AME, Inc.
AME8822
High PSRR, 250mA CMOS LDO
n Detailed Description
n Enable
The AME8822 family of CMOS regulators contain a
PMOS pass transistor, voltage reference, error amplifier,
over-current protection, and thermal shutdown.
The Enable Pin is normally pull-high. When activated
pulled low, the PMOS pass transistor shuts off, and all
internal circuits are powered down. In this state, the stand
by current is less than 1mA. This pin can’ t be floating.
The P-channel pass transistor receives data from the
error amplifier, over-current shutdown, and thermal pro-
tection circuits. During normal operation, the error ampli-
fier compares the output voltage to a precision reference.
Over-current and thermal shutdown circuits become ac-
tive when the junction temperature exceeds 150oC, or
the current exceeds 250mA. During thermal shutdown,
the output voltage remains low. Normal operation is re-
stored when the junction temperature drops below 130oC.
The AME8822 switches from voltage mode to current
mode when the load exceeds the rated output current.
This prevents over-stress.
n External Capacitors
The AME8822 is stable with an output capacitor to
ground of 1mF or larger. Ceramic capacitors have the low-
est ESR, and will offer the best AC performance. Con-
versely, Aluminum Electrolytic capacitors exhibit the high-
est ESR, resulting in the poorest AC response.
A second capacitor is recommended between the in-
putandgroundtostabilizeVIN. The input capacitor should
be at least 1mF to have a beneficial effect.
10
Rev.D.05
AME [ ANALOG MICROELECTRONICS ]
