AAT3221IJS-3.2-T1 [AAT]
150mA NanoPower⑩ LDO Linear Regulator; 150毫安纳安级™ LDO线性稳压器
| 型号： | AAT3221IJS-3.2-T1 |
| 厂家： | 
ADVANCED ANALOG TECHNOLOGY, INC. |
| 描述： | 150mA NanoPower⑩ LDO Linear Regulator |
| 文件： | 总18页 (文件大小：190K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
™
PowerLinear
General Description
Features
The AAT3221 and AAT3222 PowerLinear
NanoPower low dropout (LDO) linear regulators
are ideal for portable applications where extended
battery life is critical. These devices feature
extremely low quiescent current, typically 1.1µA.
Dropout voltage is also very low, typically less than
200mV at the maximum output current of 150mA.
The AAT3221/2 have an enable pin feature which,
when asserted, will enter the LDO regulator into
shutdown mode, removing power from its load and
offering extended power conservation capabilities
for portable battery-powered applications.
•
•
•
•
•
•
•
•
•
1.1µA Quiescent Current
Low Dropout: 200mV (typical)
Guaranteed 150mA Output
High Accuracy: ±2%
Current Limit Protection
Over-Temperature Protection
Extremely Low Power Shutdown Mode
Low Temperature Coefficient
Factory-Programmed Output Voltages
— 1.6V to 3.5V
•
Stable Operation With Virtually Any Output
Capacitor Type
•
•
•
•
Active High or Low Enable Pin
4kV ESD
5-Pin SOT23 or 8-Pin SC70JW Package
-40°C to +85°C Temperature Range
The AAT3221/2 have output short-circuit and over-
current protection. In addition, the devices also
have an over-temperature protection circuit, which
will shut down the LDO regulator during extended
over-current events. The devices are available
with active high or active low enable input.
The AAT3221 and AAT3222 are available in Pb-free,
space-saving 5-pin SOT23 packages. The AAT3221
is also available in a Pb-free, 8-pin SC70JW pack-
age. The device is rated over the -40°C to +85°C
temperature range. Since only a small, 1µF ceram-
ic output capacitor is recommended, often the only
space used is that occupied by the AAT3221/2 itself.
The AAT3221/2 provide a compact and cost-effec-
tive voltage conversion solution.
Applications
•
•
•
•
•
•
•
Cellular Phones
Digital Cameras
Handheld Electronics
Notebook Computers
PDAs
Portable Communication Devices
Remote Controls
The AAT3221 and AAT3122 are similar to the
AAT3220, with the exception that they offer further
power savings with an enable pin.
Typical Application
INPUT
OUTPUT
ENABLE
(ENABLE)
(EN)
CIN
1µF
COUT
1µF
GND
GND
3221.2005.12.1.11
1
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Pin Descriptions
Pin #
AAT3221
AAT3222
Symbol
IN
Function
SOT23-5
SC70JW-8
1
2
3
2
5, 6, 7, 8
4
2
1
5
Input pin.
GND
Ground connection pin.
EN (EN)
Enable input. Logic compatible enable with
active high or active low option available; see
Ordering Information and Applications
Information for details.
4
5
3
1
4
3
NC
Not connected.
OUT
Output pin; should be decoupled with 1µF or
greater capacitor.
Pin Configuration
AAT3221
SOT23-5
(Top View)
AAT3221
SC70JW-8
(Top View)
AAT3222
SOT23-5
(Top View)
5
4
5
4
1
1
OUT
NC
EN (EN)
NC
IN
GND
GND
IN
8
7
6
5
1
2
3
4
GND
GND
GND
GND
OUT
IN
NC
2
3
2
3
(EN) EN
(EN) EN
OUT
2
3221.2005.12.1.11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Absolute Maximum Ratings1
TA = 25°C, unless otherwise noted.
