AAT3238
300mA MicroPowerTM High Performance LDO
Preliminary Information
3238.2004.01.0.94
1
General Description
The AAT3238 MicroPowerTM 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 70A, 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.
Features
Low Dropout - 400mV at 300mA
Guaranteed 300mA Output
High accuracy 1.5%
70A 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
Applications
Cellular Phones
Notebook Computers
Portable Communication Devices
Personal Portable Electronics
Digital Cameras
Typical Application
AAT3238
EN
IN
OUT
BYP
GND
ON/OFF
1
F
10nF
2.2
F
V
IN
GND
GND
V
OUT
PowerLinear
TM
AAT3238
300mA MicroPowerTM High Performance LDO
2
3238.2004.01.0.94
Pin Descriptions
Pin Configuration
SOT23-6
SC70JW-8
(Top View)
(Top View)
OUT
OUT
OUT
1
2
GND
EN
IN
IN
BYP
1
2
3
4
8
7
6
5
1
2
3
BYP
EN
OUT
GND
4
6
5
GND
IN
Pin #
Symbol
Function
SOT23-6
SC70JW-8
1
5, 6
IN
Input voltage pin - should be decoupled with 1F or greater
capacitor.
2, 5
8
GND
Ground connection pin
3
7
EN
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 1A.
4
1
BYP
Bypass capacitor connection - to improve AC ripple rejection,
connect a 10nF capacitor to GND. This will also provide a soft
start function.
6
2, 3, 4
OUT
Output pin - should be decoupled with 2.2F ceramic capacitor.
Absolute Maximum Ratings
(T
A
=25C unless otherwise noted)
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
Note 1: Mounted on a demo board.
Recommended Operating Conditions
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.
Symbol
Description
Rating
Units
V
IN
Input Voltage
(V
OUT
+V
DO
) to 5.5
V
T
Ambient Temperature Range
2
-40 to +85
C
Symbol
Description
Rating
Units
JA
Maximum Thermal Resistance
1
(SOT23-6, SC70JW-8)
150
C/W
P
D
Maximum Power Dissipation
1
(SOT23-6, SC70JW-8)
667
mW
Symbol
Description
Value
Units
V
IN
Input Voltage
6
V
I
OUT
DC Output Current
P
D
/(V
IN
-V
O
)
mA
T
J
Operating Junction Temperature Range
-40 to 150
C
AAT3238
300mA MicroPowerTM High Performance LDO
3238.2004.01.0.94
3
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
=2.2F, C
IN
=1f, T
A
= -40 to 85C unless otherwise noted. Typical values are
T
A
=25C)
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
.
Symbol
Description
Conditions
Min Typ Max
Units
V
OUT
Output Voltage Tolerance
I
OUT
= 1mA to 300mA
T
A
=25C
-1.5
1.5
%
T
A
=-40 to 85C -2.5
2.5
%
I
OUT
Output Current
V
OUT
> 1.2V
300
mA
V
DO
Dropout Voltage
1, 2
I
OUT
= 300mA
400
600
mV
I
SC
Short Circuit Current
V
OUT
< 0.4V
600
mA
I
Q
Ground Current
V
IN
= 5V, No load, EN = V
IN
70
125
A
I
SD
Shutdown Current
V
IN
= 5V, EN = 0V
1
A
V
OUT
/
Line Regulation
V
IN
= V
OUT
+ 1 to 5.0V
0.09
%/V
V
OUT
*
V
IN
V
OUT
(line)
Dynamic Line Regulation
V
IN
=V
OUT
+1V to V
OUT
+2V, I
OUT
=300mA, 2.5
mV
T
R
/T
F
=2s
V
OUT
(load) Dynamic Load Regulation
I
OUT
= 1mA to 300mA, T
R
<5s
60
mV
t
ENDLY
Enable Delay Time
BYP = open
15
s
V
EN(L)
Enable Threshold Low
0.6
V
V
EN(H)
Enable Threshold High
1.5
V
I
EN
Leakage Current on Enable Pin
V
EN
= 5V
1
A
1 kHz
67
PSRR
Power Supply Rejection Ratio
I
OUT
=10mA, C
BYP
=10nF 10kHz
47
dB
1MHz
45
T
SD
Over Temp Shutdown Threshold
145
C
T
HYS
Over Temp Shutdown Hysteresis
12
C
e
N
Output Noise
Noise Power BW = 300Hz-50kHz
50
Vrms/rtHz
TC
Output Voltage Temp. Coeff.
22
ppm/C
AAT3238
300mA MicroPowerTM High Performance LDO
4
3238.2004.01.0.94
AAT3238
300mA MicroPowerTM High Performance LDO
3238.2004.01.0.94
5
Typical Characteristics
(Unless otherwise noted, V
IN
= 5V, T
A
= 25C)
Output Voltage vs. Temperature
1.196
1.197
1.198
1.199
1.200
1.201
1.202
1.203
-40 -30 -20 -10 0
10 20 30
40
50 60
70 80 90 100
Temperature (
C)
Output Voltage (V)
Quiescent Current vs. Temperature
0
10
20
30
40
50
60
70
80
90
100
-40 -30 -20 -10 0
10 20 30 40 50 60 70 80 90 100 110 120
Temperature (
C)
Quiescent Current (
A)
Ground Current vs. Input Voltage
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
2
2.5
3
3.5
4.5
4
5
V
IN
(V)
I
GND
(
A)
I
OUT
=0mA
I
OUT
=10mA
I
OUT
=50mA
I
OUT
=150mA
I
OUT
=300mA
Dropout Voltage vs. Output Current
0
50
100
150
200
250
300
350
400
450
500
0
50
100
150
200
250
300
Output Current (mA)
Dropout Voltage (mV)
85
C
25
C
-40
C
Dropout Characteristics
2.00
2.20
2.40
2.60
2.80
3.00
3.20
2.70
2.80
2.90
3.00
3.10
3.20
3.30
V
IN
(V)
V
OUT
(V)
I
OUT
= 300mA
I
OUT
= 150mA
I
OUT
= 100mA
I
OUT
= 50mA
I
OUT
= 10mA
I
OUT
= 0mA
Dropout Voltage vs. Temperature
0
60
120
180
240
300
360
420
480
540
-40 -30 -20 -10 0
10 20 30 40 50 60 70 80 90 100 110 120
Temperature (
C)
Dropout Voltage (mV)
I
L
= 300mA
I
L
= 150mA
I
L
= 100mA
I
L
= 50mA
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