AAT3237IJS-3.3-T1 [ANALOGICTECH]
300mA MicroPower⑩ LDO with PowerOK; 300毫安微功率LDO ™与PowerOK
| 型号： | AAT3237IJS-3.3-T1 |
| 厂家： | 
ADVANCED ANALOGIC TECHNOLOGIES |
| 描述： | 300mA MicroPower⑩ LDO with PowerOK |
| 文件： | 总13页 (文件大小：162K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AAT3237
300mA MicroPower™ LDO with PowerOK
™
PowerLinear
General Description
Features
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).
•
•
•
•
•
•
•
•
•
•
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
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 VOUT 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.
Applications
•
•
•
•
•
•
Cellular Phones
Desktop Computers
Digital Cameras
Notebook Computers
Personal Portable Electronics
Portable Communication Devices
Typical Application
VIN
VOUT
POK
IN
OUT
POK
AAT3237
ON/OFF
EN
GND
1µF
2.2µF
GND
GND
3237.2006.01.1.4
1
AAT3237
300mA MicroPower™ LDO with PowerOK
Pin Descriptions
Pin #
Symbol
Function
SOT23-6
SC70JW-8
1
5, 6
IN
Input voltage pin; should be decoupled with 1µF or greater
capacitor.
2, 5
3
8
7
GND
EN
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.
4
6
1
POK
OUT
Power-OK output. This open-drain output is low when OUT is
out of regulation. Connect a pull-up resistor from POK to OUT.
2, 3, 4
Output pin; should be decoupled with 2.2µF ceramic capacitor.
Pin Configuration
SOT23-6
(Top View)
SC70JW-8
(Top View)
6
1
OUT
GND
POK
IN
GND
EN
8
7
6
5
1
2
3
4
GND
EN
IN
POK
OUT
OUT
OUT
2
3
5
4
IN
2
3237.2006.01.1.4
AAT3237
300mA MicroPower™ LDO with PowerOK
Absolute Maximum Ratings1
TA = 25°C, unless otherwise noted.
Symbol
Description
Value
Units
VIN, POK
VENIN(MAX)
IOUT
Input Voltage, POK
6
0.3
V
V
Maximum EN to Input Voltage
DC Output Current
PD/(VIN - VO)
-40 to 150
300
mA
°C
°C
TJ
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
TLEAD
Thermal Information2
Symbol
Description
Rating
Units
ΘJA
PD
Maximum Thermal Resistance (SOT23-6, SC70JW-8)
Maximum Power Dissipation (SOT23-6, SC70JW-8)
150
667
°C/W
mW
Recommended Operating Conditions
Symbol
Description
Rating
Units
VIN
T
Input Voltage3
(VOUT + VDO) to 5.5
-40 to +85
V
Ambient Temperature Range
°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: VIN(MIN) = VOUT(MAX) + VDO(MAX) as long as VIN ≥ 2.5V.
3237.2006.01.1.4
3
AAT3237
300mA MicroPower™ LDO with PowerOK
Electrical Characteristics
VIN = VOUT(NOM) + 1V for VOUT options greater than 1.5V. VIN = 2.5V for VOUT ≤ 1.5V. IOUT = 1mA, COUT = 2.2µF,
CIN = 1µF, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol
Description
Conditions
Min Typ Max Units
TA = 25°C
-1.5
1.5
2.5
VOUT
Output Voltage Tolerance
IOUT = 1mA to 300mA
%
TA = -40 to 85°C -2.5
300
IOUT
VDO
ISC
IQ
Output Current
VOUT > 1.2V
IOUT = 300mA
VOUT < 0.4V
mA
mV
mA
µA
Dropout Voltage 1, 2
Short-Circuit Current
Ground Current
400 600
600
VIN = 5V, No Load, EN = VIN
VIN = 5V, EN = 0V
70
125
1
ISD
Shutdown Current
µA
∆VOUT
VOUT*∆VIN
/
Line Regulation 3
VIN = VOUT + 1 to 5.0V
0.09
%/V
mV
VIN = VOUT + 1V to VOUT + 2V,
∆VOUT(line)
Dynamic Line Regulation
5
IOUT = 300mA, TR/TF = 2µs
∆VOUT(load)
VEN(L)
Dynamic Load Regulation
Enable Threshold Low
Enable Threshold High
Leakage Current on Enable Pin
POK Trip Threshold
IOUT = 1mA to 300mA, TR <5µs
60
mV
V
0.6
1
VEN(H)
IEN
1.5
V
VEN = 5V
µA
VPOK
VOUT Rising, TA = 25°C
90 94
1
98 % of VOUT
% of VOUT
VPOKHYS
VPOK(OL)
IPOK
POK Hysteresis
POK Output Voltage Low
POK Output Leakage Current
ISINK = 1mA
0.4
1
V
VPOK < 5.5V, VOUT in Regulation
1kHz
µA
65
45
42
PSRR
TSD
Power Supply Rejection Ratio
IOUT = 10mA
10kHz
1MHz
dB
°C
Over-Temperature Shutdown
Threshold
145
Over-Temperature Shutdown
Hysteresis
THYS
eN
12
250
22
°C
Output Noise
µVrms
ppm/°C
Output Voltage Temperature
Coefficient
TC
1. VDO is defined as VIN - VOUT when VOUT is 98% of nominal.
2. For VOUT < 2.1V, VDO = 2.5V - VOUT
3. CIN = 10µF.
.
