MIC5200 Datasheet, PDF (12/24 Pages) Micrel Semiconductor – 100mA Low-Dropout Voltage Regulator Preliminary Information

MIC5200
4.0 APPLICATION INFORMATION
4.1 External Capacitors
A 1 μF capacitor is recommended between the
MIC5200 output and ground to prevent oscillations due
to instability. Larger values serve to improve the
regulator's transient response. Most types of tantalum
or aluminum electrolytics will be adequate; film types
will work, but are costly and therefore not
recommended. Many aluminum electrolytics have
electrolytes that freeze at about –30°C, so solid
tantalum capacitors are recommended for operation
below –25°C. The important parameters of the
capacitor are an effective series resistance of about 5Ω
or less and a resonant frequency above 500 kHz. The
value of this capacitor may be increased without limit.
At lower values of output current, less output
capacitance is required for output stability. The
capacitor can be reduced to 0.47 μF for current below
10 mA or 0.33 μF for currents below 1 mA. A 1 μF
capacitor should be placed from the MIC5200 input to
ground if there is more than 10 inches of wire between
the input and the AC filter capacitor or if a battery is
used as the input.
The MIC5200 will remain stable and in regulation with
no load in addition to the internal voltage divider, unlike
many other voltage regulators. This is especially
important in CMOS RAM keep-alive applications.
When used in dual supply systems where the regulator
load is returned to a negative supply, the output voltage
must be diode clamped to ground.
4.2 ENABLE Input
The MIC5200 features nearly zero OFF mode current.
When the ENABLE input is held below 0.7V, all internal
circuitry is powered off. Pulling this pin high (over 2.0V)
re-enables the device and allows operation. The
ENABLE pin requires a small amount of current,
typically 15 μA. While the logic threshold is TTL/CMOS
compatible, ENABLE may be pulled as high as 30V,
independent of the voltage on V_IN.
DS20005578A-page 12
 2016 Microchip Technology Inc.