AME8800 Datasheet, PDF(13/20 Page) Analog Microelectronics

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

AME8800 Datasheet, PDF (13/20 Pages) Analog Microelectronics – 300mA CMOS LDO

◁

AME, Inc.

AME8800 / 8811

300mA CMOS LDO

n Detailed Description

The AME8800/8811 family of CMOS regulators con-

tain a PMOS pass transistor, voltage reference, error

amplifier, over-current protection, and thermal shut-

down.

The P-channel pass transistor receives data from the

error amplifier, over-current shutdown, and thermal pro-

tection circuits. During normal operation, the error am-

plifier compares the output voltage to a precision refer-

ence. Over-current and Thermal shutdown circuits be-

come active when the junction temperature exceeds

150oC, or the current exceeds 300mA. During thermal

shutdown, the output voltage remains low. Normal op-

eration is restored when the junction temperature drops

below 120oC.

The AME8800/8811 switches from voltage mode to cur-

rent mode when the load exceeds the rated output cur-

rent. This prevents over-stress. The AME8800/8811

also incorporates current foldback to reduce power dis-

sipation when the output is short circuited. This feature

becomes active when the output drops below 0.8 volts,

and reduces the current flow by 65%. Full current is

restored when the voltage exceeds 0.8 volts.

n External Capacitors

The AME8800/8811 is stable with an output capacitor

to ground of 2.2ÂµF or greater. Ceramic capacitors have

the lowest ESR, and will offer the best AC performance.

Conversely, Aluminum Electrolytic capacitors exhibit

the highest ESR, resulting in the poorest AC response.

Unfortunately, large value ceramic capacitors are com-

paratively expensive. One option is to parallel a 0.1uF

ceramic capacitor with a 10uF Aluminum Electrolytic.

The benefit is low ESR, high capacitance, and low over-

all cost.

A second capacitor is recommended between the input

and ground to stabilize VIN. The input capacitor should

be at least 0.1ÂµF to have a beneficial effect.

All capacitors should be placed in close proximity to

the pins. A "Quiet" ground termination is desirable.

This can be achieved with a "Star" connection.

▷