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Rev.1.6.Nov.14, 2019

AX6646/A



APPLICATION CIRCUIT

EN

ON

OFF

VIN

VOUT

GND

IN

C

VIN

OUT

C

AX6646/A

1uF

1uF

OUT

V

EN

FB

R1

R2

VOUT=VFB*(1+R1/R2)

VFB= 0.8V

R2 Range=50K~300K



FUNCTION DESCRIPTIONS

A minimum of 1µF capacitor must be connected from VOUT to ground to insure stability.

Typically a large storage capacitor is connected from VIN to ground to ensure that the input

voltage does not sag below the minimum dropout voltage during the load transient response.

This pin must always be dropout voltage higher than VOUT in order for the device to regulate

properly.

Enable Function

The AX6646/A features an LDO regulator enable/disable function. To assure the LDO

regulator will switch on; the EN turn on control level must be greater than 2.0 volts. The LDO

regulator will go into the shutdown mode when the voltage on the EN pin falls below 0.8

volts. For to protecting the system, the AX6646/A have a quick-discharge function. If the

enable function is not needed in a specific application, it may be tied to VIN to keep the LDO

regulator in a continuously on state.

FB Function

The output is an adjustable version, the FB voltage is 0.8V. The output voltage can be

set by outside resistances. The output voltage, VOUT, is then given by the following equation:

VOUT = 0.8 (1 + R1/R2)

For the reasons of reducing power dissipation and loop stability, R2 is recommending

to choose 50K~300KΩ.