Symbol
Description
Value
Units
VIN
VEN
Input Voltage, <30ms, 10% DC (continuous max = 6.0V)
EN (EN) to GND Voltage
-0.3 to 7
-0.3 to 6
0.3
V
V
VENIN(MAX)
IOUT
Maximum EN (EN) to Input Voltage
Maximum DC Output Current
V
PD/(VIN-VO)
-40 to 150
mA
°C
TJ
Operating Junction Temperature Range
Thermal Information2
Symbol
Description
Value
Units
ΘJA
PD
Thermal Resistance
Power Dissipation
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.
3221.2005.12.1.11
3
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Electrical Characteristics
VIN = VOUT(NOM) + 1V, IOUT = 1mA, COUT = 1µF, TA = 25°C, unless otherwise noted.
Symbol Description
Conditions
Min
Typ Max Units
VOUT
IOUT
ISC
IQ
ISD
DC Output Voltage Tolerance
Output Current
Short-Circuit Current
Ground Current
Shutdown Current
-2.0
150
2.0
%
VOUT > 1.2V
VOUT < 0.4V
VIN = 5V, No Load
EN = Inactive
mA
mA
µA
nA
350
1.1
20
2.5
0.4
∆VOUT
VOUT*∆VIN
/
Line Regulation
VIN = 4.0V to 5.5V
0.15
%/V
VOUT = 1.6
VOUT = 1.7
VOUT = 1.8
VOUT = 1.9
VOUT = 2.0
VOUT = 2.3
VOUT = 2.4
VOUT = 2.5
1.2
1.1
1.0
1.0
0.9
0.8
0.8
0.8
0.8
0.7
0.7
0.7
0.7
0.6
0.6
0.5
0.5
230
220
210
205
200
190
190
190
190
188
180
180
1.69
1.67
1.65
1.62
1.58
1.45
1.40
1.35
1.30
1.25
1.20
1.20
1.18
1.15
1.06
1.00
1.00
275
265
255
247
240
235
230
228
225
222
220
220
∆VOUT/VOUT Load Regulation
IL = 1 to 100mA VOUT = 2.6
VOUT = 2.7
%
VOUT = 2.8
VOUT = 2.85
VOUT = 2.9
VOUT = 3.0
VOUT = 3.1
VOUT = 3.3
VOUT = 3.5
VOUT = 2.3
VOUT = 2.4
VOUT = 2.5
VOUT = 2.6
VOUT = 2.7
VOUT = 2.8
VDO
Dropout Voltage1, 2
IOUT = 100mA
mV
VOUT = 2.85
VOUT = 2.9
VOUT = 3.0
VOUT = 3.1
VOUT = 3.3
V
OUT = 3.5
1. VDO is defined as VIN - VOUT when VOUT is 98% of nominal.
2. For VOUT < 2.3V, VDO = 2.5V - VOUT
.
4
3221.2005.12.1.11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Electrical Characteristics
VIN = VOUT(NOM) + 1V, IOUT = 1mA, COUT = 1µF, TA = 25°C, unless otherwise noted.
Symbol Description
Conditions
Min
Typ Max Units
VEN(L)
EN Input Low Voltage
0.8
V
V
IN = 2.7V to 3.6V
2.0
2.4
VEN(H)
EN Input High Voltage
V
VIN = 5V
VON = 5.5V
100Hz
IEN(SINK)
PSRR
TSD
THYS
eN
EN Input Leakage
0.01
50
140
20
350
80
1
µA
dB
°C
Power Supply Rejection Ratio
Over-Temperature Shutdown Threshold
Over-Temperature Shutdown Hysteresis
Output Noise
°C
µVRMS
PPM/°C
TC
Output Voltage Temperature Coefficient
3221.2005.12.1.11
5
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Typical Characteristics
Unless otherwise noted, VIN = VOUT + 1V, TA = 25°C, COUT = 5.6µF Ceramic, IOUT = 100mA.
Output Voltage vs. Output Current Output Voltage vs. Input Voltage
3.03
3.02
3.01
3
3.1
3
1mA
2.9
2.8
2.7
2.6
2.5
-30°C
40mA
25°C
2.99
2.98
2.97
80°C
10mA
2.7
2.9
3.1
3.3
3.5
0
20
40
60
80
100
Input Voltage (V)
Output Current (mA)
Output Voltage vs. Input Voltage
Dropout Voltage vs. Output Current
3.03
3.02
3.01
3
400
300
200
100
0
1mA
80°C
10mA
25°C
40mA
-30°C
2.99
3.5
4
4.5
5
5.5
0
25
50
75
100
125
150
Input Voltage (V)
Output Current (mA)
Supply Current vs. Input Voltage
PSRR with 10mA Load
2.0
60
40
20
0
1.6
25°C
80°C
1.2
0.8
0.4
0
-30°C
0
1
2
3
4
5
6
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
Input Voltage (V)
Frequency (Hz)
6
3221.2005.12.1.11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Typical Characteristics
Unless otherwise noted, VIN = VOUT + 1V, TA = 25°C, COUT = 5.6µF Ceramic, IOUT = 100mA.
Noise Spectrum
Line Response with 1mA Load
30
20
10
0
3.8
3.6
3.4
3.2
3
6
5
4
3
2
1
0
Input
-10
-20
-30
Output
2.8
2.6
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
-200
0
200
400
600
800
Frequency (Hz)
Time (µs)
Line Response with 10mA Load
Line Response with 100mA Load
3.8
3.6
3.4
3.2
3
6
5
4
3
2
1
3.8
3.6
3.4
3.2
3
6
5
4
3
2
1
0
Input
Input
Output
Output
2.8
2.6
2.8
2.6
0
-200
0
200
400
600
800
-200
0
200
400
600
800
Time (µs)
Time (µs)
Load Transient - 1mA / 40mA
Load Transient - 1mA / 80mA
4
3
2
320
240
160
80
4
3
2
320
240
160
80
Output
Output
0
3
0
-1
0
1
2
-1
0
1
2
3
Time (ms)
Time (ms)
3221.2005.12.1.11
7
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Typical Characteristics
Unless otherwise noted, VIN = VOUT + 1V, TA = 25°C, COUT = 5.6µF Ceramic, IOUT = 100mA.
Power-Up with 1mA Load Turn-On with 1mA Load
4
3
2
1
0
5
4
4
3
2
1
0
3
3
2
2
Enable
Enable
1
1
0
-1
-2
-3
0
Output
Output
-1
-1
-1
-1
0
1
2
2
2
-1
0
1
2
Time (ms)
Time (ms)
Turn-On with 10mA Load
Power-Up with 10mA Load
4
3
2
1
0
5
4
4
3
2
1
0
3
2
3
2
Enable
Enable
1
1
0
-1
-2
-3
0
Output
Output
-1
0
1
-1
0
1
2
Time (ms)
Time (ms)
Power-Up with 100mA Load
Turn-On with 100mA Load
4
3
2
5
4
4
3
2
3
3
2
2
Enable
1
1
Enable
Output
0
1
-1
-2
-3
1
0
Output
0
0
-1
0
1
-1
0
1
2
Time (ms)
Time (ms)
8
3221.2005.12.1.11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Functional Block Diagram
IN
OUT
Over-Current
Protection
Over-Temperature
Protection
EN
VREF
GND
high performance LDO regulator is especially well
suited for circuit applications that are sensitive to
load circuit power consumption and extended bat-
Functional Description
The AAT3221 and AAT3222 are intended for LDO
regulator applications where output current load
requirements range from no load to 150mA. The
advanced circuit design of the AAT3221/2 has been
optimized for very low quiescent or ground current
consumption, making it ideal for use in power man-
agement systems for small battery-operated
devices. The typical quiescent current level is just
1.1µA. AAT3221/2 devices also contain an enable
circuit which has been provided to shut down the
LDO regulator for additional power conservation in
portable products. In the shutdown state, the LDO
draws less than 1µA from input supply.
tery life.
The LDO regulator output has been specifically
optimized to function with low-cost, low-ESR
ceramic capacitors. However, the design will allow
for operation with a wide range of capacitor types.
The AAT3221/2 has complete short-circuit and
thermal protection. The integral combination of
these two internal protection circuits gives the
AAT3221/2 a comprehensive safety system to
guard against extreme adverse operating condi-
tions. Device power dissipation is limited to the
package type and thermal dissipation properties.
Refer to the Thermal Considerations section of this
document for details on device operation at maxi-
mum output load levels.
The LDO also demonstrates excellent power sup-
ply ripple rejection (PSRR) and load and line tran-
sient response characteristics. The AAT3221/2
3221.2005.12.1.11
9
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
The total output capacitance required can be cal-
culated using the following formula:
Applications Information
To ensure that the maximum possible performance
is obtained from the AAT3221/2, please refer to the
following application recommendations.
∆I
∆V
COUT
=
× 15µF
Where:
Input Capacitor
∆I = maximum step in output current
A 1µF or larger capacitor is typically recommended
for CIN in most applications. A CIN capacitor is not
required for basic LDO regulator operation.
However, if the AAT3221/2 is physically located any
distance more than one or two centimeters from the
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 power supply ripple rejection.
∆V = maximum excursion in voltage that the load
can tolerate
Note that use of this equation results in capacitor
values approximately two to four times the typical
value needed for an AAT3221/2 at room tempera-
ture. The increased capacitor value is recommend-
ed if tight output tolerances must be maintained over
extreme operating conditions and maximum opera-
tional temperature excursions. If tantalum or alu-
minum electrolytic capacitors are used, the capacitor
value should be increased to compensate for the
substantial ESR inherent to these capacitor types.
Ceramic, tantalum, or aluminum electrolytic capac-
itors may be selected for CIN, as there is no specif-
ic capacitor ESR requirement. For 150mA LDO
regulator output operation, ceramic capacitors are
recommended for CIN due to their inherent capabil-
ity over tantalum capacitors to withstand input cur-
rent surges from low impedance sources such as
batteries in portable devices.
Capacitor Characteristics
Ceramic composition capacitors are highly recom-
mended over all other types of capacitors for use
with the AAT3221/2. Ceramic capacitors offer
many advantages over their tantalum and alu-
minum electrolytic counterparts. A ceramic capac-
itor typically has very low ESR, is lower cost, has a
smaller PCB footprint, and is non-polarized. Line
and load transient response of the LDO regulator is
improved by using low-ESR ceramic capacitors.
Since ceramic capacitors are non-polarized, they
are less prone to damage if incorrectly connected.
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 per-
formance. The AAT3221/2 has been specifically
designed to function with very low ESR ceramic
capacitors. Although the device is intended to oper-
ate with these low ESR capacitors, it is stable over
a wide range of capacitor ESR, thus it will also work
with some higher ESR tantalum or aluminum elec-
trolytic capacitors. However, for best performance,
ceramic capacitors are recommended.
Equivalent Series Resistance (ESR): ESR is a
very important characteristic to consider when
selecting a capacitor. ESR is the internal series
resistance associated with a capacitor, which
includes lead resistance, internal connections,
capacitor size and area, material composition, and
ambient temperature. Typically, capacitor ESR is
measured in milliohms for ceramic capacitors and
can range to more than several ohms for tantalum
or aluminum electrolytic capacitors.
The value of COUT typically ranges from 0.47µF to
10µF; however, 1µF is sufficient for most operating
conditions.
Ceramic Capacitor Materials: Ceramic capacitors
less than 0.1µF are typically made from NPO or C0G
materials. NPO and C0G materials are typically tight
tolerance and very stable over temperature. Larger
capacitor values are typically composed of X7R,
X5R, Z5U, and Y5V dielectric materials. Large
If large output current steps are required by an
application, then an increased value for COUT
should be considered. The amount of capacitance
needed can be calculated from the step size of the
change in output load current expected and the
voltage excursion that the load can tolerate.
