原标题：ADI ADP125低静态电流线性电源解决方案

　　ADI公司的ADP125是5.5V输入500mA输出电流的低静态电流CMOS线性电源稳压器,输入电压从2.3V到5.5V,500A电流时的压降为130mV,有固定输出和可调输出两种型号,可调输出从0.8 V 到 5.0 V,100kHz的PSRR为60dB，主要用在数码相机和音频设备，手持设备，自动读表(AMR),GPS和本地管理单元，医疗设备和POL.本文介绍了ADP125主要特性，ADP124/ADP125方框图，应用电路以及ADP124/ADP125评估板电路图和材料清单.

　　5.5 V Input, 500 mA, Low Quiescent Current, CMOS Linear Regulators

　　The ADP124/ADP125 are low quiescent current, low dropout linear regulators. They are designed to operate from an input voltage between 2.3 V and 5.5 V and to provide up to 500 mA of output current. The low 130 mV dropout voltage at a 500 mA load improves efficiency and allows operation over a wide input voltage range.

　　The low 210 μA of quiescent current with a 500 mA load makes the ADP124/ADP125 ideal for battery-operated portable equipment.

　　The ADP124 is capable of 31 fixed-output voltages from 1.75 V to 3.3 V. The ADP125 is the adjustable version of the device and allows the output voltage to be set between 0.8 V and 5.0 V by an external voltage divider.

　　The ADP124/ADP125 are specifically designed for stable operation with tiny 1 μF ceramic input and output capacitors to meet the requirements of high performance, space constrained applications.

　　The ADP124/ADP125 have an internal soft start that gives a constant start-up time of 350 μs. Short-circuit protection and thermal overload protection circuits prevent damage in adverse conditions. The ADP124/ADP125 are available in 8-lead exposed paddle MSOP and LFCSP packages. When compared with the standard MSOP and LFCSP packages, the exposed paddle MSOP and LFCSP packages have lower thermal resistance (θJA). The lower thermal resistance package allows the ADP124/ ADP125 to meet the needs of a variety of portable applications while minimizing the rise in junction temperature.

　　ADP125主要特性:

　　Input voltage supply range: 2.3 V to 5.5 V

　　500 mA maximum output current

　　Fixed and adjustable output voltage versions

　　1% initial accuracy

　　Up to 31 fixed-output voltage options available from 1.75 V to 3.3 V

　　Adjustable-output voltage range from 0.8 V to 5.0 V

　　Very low dropout voltage: 130 mV

　　Low quiescent current: 45 μA

　　Low shutdown current: <1 μA

　　Excellent PSRR performance: 60 dB at 100 kHz

　　Excellent load/line transient response

　　Optimized for small 1.0 μF ceramic capacitors

　　Current limit and thermal overload protection

　　Logic controlled enable

　　Compact 8-lead exposed paddle MSOP and LFCSP packages

　　ADP125应用:

　　Digital camera and audio devices

　　Portable and battery-powered equipment

　　Automatic meter reading (AMR) meters

　　GPS and location management units

　　Medical instrumentation

　　Point of load power

　　图1.ADP124内部方框图(固定输出)

　　图2.ADP125内部方框图(可调输出)

　　ADP124/ADP125评估板

　　评估板主要特性:

　　Input voltage range: 2.3 V to 5.5 V

　　Output current range: 0 mA to 500 mA

　　Output voltage accuracy: ±1%

　　Operating temperature range: −40℃ to +125℃

　　图3.ADP124/ADP125评估板电路图: LFCSP

　　图4.ADP125评估板电路图: MSOP

　　图5.ADP124评估板电路图:MSOP

　　评估板材料清单(BOM):