4
3237.2006.01.1.4
AAT3237
300mA MicroPower™ LDO with PowerOK
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA = 25°C.
Dropout Characteristics
Dropout Voltage vs. Temperature
3.20
540
3.00
IOUT = 0mA
480
IL = 300mA
420
360
2.80
IOUT = 300mA
IOUT = 150mA
2.60
300
IL = 100mA
IL = 150mA
240
2.40
IOUT = 100mA
180
120
IOUT = 50mA
2.20
IOUT = 10mA
60
IL = 50mA
2.00
0
2.70
2.80
2.90
3.00
3.10
3.20
3.30
-40 -30 -20 -10
0
10 20 30 40 50 60 70 80 90 100 110 120
Input Voltage (V)
Temperature (°C)
Ground Current vs. Input Voltage
Dropout Voltage vs. Output Current
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
500
450
400
350
300
250
200
150
100
50
IOUT = 300mA
85°C
IOUT = 150mA
IOUT = 50mA
25°C
IOUT = 0mA
IOUT = 10mA
-40°C
0
0
50
100
150
200
250
300
2
2.5
3
3.5
4
4.5
5
Input Voltage (V)
Output Current (mA)
Output Voltage vs. Temperature
Quiescent Current vs. Temperature
1.203
1.202
1.201
1.200
1.199
1.198
1.197
1.196
100
90
80
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
-40 -30 -20 -10
0
10 20 30 40 50 60 70 80 90 100
Temperature (°C)
Temperature (°C)
3237.2006.01.1.4
5
AAT3237
300mA MicroPower™ LDO with PowerOK
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA = 25°C.
Turn-On Time and POK Delay
Turn-Off Time with POK Delay
VENABLE (2V/div)
VEN (2V/div)
VPOK (2V/div)
VOUT (500mV/div)
VPOK (500mV/div)
VOUT (2V/div)
Time (200µs/div)
Time (10µs/div)
Line Transient Response
POK Output Response
VIN (2V/div)
6
3.25
5
3.20
VIN
4
3
2
1
3.15
VOUT (2V/div)
3.10
3.05
3.00
2.95
VOUT
0
VPOK (1V/div)
-1
2.90
-2
2.85
Time (200µs/div)
Time (100µs/div)
Load Transient Response 300mA
Load Transient Response
3.00
2.90
2.80
2.70
2.60
2.50
2.40
2.30
2.20
2.10
800
700
600
500
400
300
200
100
0
2.90
500
400
300
200
100
0
2.85
VOUT
VOUT
2.80
2.75
2.70
IOUT
IOUT
2.65
2.60
-100
-100
Time (100µs/div)
Time (10µs/div)
6
3237.2006.01.1.4
AAT3237
300mA MicroPower™ LDO with PowerOK
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA = 25°C.
Over-Current Protection
AAT3237 Self Noise
1200
1000
800
600
400
200
0
10
1
0.1
0.01
-200
0.01
0.1
1
10
100
1000
Time (20ms/div)
Frequency (kHz)
VEN(H) and VEN(L) vs. VIN
1.250
1.225
1.200
1.175
VEN(H)
1.150
1.125
1.100
VEN(L)
1.075
1.050
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VIN (V)
3237.2006.01.1.4
7
AAT3237
300mA MicroPower™ LDO with PowerOK
Functional Block Diagram
IN
OUT
Over-Current
Protection
Over-Temperature
Protection
Error
Amplifier
EN
POK
Voltage
Reference
94%
GND
The device enable circuit is provided to shut down
the LDO regulator for power conservation in portable
products. The enable circuit has an additional out-
put capacitor discharge circuit to assure sharp appli-
cation circuit turn-off upon device shutdown.
Functional Description
The AAT3237 is intended for LDO regulator appli-
cations where output current load requirements
range from no load to 300mA.
This LDO regulator has complete short-circuit and
thermal protection. The integral combination of
these two internal protection circuits gives the
AAT3237 a comprehensive safety system during
extreme adverse operating conditions. Device
power dissipation is limited to the package type
and thermal dissipation properties. Refer to the
Thermal Considerations section of this datasheet
for details on device operation at maximum output
current loads.
