AME
High PSRR, Low Quiescent Current,
150mA Dual CMOS LDO
AME8755
n Detailed Description
The AME8755 contains two PMOS pass transistors, a
reference voltage source, error amplifiers, over current
protection, and thermal shutdown. The P-channel pass
transistor receives data from the error amplifier, over cur-
rent limit, and thermal protection circuits. During normal
operation, the error amplifier compares the output voltage
to a precision reference. The output voltages are con-
trolled and stabilized by a system of negative feedback.
The AME8755 requires an output capacitor connected
between the output and ground to stabilize the internal
control loops. The minimum recommended output ca-
pacitor is 1mF. The IC's internal circuitry can be turned on
and off via the signal from the EN1 and EN2 pins, for
example: OUT1 is turned on when EN1 is greater than
1.4V. And OUT1 is turned off when EN1 is less than
0.4V, resulting in greatly reduced power consumption,
same operation for EN2 and OUT2.
The AME8755's over current limit and thermal shutdown
protection prevent the IC from damaging. The internal
over current protection helps protect the regulator during
fault conditions. During over current protection, the out-
put will be pulled down and source a nearly fixed amount
of current that is largely independent of the output volt-
age. Thermal shutdown protection disables both outputs
when the junction temperature of either channel rises to
approximately 160oC, allowing the device to cool. When
the junction temperature cools to approximately 140oC,
the output circuitry is again enabled. This limits the dis-
sipation of the regulator, protecting it from damage due to
over heating.
Rev. A.01
9
AMETHERM [ AMETHERM CIRCUIT PROTECTION THERMISTORS ]
