enable Threshold High
Leakage Current on Enable Pin
Power Supply Rejection Ratio
Conditions
I
OUT
= 1mA to 300mA
Min Typ Max
T
A
=25°C
-1.5
T
A
=-40 to 85°C -2.5
300
400
600
70
1.5
2.5
600
125
1
0.09
2.5
60
15
0.6
1.5
Units
%
%
mA
mV
mA
µA
µA
%/V
mV
mV
µs
V
V
µA
dB
°C
°C
µVrms/rtHz
ppm/°C
V
OUT
> 1.2V
I
OUT
= 300mA
V
OUT
< 0.4V
V
IN
= 5V, No load, EN = V
IN
V
IN
= 5V, EN = 0V
V
IN
= V
OUT
+ 1 to 5.0V
V
IN
=V
OUT
+1V to V
OUT
+2V, I
OUT
=300mA,
T
R
/T
F
=2µs
I
OUT
= 1mA to 300mA, T
R
<5µs
BYP = open
V
EN
= 5V
1 kHz
I
OUT
=10mA, C
BYP
=10nF 10kHz
1MHz
67
47
45
145
12
50
22
1
Over Temp Shutdown Threshold
Over Temp Shutdown Hysteresis
Output Noise
Noise Power BW = 300Hz-50kHz
Output Voltage Temp. Coeff.
Note 1: V
DO
is defined as V
IN
- V
OUT
when V
OUT
is 98% of nominal.
Note 2: For V
OUT
< 2.1V, V
DO
= 2.5V - V
OUT
.
4
3238.2004.01.0.94
300mA MicroPower™ High Performance LDO
Typical Characteristics
AAT3238
(Unless otherwise noted, V
IN
= 5V, T
A
= 25°C)
Dropout Voltage vs. Temperature
540
3.20
Dropout Characteristics
Dropout Voltage (mV)
480
420
I
L
= 300mA
3.00
2.80
I
OUT
= 0mA
300
240
180
120
60
0
I
L
= 150mA
I
L
= 100mA
V
OUT
(V)
360
2.60
2.40
2.20
2.00
2.70
I
OUT
= 300mA
I
OUT
= 150mA
I
OUT
= 10mA
2.80
I
L
= 50mA
-40 -30 -20 -10 0
10 20 30 40 50 60 70 80 90 100 110 120
I
OUT
= 100mA
I
OUT
= 50mA
2.90
3.00
3.10
3.20
3.30
Temperature (°C)
V
IN
(V)
Dropout Voltage vs. Output Current
500
450
90.00
80.00
70.00
60.00
Ground Current vs. Input Voltage
Dropout Voltage (mV)
400
350
I
GND
(µA)
300
250
200
150
100
50
0
0
50
85°C
25°C
-40°C
50.00
40.00
30.00
20.00
10.00
I
OUT
=300mA
I
OUT
=0mA
I
OUT
=150mA
I
OUT
=50mA
I
OUT
=10mA
100
150
200
250
300
0.00
2
2.5
3
3.5
4
4.5
5
Output Current (mA)
V
IN
(V)
Quiescent Current vs. Temperature
100
Output Voltage vs. Temperature
1.203
1.202
Quiescent Current (µA)
90
70
60
50
40
30
20
10
0
-40 -30 -20 -10
0
10 20 30 40 50 60 70 80 90 100 110 120
Output Voltage (V)
80
1.201
1.200
1.199
1.198
1.197
1.196
-40 -30 -20 -10
0
10 20
30
40
50 60
70 80
90 100
Temperature (°C)
Temperature (°C)
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