10
3221.2005.12.1.11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
ceramic capacitors, typically greater than 2.2µF, are
will rapidly increase. Once the regulator's power
dissipation capacity has been exceeded and the
internal die temperature reaches approximately
140°C, the system thermal protection circuit will
become active. The internal thermal protection cir-
cuit will actively turn off the LDO regulator output
pass device to prevent the possibility of over-tem-
perature damage. The LDO regulator output will
remain in a shutdown state until the internal die
temperature falls back below the 140°C trip point.
often available in low-cost Y5V and Z5U dielectrics.
These two material types are not recommended for
use with LDO regulators since the capacitor tolerance
can vary more than ±50% over the operating temper-
ature range of the device. A 2.2µF Y5V capacitor
could be reduced to 1µF over the full operating tem-
perature range. This can cause problems for circuit
operation and stability. X7R and X5R dielectrics are
much more desirable. The temperature tolerance of
X7R dielectric is better than ±15%.
The interaction between the short-circuit and ther-
mal protection systems allows the LDO regulator to
withstand indefinite short-circuit conditions without
sustaining permanent damage.
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 equivalent material and capacitance
value. These larger devices can also improve cir-
cuit transient response when compared to an equal
value capacitor in a smaller package size.
No-Load Stability
The AAT3221/2 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. An output capacitor is required for stability
under no-load operating conditions. Refer to the
output capacitor considerations section of this doc-
ument for recommended typical output capacitor
values.
Consult capacitor vendor datasheets carefully when
selecting capacitors for use with LDO regulators.
Enable Function
The AAT3221/2 features an LDO regulator enable /
disable function. This pin (EN) is compatible with
CMOS logic. Active high or active low options are
available (see Ordering Information). For a logic
high signal, the EN control level must be greater
than 2.4 volts. A logic low signal is asserted when
the voltage on the EN pin falls below 0.6 volts. For
example, the active high version AAT3221/2 will
turn on when a logic high is applied to the EN pin.
If the enable function is not needed in a specific
application, it may be tied to the respective voltage
level to keep the LDO regulator in a continuously
on state; e.g., the active high version AAT3221/2
will tie VIN to EN to remain on.
Thermal Considerations and High
Output Current Applications
The AAT3221/2 is designed to deliver a continuous
output load current of 150mA under normal operat-
ing conditions. The limiting characteristic for the
maximum output load safe operating area is essen-
tially package power dissipation and the internal pre-
set thermal limit of the device. In order to obtain high
operating currents, careful device layout and circuit
operating conditions need to be taken into account.
The following discussions will assume the LDO reg-
ulator is mounted on a printed circuit board utilizing
the minimum recommended footprint and the print-
ed circuit board is 0.062-inch thick FR4 material with
one ounce copper.
Short-Circuit Protection and Thermal
Protection
The AAT3221/2 is protected by both current limit
and over-temperature protection circuitry. The
internal short-circuit current limit is designed to acti-
vate when the output load demand exceeds the
maximum rated output. If a short-circuit condition
were to continually draw more than the current limit
threshold, the LDO regulator's output voltage will
drop to a level necessary to supply the current
demanded by the load. Under short-circuit or other
over-current operating conditions, the output volt-
age will drop and the AAT3221/2 die temperature
At any given ambient temperature (TA), the maxi-
mum package power dissipation can be deter-
mined by the following equation:
PD(MAX) = [TJ(MAX) - TA] / ΘJA
Constants for the AAT3221/2 are TJ(MAX), the maxi-
mum junction temperature for the device which is
125°C and ΘJA = 150°C/W, the package thermal
resistance. Typically, maximum conditions are cal-
3221.2005.12.1.11
11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
culated at the maximum operating temperature
input operating voltage for the AAT3221/2, thus at
25°C the device would not have any thermal con-
cerns or operational VIN(MAX) limits.
where TA = 85°C, under normal ambient conditions
TA = 25°C. Given TA = 85°C, the maximum pack-
age power dissipation is 267mW. At TA = 25°C, the
maximum package power dissipation is 667mW.
