AAT3237
300mA MicroPower™ LDO with PowerOK
General Description
The AAT3237 MicroPower low dropout (LDO) lin-
ear regulator is ideally suited for portable applica-
tions where low noise, extended battery life, and
small size are critical. The AAT3237 has been
specifically designed for low output noise perform-
ance, fast transient response, and high power sup-
ply rejection ratio (PSRR).
Other features include low quiescent current, typi-
cally 70µA, and low dropout voltage, typically less
than 400mV at full output current. The device is
output short-circuit protected and has a thermal
shutdown circuit for additional protection under
extreme conditions.
The AAT3237 also features a low-power shutdown
mode for extended battery life. A Power-OK open-
drain output signals when V
OUT
is in regulation.
The AAT3237 is available in a Pb-free, space-sav-
ing 6-pin SOT23 or 8-pin SC70JW package in 13
factory-programmed voltages: 1.2V, 1.5V, 1.8V,
2.0V, 2.3V, 2.5V, 2.7V, 2.8V, 2.85V, 2.9V, 3.0V,
3.3V, or 3.5V.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
PowerLinear
™
SmartSwitch
™
Low Dropout: 400mV at 300mA
Guaranteed 300mA Output
High Accuracy ±1.5%
70µA Quiescent Current
High Power Supply Ripple Rejection
Power-OK (POK) Output
Fast Line and Load Transient Response
Short-Circuit Protection
Over-Temperature Protection
Uses Low Equivalent Series Resistance
(ESR) Ceramic Capacitors
Shutdown Mode for Longer Battery Life
Low Temperature Coefficient
13 Factory-Programmed Output Voltages
SOT23 6-Pin or SC70JW 8-Pin Package
Applications
•
•
•
•
•
•
Cellular Phones
Desktop Computers
Digital Cameras
Notebook Computers
Personal Portable Electronics
Portable Communication Devices
Typical Application
V
IN
IN
OUT
V
OUT
AAT3237
ON/OFF
EN
GND
1µF
2.2µF
POK
POK
GND
GND
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1
AAT3237
300mA MicroPower™ LDO with PowerOK
Pin Descriptions
Pin #
SOT23-6
SC70JW-8
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.
Power-OK output. This open-drain output is low when OUT is
out of regulation. Connect a pull-up resistor from POK to OUT.
Output pin; should be decoupled with 2.2µF ceramic capacitor.
1
2, 5
3
5, 6
8
7
4
6
1
2, 3, 4
POK
OUT
Pin Configuration
SOT23-6
(Top View)
SC70JW-8
(Top View)
IN
GND
EN
1
6
OUT
GND
POK
2
5
3
4
POK
OUT
OUT
OUT
1
2
3
4
8
7
6
5
GND
EN
IN
IN
2
3237.2006.01.1.4
AAT3237
300mA MicroPower™ LDO with PowerOK
Absolute Maximum Ratings
1
T
A
= 25°C, unless otherwise noted.
Symbol
V
IN,
POK
V
ENIN(MAX)
I
OUT
T
J
T
LEAD
Description
Input Voltage, POK
Maximum EN to Input Voltage
DC Output Current
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
6
0.3
P
D
/(V
IN
- V
O
)
-40 to 150
300
Units
V
V
mA
°C
°C
Thermal Information
2
Symbol
Θ
JA
P
D
Description
Maximum Thermal Resistance (SOT23-6, SC70JW-8)
Maximum Power Dissipation (SOT23-6, SC70JW-8)
Rating
150
667
Units
°C/W
mW
Recommended Operating Conditions
Symbol
V
IN
T
Description
Input Voltage
3
Ambient Temperature Range
Rating
(V
OUT
+ V
DO
) to 5.5
-40 to +85
Units
V
°C
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-
tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on a demo board.
3. 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.
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3
AAT3237
300mA MicroPower™ LDO with PowerOK
Electrical Characteristics
V
IN
= V
OUT(NOM)
+ 1V for V
OUT
options greater than 1.5V. V
IN
= 2.5V for V
OUT
≤
1.5V. I
OUT
= 1mA, C
OUT
= 2.2µF,
C
IN
= 1µF, T
A
= -40°C 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)
V
EN(L)
V
EN(H)
I
EN
V
POK
V
POKHYS
V
POK(OL)
I
POK
PSRR
Description
Output Voltage Tolerance
Output Current
Dropout Voltage
1, 2
Short-Circuit Current
Ground Current
Shutdown Current
Line Regulation
3
Dynamic Line Regulation
Dynamic Load Regulation
Enable Threshold Low
Enable Threshold High
Leakage Current on Enable Pin
POK Trip Threshold
POK Hysteresis
POK Output Voltage Low
POK Output Leakage Current
Power Supply Rejection Ratio
Over-Temperature Shutdown
Threshold
Over-Temperature Shutdown
Hysteresis
Output Noise
Output Voltage Temperature
Coefficient
Conditions
I
OUT
= 1mA to 300mA
T
A
= 25°C
T
A
= -40 to 85°C
Min Typ Max
-1.5
-2.5
300
400
600
70
1.5
2.5
600
125
1
0.09
5
60
0.6
1.5
Units
%
mA
mV
mA
µA
µA
%/V
mV
mV
V
V
µA
% of V
OUT
% of V
OUT
V
µA
dB
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
V
EN
= 5V
V
OUT
Rising, T
A
= 25°C
I
SINK
= 1mA
V
POK
< 5.5V, V
OUT
in Regulation
1kHz
I
OUT
= 10mA
10kHz
1MHz
90
94
1
1
98
0.4
1
65
45
42
145
12
250
22
T
SD
T
HYS
e
N
TC
°C
°C
µVrms
ppm/°C
1. V
DO
is defined as V
IN
- V
OUT
when V
OUT
is 98% of nominal.
2. For V
OUT
< 2.1V, V
DO
= 2.5V - V
OUT
.
3. C
IN
= 10µF.
4
3237.2006.01.1.4
AAT3237
300mA MicroPower™ LDO with PowerOK
Typical Characteristics
Unless otherwise noted, V
IN
= 5V, T
A
= 25°C.
Dropout Voltage vs. Temperature
3.20
Dropout Characteristics
540
Dropout Voltage (mV)
480
420
360
300
240
180
120
60
0
I
L
= 300mA
Output Voltage (V)
3.00
2.80
2.60
2.40
2.20
I
OUT
= 0mA
I
L
= 150mA
I
L
= 100mA
I
OUT
= 300mA
I
OUT
= 150mA
I
OUT
= 100mA
I
OUT
= 50mA
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
2.00
2.70
2.90
3.00
3.10
3.20
3.30
Temperature (°C)
Input Voltage (V)
Dropout Voltage vs. Output Current
90.00
500
450
80.00
Ground Current vs. Input Voltage
Dropout Voltage (mV)
Ground Current (µA)
400
350
300
250
200
150
100
50
0
0
50
100
150
200
250
300
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
2
2.5
3
3.5
4
4.5
5
85°C
25°C
-40°C
I
OUT
= 300mA
I
OUT
= 0mA
I
OUT
= 150mA
I
OUT
= 50mA
I
OUT
= 10mA
Output Current (mA)
Input Voltage (V)
Quiescent Current vs. Temperature
100
Output Voltage vs. Temperature
1.203
1.202
Quiescent Current (µA)
90
Output Voltage (V)
-40 -30 -20 -10
0
10 20 30 40 50 60 70 80 90 100 110 120
80
70
60
50
40
30
20
10
0
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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