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AS1363

Datasheet - A p p l i c a t i o n I n f o r m a t i o n

9 Application Information

Capacitor Selection and Regulator Stability

Input and output capacitors are required for stable operation of the AS1363 over the full temperature range and with

board trace inductance.

Reduce noise and improve load-transient response, stability, and power supply rejection by using larger output capac-

itors, such as 10µF.

and output noise. Use output capacitors with an ESR of 0.1

Ω or less to ensure stability and optimum transient

response. Surface-mount ceramic capacitors have very-low ESR and are commonly available in values up to 10µF.

Noise, Power Supply Rejection Ratio, and Transient Response

The AS1363 is designed to operate with low dropout voltages and low quiescent currents in battery-powered systems

while still maintaining good noise response, transient response, and AC rejection. See Typical Operating Characteris-

tics on page 6 for a plot of power-supply rejection ratio (PSRR) versus frequency. When operating from noisy sources,

improved supply-noise rejection and transient response can be achieved by increasing the values of the input and out-

put bypass capacitors and through passive filtering techniques.

Dropout Voltage

Because the AS1363 uses a P-channel MOSFET pass transistor, its dropout voltage is a function of drain-to-source

Note: The AS1363 ground current remains below 200µA in dropout.

(EQ 4)

V

DROPOUT

V

IN

V

OUT

–

R

DS ON

()

I

OUT

×

==