This situation can be different at 85°C. The follow-
ing is an example for an AAT3221/2 set for a 2.5 volt
output at 85°C:
The maximum continuous output current for the
AAT3221/2 is a function of the package power dis-
sipation and the input-to-output voltage drop
across the LDO regulator. Refer to the following
simple equation:
VOUT = 2.5 volts
IOUT = 150mA
IGND = 1.1µA
VIN(MAX)=(267mW+(2.5Vx150mA))/(150mA +1.1µA)
IOUT(MAX) < PD(MAX) / (VIN - VOUT
)
V
IN(MAX) = 4.28V
For example, if VIN = 5V, VOUT = 2.5V and TA = 25°C,
IOUT(MAX) < 267mA. The output short-circuit protec-
tion threshold is set between 150mA and 300mA. If
the output load current were to exceed 267mA or if
the ambient temperature were to increase, the inter-
nal die temperature would increase. If the condition
remained constant and the short-circuit protection
did not activate, there would be a potential damage
hazard to the LDO regulator since the thermal pro-
tection circuit would only activate after a short-circuit
event occured on the LDO regulator output.
From the discussion above, PD(MAX) was deter-
mined to equal 267mW at TA = 85°C.
Higher input-to-output voltage differentials can be
obtained with the AAT3221/2, while maintaining
device functions in the thermal safe operating area.
To accomplish this, the device thermal resistance
must be reduced by increasing the heat sink area
or by operating the LDO regulator in a duty-cycled
mode.
For example, an application requires VIN = 5.0V
while VOUT = 2.5V at a 150mA load and TA = 85°C.
VIN is greater than 4.28V, which is the maximum
safe continuous input level for VOUT = 2.5V at
150mA for TA = 85°C. To maintain this high input
voltage and output current level, the LDO regulator
must be operated in a duty-cycled mode. Refer to
the following calculation for duty-cycle operation:
To determine the maximum input voltage for a
given load current, refer to the following equation.
This calculation accounts for the total power dissi-
pation of the LDO regulator, including that caused
by ground current.
PD(MAX) = (VIN - VOUT)IOUT + (VIN x IGND
)
This formula can be solved for VIN to determine the
maximum input voltage.
IGND = 1.1µA
IOUT = 150mA
VIN = 5.0 volts
VOUT = 2.5 volts
VIN(MAX) = (PD(MAX) + (VOUT x IOUT)) / (IOUT + IGND
)
The following is an example for an AAT3221/2 set
for a 2.5 volt output:
%DC = 100(PD(MAX) / ((VIN - VOUT)IOUT + (VIN x IGND))
%DC=100(267mW/((5.0V-2.5V)150mA+(5.0Vx1.1µA))
%DC = 71.2%
V
OUT = 2.5 volts
IOUT = 150mA
IGND = 1.1µA
PD(MAX) is assumed to be 267mW.
VIN(MAX)=(667mW+(2.5Vx150mA))/(150mA +1.1µA)
VIN(MAX) = 6.95V
For a 150mA output current and a 2.5 volt drop
across the AAT3221/2 at an ambient temperature
of 85°C, the maximum on-time duty cycle for the
device would be 71.2%.
From the discussion above, PD(MAX) was deter-
mined to equal 667mW at TA = 25°C. Thus, the
AAT3221/2 can sustain a constant 2.5V output at a
150mA load current as long as VIN is ≤6.95V at an
ambient temperature of 25°C. 5.5V is the maximum
The following family of curves shows the safe oper-
ating area for duty-cycled operation from ambient
room temperature to the maximum operating level.
12
3221.2005.12.1.11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
High Peak Output Current Applications
Device Duty Cycle vs. VDROP
Some applications require the LDO regulator to
operate at continuous nominal levels with short
duration, high-current peaks. The duty cycles for
both output current levels must be taken into
account. To do so, one would first need to calcu-
late the power dissipation at the nominal continu-
ous level, then factor in the addition power dissipa-
tion due to the short duration, high-current peaks.
