ACE555

400mA LDO Dropout Voltage Regulator

VER 1.2

4

Detailed Description

ACE555 is a series of low dropout voltage, three terminal regulators. Its application circuit is very simple:

the fixed version only needs two capacitors and the adjustable version only needs two resistors and two

capacitors to work. It is composed of some modules including start-up circuit, bias circuit, bandgap,

thermal shutdown, current limit, power transistors and its driver circuit and so on.

The thermal shut down and current limit modules can assure chip and its application system working

safety when the environment temperature is larger than 140

or output current is larger than 600mA.

℃

The bandgap module provides stable reference voltage, whose temperature coefficient is compensated

by careful design considerations. The temperature coefficient is under 100ppm/ . And the accuracy of

℃

output voltage is guaranteed by trimming technique,

Typical Application

ACE555 has an adjustable version and five fixed versions, Chart1 is its typical application.

ACE555

Vin

Vin

Vout

Vout

GND

+

10uF

+

22uF

Cin

Cout

Application Hints

1.Recommend using 10uF tan capacitor as bypass capacitor(C1) for all application circuit.

2.Recommend using 22uF tan capacitor to assure circuit stability.

3.Using a bypass capacitor(CAdj) between the adjust terminal and ground can improve ripple rejection,

This bypass capacitor prevents ripple from being amplified as the output voltage is increased.The

impedance of CAdj should be less than the resistor’s(R1) which is between output and adjust pins to

prevent ripple from being amplified at any ripple frequency. As R1 is normally in the range of 200Ω~350

Ω

,the value of CAdj should satisfy this equation:2*Fripple*CAdj<R1. Recommend using 10uF tan

capacitor.