The advanced circuit design of the AAT3237 pro-
vides excellent transient response and fast turn-on
ability. The LDO regulator output has been specif-
ically optimized to function with low-cost, low-ESR
ceramic capacitors. However, the design will allow
for operation over a wide range of capacitor types.
The AAT3237 has an integrated Power-OK com-
parator which indicates when the output is out of
regulation.
8
3237.2006.01.1.4
AAT3237
300mA MicroPower™ LDO with PowerOK
Capacitor Characteristics
Ceramic composition capacitors are highly recom-
Applications Information
To assure the maximum possible performance is
obtained from the AAT3237, please refer to the fol-
lowing application recommendations.
mended over all other types of capacitors for use
with the AAT3237. Ceramic capacitors offer many
advantages over their tantalum and aluminum elec-
trolytic counterparts. A ceramic capacitor typically
has very low ESR, is lower cost, has a smaller PCB
footprint, and is non-polarized. Line and load tran-
sient response of the LDO regulator is improved by
using low ESR ceramic capacitors. Since ceramic
capacitors are non-polarized, they are not prone to
incorrect connection damage.
Input Capacitor
Typically, a 1µF or larger capacitor is recommend-
ed for CIN in most applications. A CIN capacitor is
not required for basic LDO regulator operation.
However, if the AAT3237 is physically located more
than three centimeters from an input power source,
a CIN capacitor will be needed for stable operation.
CIN should be located as closely to the device VIN
pin as practically possible. CIN values greater than
1µF will offer superior input line transient response
and will assist in maximizing the highest possible
power supply ripple rejection.
Equivalent Series Resistance: ESR is a very
important characteristic to consider when selecting a
capacitor. ESR is the internal series resistance asso-
ciated with a capacitor that includes lead resistance,
internal connections, size and area, material compo-
sition, and ambient temperature. Typically, capacitor
ESR is measured in milliohms for ceramic capacitors
and can range to more than several ohms for tanta-
lum or aluminum electrolytic capacitors.
Ceramic, tantalum, or aluminum electrolytic capac-
itors may be selected for CIN. There is no specific
capacitor ESR requirement for CIN. However, for
300mA LDO regulator output operation, ceramic
capacitors are recommended for CIN due to their
inherent capability over tantalum capacitors to with-
stand input current surges from low impedance
sources such as batteries in portable devices.
Ceramic Capacitor Materials: Ceramic capaci-
tors less than 0.1µF are typically made from NPO
or C0G materials. NPO and C0G materials gener-
ally have tight tolerance and are very stable over
temperature. Larger capacitor values are usually
composed of X7R, X5R, Z5U, or Y5V dielectric
materials. These two material types are not recom-
mended for use with LDO regulators since the
capacitor tolerance can vary more than ±50% over
the operating temperature range of the device. A
2.2µF Y5V capacitor could be reduced to 1µF over
temperature; this could cause problems for circuit
operation. X7R and X5R dielectrics are much more
desirable. The temperature tolerance of X7R
dielectric is better than ±15%.
Output Capacitor
For proper load voltage regulation and operational
stability, a capacitor is required between pins VOUT
and GND. The COUT capacitor connection to
the LDO regulator ground pin should be made as
direct as practically possible for maximum device
performance.
The AAT3237 has been specifically designed to func-
tion with very low ESR ceramic capacitors. For best
performance, ceramic capacitors are recommended.
Capacitor area is another contributor to ESR.
Capacitors that are physically large in size will have
a lower ESR when compared to a smaller sized
capacitor of an equivalent material and capacitance
value. These larger devices can improve circuit tran-
sient response when compared to an equal value
capacitor in a smaller package size.
Typical output capacitor values for maximum output
current conditions range from 1µF to 10µF.
Applications utilizing the exceptionally low output
noise and optimum power supply ripple rejection
characteristics of the AAT3237 should use 2.2µF or
greater for COUT. If desired, COUT may be increased
without limit.
Consult capacitor vendor datasheets carefully
when selecting capacitors for LDO regulators.
In low output current applications where output
load is less than 10mA, the minimum value for
COUT can be as low as 0.47µF.
3237.2006.01.1.4
9
AAT3237
300mA MicroPower™ LDO with PowerOK
pass device to prevent the possibility of over-temper-
ature damage. The LDO regulator output will remain
in a shutdown state until the internal die temperature
falls back below the 145°C trip point.
POK Output
The AAT3237 features an integrated Power-OK
comparator which can be used as an error flag. The
POK open-drain output goes low when OUT is 6%
below its nominal regulation voltage. Connect a
pull-up resistor from POK to OUT.
The combination and interaction between the short-
circuit and thermal protection systems allows the
LDO regulator to withstand indefinite short-circuit
conditions without sustaining permanent damage.
