AAT3220IGY 查看數據表（PDF） - Skyworks Solutions

零件编号

产品描述 (功能)

比赛名单

AAT3220IGY

150mA NanoPower LDO Linear Regulator

Skyworks Solutions 

DATA SHEET

AAT3220

150mA NanoPowerTM LDO Linear Regulator

load current, refer to the following equation. This calcu-

lation accounts for the total power dissipation of the LDO

regulator, including that caused by ground current.

PD(MAX) = (VIN - VOUT)IOUT + (VIN ⋅ IGND)

This formula can be solved for VIN to determine the

maximum input voltage.

VIN(MAX) =

PD(MAX) + (VOUT ∙ IOUT)

IOUT + IGND

The following is an example for an AAT3220 set for a

3.0V output:

VOUT = 3.0V

IOUT = 150mA

IGND = 1.1µA

VIN(MAX)

=

500mW + (3.0V ∙ 150mA)

150mA + 1.1µA

VIN(MAX) = 6.33V

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

equal 500mW at TA = 25°C.

Thus, the AAT3220 can sustain a constant 3.0V output

at a 150mA load current as long as VIN is ≤ 6.33V at an

ambient temperature of 25°C. 5.5V is the maximum

input operating voltage for the AAT3220, thus at 25°C,

the device would not have any thermal concerns or

operational VIN(MAX) limits.

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

example for an AAT3220 set for a 3.0V output at 85°C:

VOUT = 3.0V

IOUT = 150mA

IGND = 1.1µA

VIN(MAX)

=

200mW + (3.0V ∙ 150mA)

150mA + 1.1µA

VIN(MAX) = 4.33V

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

equal 200mW at TA = 85°C.

Higher input-to-output voltage differentials can be

obtained with the AAT3220 while maintaining device

functions in the thermal safe operating area. To accom-

plish 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 = 3.0V at a 150mA load and TA = 85°C. VIN is great-

er than 4.33V, which is the maximum safe continuous

input level for VOUT = 3.0V 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:

IGND = 1.1µA

IOUT = 150mA

VIN = 5.0V

VOUT = 3.0V

%DC =

PD(MAX)

(VIN - VOUT) ∙ IOUT + (VIN ∙ IGND)

%DC =

200mW

(5.0V - 3.0V) ∙ 150mA + (5.0V ∙ 1.1µA)

%DC = 66.67%

PD(MAX) is assumed to be 200mW.

For a 150mA output current and a 2.0V drop across the

AAT3220 at an ambient temperature of 85°C, the maxi-

mum on-time duty cycle for the device would be

66.67%.

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

11

Share Link: