AAT3220IGY-3.0-T1 查看數據表（PDF） - Skyworks Solutions

零件编号

产品描述 (功能)

比赛名单

AAT3220IGY-3.0-T1

150mA NanoPower LDO Linear Regulator

Skyworks Solutions 

DATA SHEET

AAT3220

150mA NanoPowerTM LDO Linear Regulator

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

operating temperature range. This can cause problems

for circuit operation and stability. X7R and X5R dielec-

trics are much more desirable. The temperature toler-

ance of X7R dielectric is better than ±15%.

Capacitor area is another contributor to ESR. Capacitors,

which 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 circuit transient response when compared

to an equal value capacitor in a smaller package size.

Consult capacitor vendor datasheets carefully when

selecting capacitors for use with LDO regulators.

Short-Circuit and Thermal Protection

The AAT3220 is protected by both current limit and over-

temperature protection circuitry. The internal short-cir-

cuit current limit is designed to activate 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 out-

put voltage would 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 would drop and the AAT3220’s die temperature

would increase rapidly. Once the regulator’s power dis-

sipation capacity has been exceeded and the internal die

temperature reaches approximately 140°C the system

thermal protection circuit will become active. The inter-

nal thermal protection circuit will actively turn off the

LDO regulator output pass device to prevent the possibil-

ity of over-temperature damage. The LDO regulator

output will remain in a shutdown state until the internal

die temperature falls back below the 120°C trip point.

The combination and interaction between the short-cir-

cuit and thermal protection systems allows the LDO

regulator to withstand indefinite short-circuit conditions

without sustaining permanent damage.

No-Load Stability

The AAT3220 is designed to maintain output voltage

regulation and stability under operational no-load condi-

tions. 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

datasheet for recommended typical output capacitor val-

ues.

Thermal Considerations and

High Output Current Applications

The AAT3220 is designed to deliver a continuous output

load current of 150mA under normal operating condi-

tions. 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. In order to obtain high operating currents, care-

ful device layout and circuit operating conditions need to

be taken into account. The following discussions will

assume the LDO regulator is mounted on a printed cir-

cuit board utilizing 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 fol-

lowing equation:

PD(MAX)

=

TJ(MAX) -

ΘJA

TA

Constants for the AAT3220 are TJ(MAX), the maximum

junction temperature for the device which is 125°C and

QJA = 200°C/W, the package thermal resistance. Typically,

maximum conditions are calculated at the maximum

operating temperature where TA = 85°C; under normal

ambient conditions TA = 25°C. Given TA = 85°C, the

maximum package power dissipation is 200mW. At TA =

25°C, the maximum package power dissipation is

500mW.

The maximum continuous output current for the AAT3220

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:

IOUT(MAX) <

PD(MAX)

VIN - VOUT

For example, if VIN = 5V, VOUT = 3V and TA = 25°C, IOUT(MAX)

< 250mA. The output short-circuit protection threshold is

set between 150mA and 300mA. If the output load cur-

rent were to exceed 250mA or if the ambient tempera-

ture 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 will only activate after a short-

circuit event occurs on the LDO regulator output.

To determine the maximum input voltage for a given

10

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

202250A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 7, 2012

Share Link: