AAT3221IJS-2.8-T1 - Skyworks Solutions, Inc.

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DATA SHEET

AAT3221/AAT3222: 150 mA NanopowerTM LDO Linear

Regulator

Applications

• Cellular phones

• Digital cameras

• Handheld electronics

• Notebook computers

• PDAs

• Portable communication devices

• Remote controls

Features

• Quiescent current: 1.1 µA

• Low dropout: 200 mV (typical)

• Guaranteed output: 150 mA

• High accuracy: ±2%

• Current limit protection

• Over-temperature protection

• Extremely low power shutdown mode

• Low temperature coefficient

• Factory-programmed output voltages: 1.5 V to 3.5 V

• Stable operation with virtually any output capacitor type

• Active high or low enable pin

• Small, 5-pin SOT23 or 8-pin SC70JW (AAT3221 only) package

(MSL1, 260 °C per JEDEC-J-STD-020)

Description

The AAT3221 and AAT3222 NanoPower™ Low Drop Out (LDO)

linear regulators are ideal for portable applications where

extended battery life is critical. These devices feature extremely

low quiescent current, typically 1.1 µA. Dropout voltage is also

very low, typically less than 200 mV at the maximum output

current of 150 mA. The AAT3221/3222 have an enable pin which,

when asserted, places the LDO regulator into shutdown mode,

removing power from its load and offering extended power

conservation capabilities for portable battery-powered

applications.

The AAT3221/3222 have output short-circuit and over-current

protection. In addition, the devices also have an over-temperature

protection circuit that shuts down the LDO regulator during

extended over-current events. Both 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 package. Since only a small, 1 µF

ceramic output capacitor is recommended, often the only space

used is that occupied by the AAT3221 or AAT3222. The

AAT3221/3222 provide a compact and cost-effective voltage

conversion solution.

Both devices are similar to the AAT3220, with the exception that

they offer further power savings with an enable pin.

A typical application circuit is shown in Figure 1. The pin

configuration is shown in Figures 2, 3, and 4. Signal pin

assignments and functional pin descriptions are provided in

Table 1.

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Figure 1. AAT3221/3222 Typical Application Circuit

Figure 2. AAT3221 Pinout

5-Pin SOT23-5 (Top View)

Figure 3. AAT3221 Pinout

8-Pin SC70JW-8 (Top View)

Figure 4. AAT3222 Pinout

5-Pin SOT23-5 (Top View)

Table 1. AAT3221/3222 Signal Descriptions

Pin #

Name Description

AAT3221 AAT3222

SOT23-5 SC70JW-8

1 2 2 IN Input pin.

2 5, 6, 7, 8 1 GND Ground connection pin.

3 4 5 EN(EN) Enable input. Logic compatible enable with active high or active low option

available; see Ordering Information and Applications Information for details.

4 3 4 NC Not connected.

5 1 3 OUT Output pin; should be decoupled with 1 µF or greater capacitor.

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Electrical and Mechanical Specifications

The absolute maximum ratings of the AAT3221/3222 are provided

in Table 2.

The recommended operating conditions are specified in Table 3,

and electrical specifications are provided in Table 4.

Typical performance characteristics of the AAT3221/3222 are

illustrated in Figures 5 through 22.

Table 2. AAT3221/3222 Absolute Maximum Ratings (Note 1)

Parameter Symbol Minimum Typical Maximum Units

Input Voltage, <30 ms, 10% DC (continuous max. = 6.0 V) VIN –0.3 +7 V

EN(EN) to GND Voltage VEN –0.3 +6 V

Maximum EN(EN) to Input Voltage VENIN(MAX) 0.3 V

Maximum DC Output Current IOUT PD/(VIN – VO) mA

Operating Junction Temperature Range TJ –40 +150 ºC

Thermal Resistance (Note 2) θJA SOT23-5 150 ºC/W

SC70JW-8 160 ºC/W

Power Dissipation (Note 2) PD SOT23-5 667 mW

SC70JW-8 625 mW

Electrostatic Discharge:

Human Body Model, Class 3A

ESD 4000 V

Note 1: Exposure to maximum rating conditions for extended periods may reduce device reliability. There is no damage to device with only one parameter set at the limit and all other

parameters set at or below their nominal value. Exceeding any of the limits listed may result in permanent damage to the device.

Note 2: Support IN high voltage pulse up to 7 V lasting 8 µs.

