SAMHOP Microelectronics Corp.
SM1100
the highest ESR and resulting in the
poorest AC response.
Detailed Description
The SM1100 is 150mA CMOS LDO
designed with Low RDSON PMOS pass
a
In addition to the >1uF capacitor connect to
Vin, recommend to add a >0.1uF capacitor
between Vin to Ground to stabilize Vin.
transistor, Bandgap voltage reference, Error
amplifier, Current limit. The P-channel pass
transistor receives control signal from
the Error amplifier, Current limit circuits.
During normal operation, the Error
amplifier compares the output voltage to
an internal trimmed precision Bandgap
reference to regulate and output a preset
voltage.
Current Limit
SM1100 built-in with Current
Limit
protection circuit, which monitors and
controls the gate of the pass transistor
and limiting the output current to 300mA
(
Min.).
External Capacitor
Selection
Dropout Voltage
The SM1100 is stable with an output
capacitor to ground of 1uF or greater and >
100m ohm ESR. Ceramic or tantalum
capacitors can be used. The capacitor
with larger value and lower ESR provides
better PSRR and line-transient response.
Ceramic capacitors have the lowest ESR,
and will offer the best AC performance.
Aluminum Electrolytic capacitors present
Current flow through regulator’s pass PMOS
transistor cause Input-Output voltage drop, it
determines the lowest usable supply voltage.
The SM1100 PMOS pass switch low RDSON
only present 300mV dropout voltage at
100mA Iout, it further extend the battery
useful end-of-life voltage.
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SAMHOP [ SAMHOP MICROELECTRONICS CORP. ]