(VOUT = 2.5V @ 25°C)
3.5
3
200mA
2.5
2
1.5
1
0.5
0
For example, a 2.5V system using an AAT3221/
2IGV-2.5-T1 operates at a continuous 100mA load
current level and has short 150mA current peaks.
The current peak occurs for 378µs out of a 4.61ms
period. It will be assumed the input voltage is 5.0V.
0
10
20
30
40
50
60
70
80
90
100
Duty Cycle (%)
First, the current duty cycle percentage must be
calculated:
% Peak Duty Cycle: X/100 = 378ms/4.61ms
% Peak Duty Cycle = 8.2%
Device Duty Cycle vs. VDROP
(VOUT = 2.5V @ 50°C)
The LDO regulator will be under the 100mA load
for 91.8% of the 4.61ms period and have 150mA
peaks occurring for 8.2% of the time. Next, the
continuous nominal power dissipation for the
100mA load should be determined then multiplied
by the duty cycle to conclude the actual power dis-
sipation over time.
3.5
3
200mA
2.5
2
150mA
1.5
1
0.5
0
PD(MAX) = (VIN - VOUT)IOUT + (VIN x IGND
)
0
10
20
30
40
50
60
70
80
90
100
PD(100mA) = (5.0V - 2.5V)100mA + (5.0V x 1.1mA)
PD(100mA) = 250mW
Duty Cycle (%)
PD(91.8%D/C) = %DC x PD(100mA)
PD(91.8%D/C) = 0.918 x 250mW
PD(91.8%D/C) = 229.5mW
Device Duty Cycle vs. VDROP
(VOUT = 2.5V @ 85°C)
3.5
3
100mA
2.5
2
200mA
150mA
1.5
1
0.5
0
0
10
20
30
40
50
60
70
80
90
100
Duty Cycle (%)
3221.2005.12.1.11
13
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
The power dissipation for a 100mA load occurring
Printed Circuit Board Layout
Recommendations
for 91.8% of the duty cycle will be 229.5mW. Now
the power dissipation for the remaining 8.2% of the
duty cycle at the 150mA load can be calculated:
In order to obtain the maximum performance from
the AAT3221/2 LDO regulator, very careful attention
must be considered in regard to the printed circuit
board layout. If grounding connections are not prop-
erly made, power supply ripple rejection and LDO
regulator transient response can be compromised.
PD(MAX) = (VIN - VOUT)IOUT + (VIN x IGND
)
PD(150mA) = (5.0V - 2.5V)150mA + (5.0V x 1.1mA)
PD(150mA) = 375mW
PD(8.2%D/C) = %DC x PD(150mA)
PD(8.2%D/C) = 0.082 x 375mW
PD(8.2%D/C) = 30.75mW
The LDO regulator external capacitors CIN and
COUT should be connected as directly as possible
to the ground pin of the LDO regulator. For maxi-
mum performance with the AAT3221/2, the ground
pin connection should then be made directly back
to the ground or common of the source power sup-
ply. If a direct ground return path is not possible
due to printed circuit board layout limitations, the
LDO ground pin should then be connected to the
common ground plane in the application layout.
The power dissipation for a 150mA load occurring
for 8.2% of the duty cycle will be 20.9mW. Finally,
the two power dissipation levels can summed to
determine the total true power dissipation under the
varied load:
PD(total) = PD(100mA) + PD(150mA)
PD(total) = 229.5mW + 30.75mW
PD(total) = 260.25mW
The maximum power dissipation for the AAT3221/2
operating at an ambient temperature of 85°C is
267mW. The device in this example will have a total
power dissipation of 260.25mW. This is within the
thermal limits for safe operation of the device.