Enable Function
The AAT3237 features an LDO regulator enable/
disable function. This pin (EN) is active high and is
compatible with CMOS logic. To assure the LDO
regulator will switch on, the EN turn-on control level
must be greater than 2.0V. The LDO regulator will
go into the disable shutdown mode when the volt-
age on the EN pin falls below 0.6V. If the enable
function is not needed in a specific application, it
may be tied to VIN to keep the LDO regulator in a
continuously on state.
No-Load Stability
The AAT3237 is designed to maintain output volt-
age regulation and stability under operational no-
load conditions. This is an important characteristic
for applications where the output current may drop
to zero.
Reverse Output-to-Input Voltage
Conditions and Protection
When the LDO regulator is in shutdown mode, an
internal 1.5kΩ resistor is connected between VOUT
and GND. This is intended to discharge COUT when
the LDO regulator is disabled. The internal 1.5kΩ
has no adverse effect on device turn-on time.
Under normal operating conditions, a parasitic
diode exists between the output and input of the
LDO regulator. The input voltage should always
remain greater than the output load voltage, main-
taining a reverse bias on the internal parasitic
diode. Conditions where VOUT might exceed VIN
should be avoided since this would forward bias
the internal parasitic diode and allow excessive
current flow into the VOUT pin, possibly damaging
the LDO regulator.
Short-Circuit Protection
The AAT3237 contains an internal short-circuit pro-
tection circuit that will trigger when the output load
current exceeds the internal threshold limit. Under
short-circuit conditions, the output of the LDO reg-
ulator will be current limited until the short-circuit
condition is removed from the output or LDO regu-
lator package power dissipation exceeds the
device thermal limit.
In applications where there is a possibility of VOUT
exceeding VIN for brief amounts of time during nor-
mal operation, the use of a larger value CIN capaci-
tor is highly recommended. A larger value of CIN
with respect to COUT will effect a slower CIN decay
rate during shutdown, thus preventing VOUT from
exceeding VIN. In applications where there is a
greater danger of VOUT exceeding VIN for extended
periods of time, it is recommended to place a
Schottky diode across VIN to VOUT (connecting the
cathode to VIN and anode to VOUT). The Schottky
diode forward voltage should be less than 0.45V.
Thermal Protection
The AAT3237 has an internal thermal protection cir-
cuit which will turn on when the device die tempera-
ture exceeds 145°C. The internal thermal protection
circuit will actively turn off the LDO regulator output
10
3237.2006.01.1.4
AAT3237
300mA MicroPower™ LDO with PowerOK
Ordering Information
Output Voltage
Package
Marking1
Part Number (Tape and Reel)2
1.2V
1.5V
1.8V
2.0V
2.3V
2.5V
2.7V
2.8V
2.85V
2.9V
3.0V
3.3V
3.5V
1.2V
1.5V
1.8V
2.0V
2.3V
2.5V
2.7V
2.8V
2.85V
2.9V
3.0V
3.3V
3.5V
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
AAT3237IGU-1.2-T1
AAT3237IGU-1.5-T1
AAT3237IGU-1.8-T1
AAT3237IGU-2.0-T1
AAT3237IGU-2.3-T1
AAT3237IGU-2.5-T1
AAT3237IGU-2.7-T1
AAT3237IGU-2.8-T1
AAT3237IGU-2.85-T1
AAT3237IGU-2.9-T1
AAT3237IGU-3.0-T1
AAT3237IGU-3.3-T1
AAT3237IGU-3.5-T1
AAT3237IJS-1.2-T1
AAT3237IJS-1.5-T1
AAT3237IJS-1.8-T1
AAT3237IJS-2.0-T1
AAT3237IJS-2.3-T1
AAT3237IJS-2.5-T1
AAT3237IJS-2.7-T1
AAT3237IJS-2.8-T1
AAT3237IJS-2.85-T1
AAT3237IJS-2.9-T1
AAT3237IJS-3.0-T1
AAT3237IJS-3.3-T1
AAT3237IJS-3.5-T1
FBXYY
GRXYY
GSXYY
GMXYY
HRXYY
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
1. XYY = assembly and date code.
2. Sample stock is generally held on all part numbers listed in BOLD.
3237.2006.01.1.4
11
AAT3237
300mA MicroPower™ LDO with PowerOK
Package Information
SOT23-6
2.85 0.15
1.90 BSC
0.95 BSC
0.15 0.07
GAUGE PLANE
10° 5°
0.60 REF
0.40 0.10 × 6
0.45 0.15
0.10 BSC
All dimensions in millimeters.
12
3237.2006.01.1.4
AAT3237
300mA MicroPower™ LDO with PowerOK
SC70JW-8
0.50 BSC 0.50 BSC 0.50 BSC
0.225 0.075
2.00 0.20
0.048REF
0.100
0.45 0.10
4° 4°
7° 3°
2.10 0.30
All dimensions in millimeters.
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3237.2006.01.1.4
13
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