
4
APE8800
Advanced Power
Electronics Corp.
BLOCK DIAGRAM
Error
Amp
Current
Limit
Thermal
Shutdown
_
__
_+
++
+
Vref 1.2V
VIN VOUT
GND
RSEN
PMOS
R1
R2
Figure 3. Block Diagram of APE8800
APPLICATION INFORMATION
The APE8800 series are low dropout linear
regulators that could provide 300mA output current
at dropout voltage about 300mV. Besides, current
limit and on chip thermal shutdown features provide
protection against any combination of overload or
ambient temperature that could exceed junction
temperature.
1.Output and Input Capacitor
The APE8800 regulator is designed to be stable
with a wide range of output capacitors. The ESR of
the output capacitor affects stability. Larger value
of the output capacitor decreases the peak
deviations and provides to improve transition
response for larger current changes.
The capacitor types (aluminum, ceramic, and tant-
alum) have different characterizations such as
temperature and voltage coefficients. All ceramic
capacitors are manufactured with a variety of
dielectrics, each with different behavior across
temperature and applications. Common dielectrics
used are X5R, X7R and Y5V. It is recommended to
use 1uF to 10uF X5R or X7R dielectric ceramic
capacitors with 30mΩ to 50mΩ ESR range betw-
een device outputs to ground for transient stability.
The APE8800 is designed to be stable with low
ESR ceramic capacitors and higher values of
capacitors and ESR could improve output stability.
So the
ESR of output capacitor is very important beca-
use it generates a zero to provide phase lead
for loop stability.
There are no requirements for the ESR on the
input capacitor, but its voltage and temperature
coefficient have to be considered for device
application environment.
2.Protection Features
In order to prevent overloading or thermal cond-
ition from damaging the device, APE8800
regulator has internal thermal and current
limiting functions designed to protect the device.
It will rapidly shut off PMOS pass element
during overloading or over temperature
condition.
3.Thermal Consideration
The power handling capability of the device will
be limited by maximum operation junction temp-
erature (125°C). The power dissipated by the
device will be estimated by PD = IOUT ×
(VIN-VOUT). The power dissipation should be
lower than the maximum power dissipation
listed in “Absolute Maximum Ratings” section.