CAUTION: Although this device is designed to be as robust as possible, Electrostatic Discharge (ESD) can damage this device. This device

must be protected at all times from ESD. Static charges may easily produce potentials of several kilovolts on the human body

or equipment, which can discharge without detection. Industry-standard ESD precautions should be used at all times.

Table 3. AAT3221/3222 Recommended Operating Conditions

Parameter Symbol Minimum Typical Maximum Units

Input voltage (Note 1) VIN (VOUT + VDO) 5.5 V

Ambient temperature range TA –40 +85 °C

Note 1: To calculate minimum input voltage, use the following equation: VIN(MIN) = VOUT(MAX) + VDO(MAX) as long as VIN ≥ 2.5 V.

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Table 4. AAT3221/3222 Electrical Specifications (1 of 2) (Note 1)

(VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 1 µF, TA = 25 °C, Unless Otherwise Noted)

Parameter Symbol Test Condition Min Typical Max Units

DC output voltage tolerance VOUT –2.0 +2.0 %

Output current IOUT VOUT > 1.2 V 150 mA

Short-circuit current ISC VOUT < 0.4 V 350 mA

Ground current IQ VIN = 5 V, no load 1.1 2.5 µA

Shutdown current ISD EN = inactive 20 nA

Line regulation ∆Vout/Vout Х ∆Vin VIN = 4.0 V to 5.5 V 0.15 0.4 %/V

Load regulation ∆VOUT/VOUT IOUT = 1 to 100 mA

VOUT = 1.5 1.3 1.72

VOUT = 1.6 1.2 1.69

VOUT = 1.7 1.1 1.67

VOUT = 1.8 1.0 1.65

VOUT = 1.9 1.0 1.62

VOUT = 2.0 0.9 1.58

VOUT = 2.3 0.8 1.45

VOUT = 2.4 0.8 1.40

VOUT = 2.5 0.8 1.35

VOUT = 2.6 0.8 1.30

VOUT = 2.7 0.7 1.25

VOUT = 2.8 0.7 1.20

VOUT = 2.85 0.7 1.20

VOUT = 2.9 0.7 1.18

VOUT = 3.0 0.6 1.15

VOUT = 3.1 0.6 1.06

VOUT = 3.3 0.5 1.00

VOUT = 3.5 0.5 1.00

Dropout voltage (Note 2, 3) VDO IOUT = 100 mA

VOUT = 2.3 230 275

VOUT = 2.4 220 265

VOUT = 2.5 210 255

VOUT = 2.6 205 247

VOUT = 2.7 200 240

VOUT = 2.8 190 235

VOUT = 2.85 190 230

VOUT = 2.9 190 228

VOUT = 3.0 190 225

VOUT = 3.1 188 222

VOUT = 3.3 180 220

VOUT = 3.5 180 220

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Table 4. AAT3221/3222 Electrical Specifications (2 of 2) (Note 1)

(VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 1 µF, TA = 25 °C, Unless Otherwise Noted)

Parameter Symbol Test Condition Min Typical Max Units

EN Input low voltage VEN(L) 0.8 V

EN Input high voltage VEN(H) VIN = 2.7 V to 3.6 V 2.0 V

VIN = 5 V 2.4

EN Input leakage IEN(SINK) VON = 5.5 V 0.01 1 µA

Power supply rejection ratio PSRR @ 100 HZ 50 dB

Over-temperature shutdown threshold TSD 140 ºC

Over-temperature shutdown hysteresis THYS 20 ºC

Output noise eN f = 10 Hz to 10 kHz 350 µVRMS

Output voltage temperature coefficient TC 80 PPM/°C

Note 1: Performance is guaranteed only under the conditions listed in this Table.

Note 2: VDO is defined as VIN - VOUT when VOUT is 98% of nominal.

Note 3: For VOUT < 2.3 V, VDO = 2.5 V – VOUT.

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Typical Performance Characteristics

(VIN = VOUT + 1 V, TA = 25 °C, COUT = 5.6 µF Ceramic, IOUT = 1 mA, Unless Otherwise Noted)

Figure 5. Output Voltage vs Output Current

Figure 7. Output Voltage vs Input Voltage

Figure 9. Supply Current vs Input Voltage

Figure 6. Output Voltage vs Input Voltage

Figure 8. Dropout Voltage vs Output Current

Figure 10. PSRR with 10 mA Load

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Typical Performance Characteristics

(VIN = VOUT + 1 V, TA = 25 °C, COUT = 5.6 µF Ceramic, IOUT = 1 mA, Unless Otherwise Noted)

