1.5A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
AP1186
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of
this product. No rights under any patent accompany the sale of the product.
Rev.1.1 Sep.7, 2004
1/8
Feature
Adjustable or Fixed output voltage 1.5V, 1.8V,
2.5V, 3.3V, 5.0V
0.5V Maximum Dropout voltage at 1.5A Load
current
Built-in Thermal Shutdown
Output Current Limiting
Fast transient response
Good noise rejection
Package : TO220-5L, TO263-5L
General Description
AP1186 is a 1.5A regulator with extremely low
dropout voltage. This product is specifically
designed to provide well regulated supply for
applications requiring 2.8V or lower voltages from
3.3V ATX power supplies where high efficiency of a
switcher can be achieved without the cost and
complexity associated with switching regulator. One
such application is the new graphic chip sets that
require anywhere from 2.4V to 2.7V supply.
Ordering Information
K5:TO-263-5L
T5:TO-220-5L
AP 1186 X X X X
Package
Vout
Blank : Adj
15 : 1.5V
18 : 1.8V
25 : 2.5V
33 : 3.3V
50 : 5.0V
Packing
Blank : Tube
A : Taping& Reel
Low Dropout Regulator
Lead Free
Blank : Normal
L : Lead Free Package
Typical Application
470uF
+
470uF
+
2.5V/1.5A
3
2
1
Vout
Vsense
GND
Vctrl
Vin
4
5
3V
5V
470uF
+
1.5A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
AP1186
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Sep.7, 2004
2/8
Block Diagram
THERMAL
SHUTDOWN
Vout
Adj
1.25V
+
CURRENT
LIMIT
Vin
+
-
+
+
-
Vsense
Vctrl
Package Connect Diagram
5 PIN TO263
5 PIN TO220
Tab is Vout
FRONT VIEW
Tab is Vout
FRONT VIEW
Vout
Vsense
Adj(GND)
Vctrl
Vin
5
2
1
4
3
3
2
1
Vout
Vsense
Adj(GND)
Vctrl
Vin
4
5
Pin Descriptions
Name
I/O
Description
Adj
(GND)
A resistor divider from this pin to the Vout pin and ground sets the output voltage.
(GND only for fixed mode)
Vsense I
This pin is the positive side of the reference that allows remote load sensing to
achieve excellent load regulation. A minimum of 10uF capacitor must be connected
from this pin to ground to insure stability.
Vin I
The input of the regulator. Typically a large storage capacitor is connected from this
pin to ground to insure that the input voltage does not sag below the minimum
dropout voltage during the load transient response. This pin must always be higher
than Vout in order for the device to regulate.
Vctrl I
This pin is the supply pin for the internal control circuit as well as the base drive for
the pass transistor. This pin must always by higher than the Vout pin in order the
device to regulate. A minimum of 100uF capacitor must be connected from this pin
to ground to insure stability.
NC
Not
used.
Vout O
The output of the regulator. A minimum of 100uF capacitor must be connected from
this pin to ground to insure stability.
1.5A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
AP1186
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Sep.7, 2004
3/8
Absolute Maximum Ratings
Symbol
Parameter
Rating
Unit
Vin Input
Voltage
16
V
Vctrl
Control Input Voltage
18
V
PD
Power Dissipation
Internally Limited
T
ST
Storage Temperature
-65 to +150
oC
T
OP
Operating Junction Temperature Range
0 to +150
oC
Electrical Characteristics
Unless otherwise specified, these specifications apply over, Cin=1uF, Cout=10uF, and Tj=0 to 150
o
C. Typical value refer to Tj=25
o
C.
Vout = Vsense.
SYM.