14
3221.2005.12.1.11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Ordering Information
Output Voltage
Enable
Package
Marking1
Part Number (Tape and Reel)2
1.6V
1.7V
1.8V
1.9V
2.0V
2.3V
2.4V
2.5V
2.6V
2.7V
2.8V
2.85V
2.9V
3.0V
3.1V
3.3V
3.5V
1.5V
1.6V
1.7V
1.8V
1.9V
2.0V
2.3V
2.4V
2.5V
2.6V
2.7V
2.8V
2.85V
2.9V
3.0V
3.1V
3.2V
3.3V
3.5V
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
SOT23-5
SOT23-5
GYXYY
GBXYY
BBXYY
CGXYY
BLXYY
FLXYY
FMXYY
AKXYY
GPXYY
GDXYY
AQXYY
BYXYY
JCXYY
ALXYY
GVXYY
AMXYY
BMXYY
AAT3221IGV-1.6-T1
AAT3221IGV-1.7-T1
AAT3221IGV-1.8-T1
AAT3221IGV-1.9-T1
AAT3221IGV-2.0-T1
AAT3221IGV-2.3-T1
AAT3221IGV-2.4-T1
AAT3221IGV-2.5-T1
AAT3221IGV-2.6-T1
AAT3221IGV-2.7-T1
AAT3221IGV-2.8-T1
AAT3221IGV-2.85-T1
AAT3221IGV-2.9-T1
AAT3221IGV-3.0-T1
AAT3221IGV-3.1-T1
AAT3221IGV-3.3-T1
AAT3221IGV-3.5-T1
AAT3221IJS-1.5-T1
AAT3221IJS-1.6-T1
AAT3221IJS-1.7-T1
AAT3221IJS-1.8-T1
AAT3221IJS-1.9-T1
AAT3221IJS-2.0-T1
AAT3221IJS-2.3-T1
AAT3221IJS-2.4-T1
AAT3221IJS-2.5-T1
AAT3221IJS-2.6-T1
AAT3221IJS-2.7-T1
AAT3221IJS-2.8-T1
AAT3221IJS-2.85-T1
AAT3221IJS-2.9-T1
AAT3221IJS-3.0-T1
AAT3221IJS-3.1-T1
AAT3221IJS-3.2-T1
AAT3221IJS-3.3-T1
AAT3221IJS-3.5-T1
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
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
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
SC70JW-8
BBXYY
CGXYY
BLXYY
FLXYY
FMXYY
AKXYY
GPXYY
GDXYY
AQXYY
BYXYY
JCXYY
ALXYY
GVXYY
LEXYY
AMXYY
BMXYY
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3221.2005.12.1.11
15
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Ordering Information
Output Voltage
Enable
Package
Marking1
Part Number (Tape and Reel)2
1.8V
2.0V
2.3V
2.4V
2.5V
2.7V
2.8V
2.85V
2.9V
3.0V
3.3V
3.5V
2.8V
3.3V
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active high
Active low
Active low
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
SOT23-5
BCXYY
AAT3222IGV-1.8-T1
AAT3222IGV-2.0-T1
AAT3222IGV-2.3-T1
AAT3222IGV-2.4-T1
AAT3222IGV-2.5-T1
AAT3222IGV-2.7-T1
AAT3222IGV-2.8-T1
AAT3222IGV-2.85-T1
AAT3222IGV-2.9-T1
AAT3222IGV-3.0-T1
AAT3222IGV-3.3-T1
AAT3222IGV-3.5-T1
AAT3221IGV-2.8-2 T1
AAT3221IGV-3.3-2-T1
ANXYY
AOXYY
BIXYY
FYXYY
BHXYY
APXYY
FTXYY
CXXYY
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 part numbers listed in BOLD.
16
3221.2005.12.1.11
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
Package Information
SOT23-5
2.85 0.15
1.90 BSC
0.95
BSC
0.60 REF
0.15 0.07
GAUGE PLANE
0.075 0.075
0.45 0.15
0.10 BSC
0.60 REF
10° 5°
0.40 0.10
All measurements in millimeters.
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 measurements in millimeters.
3221.2005.12.1.11
17
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
© Advanced Analogic Technologies, Inc.
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights,
or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice.
Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech
warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality con-
trol techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085
Phone (408) 737-4600
Fax (408) 737-4611
18
3221.2005.12.1.11
相关型号：
©2020 ICPDF网 联系我们和版权申明