Figure 11. Noise Spectrum

Figure 13. Line Response with 10 mA Load

Figure 15. Load Transient – 1 mA/40 mA

Figure 12. Line Response with 1 mA Load

Figure 14. Line Response with 100 mA Load

Figure 16. Load Transient – 1 mA/80 mA

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Typical Performance Characteristics

(VIN = VOUT + 1 V, TA = 25 °C, COUT = 5.6 µF Ceramic, IOUT = 1 mA, Unless Otherwise Noted)

Figure 17. Power-Up with 1 mA Load

Figure 19. Power-Up with 10 mA Load

Figure 21. Power-Up with 100 mA Load

Figure 18. Turn-On with 1 mA Load

Figure 20. Turn-On with 10 mA Load

Figure 22. Turn-On with 100 mA Load

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Figure 23. AAT3221/3222 Functional Block Diagram

Functional Description

The AAT3221 and AAT3222 are intended for LDO regulator

applications where output current load requirements range from

no load to 150 mA. The advanced circuit design of the

AAT3221/3222 has been optimized for very low quiescent or

ground current consumption, making these devices ideal for use

in power management systems for small battery-operated

devices.

The typical quiescent current level is just 1.1 µA. Both devices

also contain an enable circuit that 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

1 µA from the input supply.

The LDO also demonstrates excellent Power Supply Ripple

Rejection (PSRR), and load and line transient response

characteristics. The AAT3221/3222 high performance LDO

regulators are especially well suited for circuit applications that

are sensitive to load circuit power consumption and extended

battery life.

The LDO regulator output has been specifically optimized to

function with low-cost, low Equivalent Series Resistance (ESR)

ceramic capacitors. However, the design allows for operation with

a wide range of capacitor types.

The AAT3221/3222 have complete short-circuit and thermal

protection. The integral combination of these two internal

protection circuits gives each device a comprehensive safety

system to guard against extreme adverse operating conditions.

Device power dissipation is limited to the package type and

thermal dissipation properties. Refer to the Thermal

Considerations and High Output Current Applications section of

this document for details on device operation at maximum output

load levels.

Application Information

To ensure that the maximum possible performance is obtained

from the AAT3221 or AAT3222, please refer to the following

application recommendations.

Input Capacitor

A 1 µF 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 AAT3221/3222 are physically

located more than one or two centimeters from the input power

source, a CIN capacitor is needed for stable operation. CIN should

be located as closely to the device VIN pin as practically possible.

CIN values greater than 1 µF offer superior input line transient

response and helps to maximize the power supply ripple

rejection.

Ceramic, tantalum, or aluminum electrolytic capacitors may be

selected for CIN, as there is no specific capacitor ESR

requirement. For 150 mA LDO regulator output operation, ceramic

capacitors are recommended for CIN due to their inherent

capability over tantalum capacitors to withstand input current

surges from low impedance sources such as batteries in portable

devices.

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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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 AAT3221/3222 have been specifically designed to function

with very low ESR ceramic capacitors. Although the devices are

intended to operate with these low ESR capacitors, they are

stable over a wide range of capacitor ESRs. Therefore, they can

also work with some higher ESR tantalum or aluminum

electrolytic capacitors. However, for best performance, ceramic

capacitors are recommended.

The value of COUT typically ranges from 0.47 µF to 10 µF;

however, 1 µF is sufficient for most operating conditions.

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.

The total output capacitance required can be calculated using the

following formula:

Where:

∆I = maximum step of output current

∆V = maximum excursion 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 or AAT3222 at room temperature. The increased

capacitor value is recommended if tight output tolerances must

be maintained over extreme operating conditions and maximum

operational temperature excursions. If tantalum or aluminum

electrolytic capacitors are used, the capacitor value should be

increased to compensate for the substantial ESR inherent to these

capacitor types.

Capacitor Characteristics

Ceramic composition capacitors are highly recommended over all

other types of capacitors for use with the AAT3221/3222.

Ceramic capacitors offer many advantages over their tantalum

and aluminum electrolytic counterparts. A ceramic capacitor

typically has a very low ESR, a lower cost, 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.

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.

Ceramic Capacitor Materials

Ceramic capacitors less than 0.1 µF are typically made from NPO

or C0G materials. NPO and C0G materials have a typically tight

tolerance and are very stable over temperature ranges. Larger

capacitor values are typically composed of X7R, X5R, Z5U, and

Y5V dielectric materials. Large ceramic capacitors, typically

greater than 2.2 µF, are 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 temperature range of the

device.

