AP1186
1.5A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
Electrical Characteristics
Unless otherwise specified, these specifications apply over, Cin=1uF, Cout=10uF, and Tj=0 to 150 C. Typical value refer to Tj=25 C.
Vout = Vsense.
o
o
SYM.
Parameter
Thermal
Regulation
Ripple Rejection
Test Condition
30ms Pulse
Min.
Typ. Max. Unit
0.01
0.02
%W
dB
25
150
o
Vctrl =5V, Vin=5V, Io=1.5A, Vadj=0V, Tj=25,
Vripple=1Vpp at 120Hz
Control Pin
Vadj=0V for all conditions below.
Current
Vctrl=2.75V, Vin=2.05V, Io=1.5A
Iadj Adjust Pin Current Vctrl=2.75V, Vin=2.05,Vadj=0
Thermal
TO-263: Control Circuitry/Power Transistor
Θ
JC
Resistance
TO-220: Control Circuitry/Power Transistor
Junction-to-Case
60
70
6
50
2.5
2.5
mA
µA
C/W
NOTE:
AP1186-ADJ incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the allowable
maximum junction temperature.
Package
Max Pd.
TO-263/TO-220 2.4W~4.4W
With heat sink or amount of copper board needed.
Functional Descriptions
Introduction
The AP1186 regulator is a 5-terminal device
designed specifically to provide extremely low
dropout voltages comparable to the PNP type
without the disadvantage of the extra power
dissipation due to the base current associated with
PNP regulators. This is done by bringing out the
control pin of the regulator that provides the base
current to the power NPN and connecting it to a
voltage that is greater than the voltage present at
the Vin pin. This flexibility makes the AP1186 ideal
for applications where dual inputs are available
such as a computer motherboard with an ATX style
power supply that provides 5V and 3.3V to the
board. One such application is the new graphic chip
sets that require anywhere from 2.4V to 2.7V supply.
The AP1186-ADJ can easily be programmed with
the addition of two external resistors to any voltages
within the range of 1.25V to 15.5V. Another major
requirement of these graphic chips is the need to
switch the load current from zero to several amps in
tens of nanoseconds at the processor pins, which
translates to an approximately 300 to 500ns of
current step at the regulator. In addition, the output
voltage tolerances are also extremely tight and they
include the transient response as part of the
specification.
The AP1186 is specifically designed to meet the
fast current transient needs as well as providing an
accurate initial voltage, reducing the overall system
cost with the need for fewer number of output
capacitors. Another feature of the device is its true
remote sensing capability that allows accurate
voltage setting at the load rather than at the device.
Output Voltage Setting
The AP1186-ADJ can be programmed to any
voltages in the range of 1.25V to 15.5V with the
addition of R1 and R2 external resistors according
to the following formula:
Anachip Corp.
www.anachip.com.tw
4/8
Rev.1.1 Sep.7, 2004
ANACHIP [ ANACHIP CORP ]
