L1913 Datasheet, PDF (8/9 Pages) Unisonic Technologies – 150mA LOW-DROPOUT LINEAR REGULATORS

L1913
Preliminary
CMOS IC
„ APPLICATIONS INFORMATION
Capacitor Selection and Regulator Stability
A 1µF capacitor on the input and a 1µF capacitor on the output are recommended for most applications of the U
TC L1913. To get a better supply-noise rejection and transient response, input capacitors with larger values and
lower ESR are needed. A higher-value input capacitor (10µF) may be necessary if large, fast transients are
anticipated and the device is located several inches from the power source.
Power-Supply Rejection and Operation from Sources Other than Batteries
The UTC L1913 is particularly designed to deliver low dropout voltages and low quiescent currents in battery-
powered systems. Power-supply rejection is 42dB at low frequencies. As the frequency increases above 20kHz, the
output capacitor is the major contributor to the rejection of power-supply noise.
When operating from sources other than batteries, improve supply-noise rejection and transient response by
increasing the values of the input and output capacitors, and using passive filtering techniques.
Input-Output (Dropout) Voltage
A regulator's minimum input-output voltage differential (or dropout voltage) determines the lowest usable supply
voltage. In battery-powered systems, this will determine the useful end-of-life battery voltage. Because the UTC
L1913 use a P-channel MOSFET pass transistor, their dropout voltage is a function of R_DS(ON) multiplied by the load
current.
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www.unisonic.com.tw
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