A 2.2 µF, Y5V capacitor could be reduced to 1 µF over the full

operating temperature 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%.

Capacitor area is another contributor to ESR. Capacitors that are

physically large in size have a lower ESR when compared to a

smaller sized capacitor of equivalent material and capacitance

value. These larger devices can also improve circuit transient

response when compared to an equal value capacitor in a smaller

package size.

Consult capacitor vendor Data Sheets carefully when selecting

capacitors for use with LDO regulators.

Enable Function

The AAT3221/3222 devices feature 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 V. A logic low signal is asserted when the voltage on the EN

pin falls below 0.8 V. For example, the active high versions of the

AAT3221 and AAT3222 turns 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 AAT3221/3222 can tie VIN to EN to remain on).

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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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 activate when the output load demand

exceeds the maximum rated output.

If a short-circuit condition was to continually draw more than the

current limit threshold, the LDO regulator output voltage drops to

a level necessary to supply the current demanded by the load.

Under short-circuit or other over-current operating conditions, the

output voltage drops and the device die temperature rapidly

increases.

Once the regulator’s power dissipation capacity is exceeded and

the internal die temperature reaches approximately 140 °C, the

system thermal protection circuit becomes active. The internal

thermal protection circuit actively turns off the LDO regulator

output pass device to prevent the possibility of over-temperature

damage. The LDO regulator output remains in a shutdown state

until the internal die temperature falls back below the 140 °C trip

point.

The interaction between the short-circuit and thermal protection

systems allows the LDO regulator to withstand indefinite short-

circuit conditions without sustaining permanent damage.

No-Load Stability

The AAT3221 and AAT3222 are designed to maintain output

voltage 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 section of this

document for recommended typical output capacitor values.

Thermal Considerations and High Output Current

Applications

The AAT3221/3222 are designed to deliver a continuous output

load current of 150 mA under normal operating conditions. The

limiting characteristic for the maximum output load safe operating

area is essentially package power dissipation and the internal

preset thermal limit of the device.

To obtain high operating currents, careful device layout and

circuit operating conditions need to be taken into account. The

following discussion assumes that the LDO regulator is mounted

on a printed circuit board using the minimum recommended

footprint, and the printed circuit board is

0.062-inch thick FR4 material with one ounce copper.

At any given ambient temperature (TA), the maximum package

power dissipation can be determined by the following equation:

Constants for the AAT3221/3222 are TJ(MAX), the maximum

junction temperature for the device, which is 125 °C, and

QJA = 150 °C/W, the package thermal resistance. Typically, the

maximum package power is calculated at the maximum operating

temperature where TA = 85 °C, and under normal ambient

conditions TA = 25 °C. Given TA = 85 °C, the maximum package

power dissipation is 267 mW. At TA = 25 °C, the maximum

package power dissipation is 667 mW.

The maximum continuous output current for the AAT3221/3222 is

a function of the package power dissipation and the input-to-

output voltage drop across the LDO regulator. Refer to the

following simple equation:

For example, if VIN = 5 V, VOUT = 2.5 V and TA = 25 °C,

IOUT(MAX) < 267 mA. The output short-circuit protection threshold

is set between 150 mA and 300 mA. If the output load current

were to exceed 267 mA or if the ambient temperature were to

increase, the internal 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 protection circuit would only

activate after a short-circuit event occurred on the LDO regulator

output.

To determine the maximum input voltage for a given load current,

refer to the following equation. This calculation accounts for the

total power dissipation of the LDO regulator, including that caused

by ground current.

This formula can be solved for VIN to determine the maximum

input voltage.

The following is an example of the AAT3221 or AAT3222 set for a

2.5 V output:

VOUT = 2.5 V

IOUT = 150 mA

IGND = 1.1 µA

From the discussion above, PD(MAX) was determined to equal

667 mW at TA = 25 °C. Therefore, the AAT3221/3222 can sustain

a constant 2.5 V output at a 150 mA load current as long as VIN ≤

6.95 V at an ambient temperature of 25 °C. The maximum input

operating voltage is 5.5 V for the AAT3221/3222. Therefore, at

25 °C, the device would not have any thermal concerns or

operational VIN(MAX) limits.

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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This situation can be different at 85 °C. The following is an

example for an AAT3221/3222 set for a 2.5 V output at 85 °C:

VOUT = 2.5 V

IOUT = 150 mA

IGND = 1.1 µA

From the discussion above, PD(MAX) was determined to equal

267 mW at TA = 85 °C.

Higher input-to-output voltage differentials can be obtained with

the AAT3221/3222, 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 = 5.0 V while

VOUT = 2.5 V at a 150 mA load and TA = 85 °C. VIN is greater than

4.28 V, which is the maximum safe continuous input level for

VOUT = 2.5 V at 150 mA 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:

IGND = 1.1 µA

IOUT = 150 mA

VIN = 5.0 V

VOUT = 2.5 V

PD(MAX) is assumed to be 267 mW.

For a 150 mA output current and a 2.5 V drop across the

AAT3221/3222 at an ambient temperature of 85 °C, the

maximum on-time duty cycle for the device is 71.2%.

The following family of curves shows the safe operating area for

duty-cycled operation from ambient room temperature to the

maximum operating level.

Figure 24: Device Duty Cycle vs Voltage Drop

(VOUT = 2.5 V @ 25 °C)

Figure 25: Device Duty Cycle vs Voltage Drop

(VOUT = 2.5 V @ 50 °C)

Figure 26: Device Duty Cycle vs Voltage Drop

(VOUT = 2.5 V @ 85 °C)

High Peak Output Current Applications

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 calculate the

power dissipation at the nominal continuous level, then factor in

the additional power dissipation due to the short duration, high-

current peaks.

For example, a 2.5 V system using an AAT3221/2IGV-2.5-T1

operates at a continuous 100 mA load current level and has short

150 mA current peaks. The current peak occurs for

378 µs out of a 4.61 ms period. It will be assumed the input

voltage is 5.0 V.

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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First, the current duty cycle percentage must be calculated:

% Peak duty cycle: x/100 = 378 µs/4.61 ms

% Peak duty cycle = 8.2%

The LDO regulator is under the 100 mA load for 91.8% of the

4.61 ms period and have 150 mA peaks occurring for 8.2% of the

time. Next, the continuous nominal power dissipation for the

100 mA load should be determined then multiplied by the duty

cycle to conclude the actual power dissipation over time.

PD(MAX) = (VIN – VOUT) IOUT + (VIN × IGND)

PD(100mA) = (5.0 V – 2.5 V) Х 100 mA + (5.0 V × 1.1 μA)

PD(100mA) = 250 mW

PD(91.8%D/C) = %DC · PD(100mA)

PD(91.8%D/C) = 0.918 × 250 mW

PD(91.8%D/C) = 229.5 mW

The power dissipation for a 100 mA load occurring for 91.8% of

the duty cycle is 229.5 mW. Now, the power dissipation for the

remaining 8.2% of the duty cycle at the 150 mA load can be

calculated:

PD(MAX) = (VIN – VOUT) IOUT + (VIN × IGND)

PD(150MA) = (5.0 V – 2.5 V) × 150 mA + (5.0 V × 1.1 μA)

PD(150mA) = 375 mW

PD(8.2%D/C) = %DC × PD(150mA)

PD(8.2%D/C) = 0.082 × 375 mW

PD(8.2%D/C) = 30.75 mW

The power dissipation for a 150 mA load occurring for 8.2% of the

duty cycle will be 30.75 mW. Finally, the two power dissipation

levels can be summed to determine the total true power

dissipation under the varied load:

PD(total) = PD(100 mA) + PD(150 mA)

PD(total) = 229.5 mW + 30.75 mW

PD(total) = 260.25 mW

The maximum power dissipation for the AAT3221/3222 operating

at an ambient temperature of 85 °C is 267 mW. The device in this

example has a total power dissipation of 260.25 mW. This is

within the thermal limits for safe operation of the device.

Printed Circuit Board Layout Recommendations

To obtain the maximum performance from the AAT3221/3222

LDO regulator, very careful attention must be considered in

regard to the printed circuit board layout. If grounding

connections are not properly made, power supply ripple rejection

and LDO regulator transient response can be compromised.

The LDO regulator external capacitors CIN and COUT should be

connected as directly as possible to the ground pin of the LDO

regulator. For maximum performance with the AAT3221/3222,

the ground pin connection should then be made directly back to

the ground or common of the source power supply. 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.

Evaluation Board Description

The AAT3221 Evaluation Board schematic diagrams are provided

in Figures 27 and 28. The PCB layout is illustrated in Figures 29

and 30. Component values for the AAT3221 Evaluation Boards are

listed in Tables 5 and 6.

Package Information

Package dimensions are shown in Figures 31 (SOT23-5) and 33

(SC70JW-8), and tape and reel dimensions are provided in

Figures 32 (SOT23-5) and 34 (SC70JW-8).

Figure 27: AAT3221 (SOT23-5) Evaluation Board Schematic

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Figure 28: AAT3221 (SC70JW-8) Evaluation Board Schematic

Figure 29: AAT3221 (SOT23-5) Evaluation Board

Figure 30: AAT3221 (SC70JW-8) Evaluation Board

Table 5. AAT3221 (SOT23-5) Evaluation Board Bill of Materials (BOM)

Component Part Number Description Manufacturer

U1 AAT3221IGV-XX-T1 150 mA, NanoPower low dropout linear regulator Skyworks

R1 RC0603FR-07100KL Resistor, 100 kΩ, 1/10W, 1%, 0603 SMD Yageo

C1, C2 GRM31MR71E105K Cap Ceramic, 1µF, 1206 X7R, 25V, 10% Murata

Table 6. AAT3221 (SC70JW-8) Evaluation Board Bill of Materials (BOM)

Component Part Number Description Manufacturer

U1 AAT3221IJS-XX-T1 150 mA, NanoPower low dropout linear regulator Skyworks

R1,R2 RC0603FR-07100KL Resistor, 100 kΩ, 1/10W, 1%, 0603 SMD Yageo

C1,C2 GRM31MR71E105K Cap Ceramic, 1µF, 1206 X7R, 25V, 10% Murata

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Figure 31. AAT3221/3222 5-Pin SOT23-5 Package Dimensions

Figure 32. AAT3221/3222 Tape and Reel Dimensions (SOT23-5)

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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Figure 33. AAT3221 8-Pin SC70JW-8 Package Dimensions

Figure 34. AAT3221/3222 Tape and Reel Dimensions (SC70JW-8)

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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202251B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • May 17, 2013 17

Ordering Information

Output Voltage Enable Package Marking (Note 1) Part Number (Tape and Reel) (Note 2)

1.6V

Active high

SOT23-5

GYXYY AAT3221IGV-1.6-T1

1.7V GBXYY AAT3221IGV-1.7-T1

1.8V BBXYY AAT3221IGV-1.8-T1

1.9V CGXYY AAT3221IGV-1.9-T1

2.0V BLXYY AAT3221IGV-2.0-T1

2.3V FLXYY AAT3221IGV-2.3-T1

2.4V FMXYY AAT3221IGV-2.4-T1

2.5V AKXYY AAT3221IGV-2.5-T1

2.6V GPXYY AAT3221IGV-2.6-T1

2.7V GDXYY AAT3221IGV-2.7-T1

2.8V AQXYY AAT3221IGV-2.8-T1

2.85V BYXYY AAT3221IGV-2.85-T1

2.9V JCXYY AAT3221IGV-2.9-T1

3.0V ALXYY AAT3221IGV-3.0-T1

3.1V GVXYY AAT3221IGV-3.1-T1

3.3V AMXYY AAT3221IGV-3.3-T1

1.5V

SC70JW-8

CFXYY AAT3221IJS-1.5-T1

1.6V AAT3221IJS-1.6-T1

1.7V AAT3221IJS-1.7-T1

1.8V BBXYY AAT3221IJS-1.8-T1

1.9V CGXYY AAT3221IJS-1.9-T1

2.0V BLXYY AAT3221IJS-2.0-T1

2.3V FLXYY AAT3221IJS-2.3-T1

2.4V FMXYY AAT3221IJS-2.4-T1

2.5V AKXYY AAT3221IJS-2.5-T1

2.6V GPXYY AAT3221IJS-2.6-T1

2.7V GDXYY AAT3221IJS-2.7-T1

2.8V AQXYY AAT3221IJS-2.8-T1

2.85V BYXYY AAT3221IJS-2.85-T1

2.9V JCXYY AAT3221IJS-2.9-T1

3.0V ALXYY AAT3221IJS-3.0-T1

3.1V GVXYY AAT3221IJS-3.1-T1

3.2V LEXYY AAT3221IJS-3.2-T1

3.3V AMXYY AAT3221IJS-3.3-T1

3.5V BMXYY AAT3221IJS-3.5-T1

2.8V

SOT23-5

BIXYY AAT3222IGV-2.8-T1

2.9V AAT3222IGV-2.9-T1

2.8V Active low CXXYY AAT3221IGV-2.8-2 T1

Note 1:

XYY = assembly and date code.

Note

2: Sample stock is generally held on part numbers listed in BOLD.

DATA SHEET • AAT3221/AAT3222 150 mA NANOPOWERTM LDO LINEAR REGULATOR

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