Parameter
Test Condition
Min. Typ. Max. Unit
V
REF
Reference Voltage AP1186-Adj
T
J
=25
o
C,(V
IN
-V
OUT
)=0.5V,I
O
=10mA
V
ctrl
=V
IN
+1V
1.225 1.250 1.275
V
AP1186-1.5
I
OUT
= 10mA, T
J
= 25
o
C, 2VV
IN
12V
V
ctrl
=V
IN
+1V
1.470 1.500 1.530
AP1186-1.8
I
OUT
= 10mA, T
J
= 25
o
C, 2.3VV
IN
12V
V
ctrl
=V
IN
+1V
1.764 1.800 1.836
AP1186-2.5
I
OUT
= 10mA, T
J
= 25
o
C, 3VV
IN
12V
V
ctrl
=V
IN
+1V
2.450 2.500 2.550
AP1186-3.3
I
OUT
= 10mA, T
J
= 25
o
C, 3.8VV
IN
12V
V
ctrl
=V
IN
+1V
3.235 3.300 3.365
V
out
Output Voltage
AP1186-5.0
I
OUT
= 10mA, T
J
= 25
o
C, 5.5VV
IN
12V
V
ctrl
=V
IN
+1V
4.900 5.000 5.100
V
Line
Regulation AP1186-XXX
I
O
=10mA, V
OUT
+0.5V<V
IN
<12V
V
ctrl
=V
IN
+1V
0.2
%
AP1186-Adj
0mA<Io<1.5A, T
J
=25
o
C
(V
IN
V
OUT
) = 2V, V
ctrl
= V
IN
+ 1V
1
%
AP1186-1.5
V
IN
=3V, 0mA<Io<1.5A, T
J
=25
o
C
V
ctrl
=4V
12 15
mV
AP1186-1.8
V
IN
=3.3V, 0mA<Io<1.5A, T
J
=25
o
C
V
ctrl
=4.3V
15 18
mV
AP1186-2.5
V
IN
=4V, 0mA<Io<1.5A, T
J
=25
o
C
V
ctrl
=5V
20 25
mV
AP1186-3.3
V
IN
= 5V, 0I
OUT
1.5A, T
J
=25
o
C ,
T
J
=25
o
C V
ctrl
=6V
26 33
mV
Load
Regulation
AP1186-5.0
V
IN
= 8V, 0I
OUT
1.5A, T
J
=25
o
C ,
T
J
=25
o
C V
ctrl
=9V
40 50
mV
Dropout Voltage
(Vctrl-Vout)
Vadj=0V for all conditions below.
Vin=2.05V, Io=1.5A
1.23
V
Dropout Voltage
(Vin-Vout)
Vadj=0V for all conditions below.
Vctrl=3V, Io=1.5A
0.26
0.38
V
Current
Limit
Vctrl=3V,
Vin=2.05V,
Vo=100mV, Vadj=0V
1.6
A
Minimum Load
Current
Vctrl=5V, Vin=3.3V, Vadj=0V
5
10
mA
1.5A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
AP1186
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Sep.7, 2004
4/8
Electrical Characteristics
Unless otherwise specified, these specifications apply over, Cin=1uF, Cout=10uF, and Tj=0 to 150
o
C. Typical value refer to Tj=25
o
C.
Vout = Vsense.
SYM.
Parameter
Test Condition
Min. Typ. Max. Unit
Thermal
Regulation
30ms Pulse
0.01 0.02 %W
Ripple
Rejection
Vctrl =5V, Vin=5V, Io=1.5A, Vadj=0V, Tj=25,
Vripple=1Vpp at 120Hz
60 70 dB
Control Pin
Current
Vadj=0V for all conditions below.
Vctrl=2.75V, Vin=2.05V, Io=1.5A
6 25
mA
Iadj Adjust Pin Current Vctrl=2.75V, Vin=2.05,Vadj=0
50
150
A
JC
Thermal
Resistance
Junction-to-Case
TO-263: Control Circuitry/Power Transistor
TO-220: Control Circuitry/Power Transistor
2.5
2.5
o
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:
1.5A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
AP1186
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Sep.7, 2004
5/8
Functional Descriptions(Continued)
Vout = Vref (1+R2/R1) + Iadj * R2 where : Vref = 1.25V & Iadj=50uA Typically
AP1186-ADJ
Vin
Vctrl
Adj
Vout
Vsense
R1+
R2+
Vref
Iadj=50uA
The AP1186-ADJ keeps a constant 1.25V between
the Vsense pin and the Adj pin. By placing a
resistor R1 across these two pins and connecting
the Vsense ans Vout pin together, a constant
current flows through R1, adding to the Iadj current
and into the R2 resistor producing a voltage equal
to the (1.25/R1)*R2 + Iadj*R2. This voltage is then
added to the 1.25V to set the output voltage. This is
summarized in the above equation.
Since the minimum load current requirement of the
AP1186-ADJ is 10mA, R1 is typically selected to be
a 121 resistor so that it automatically satisfies this
condition. Notice that since the Iadj is typically in
the range of 50uA it only adds a small error to the
output voltage and should be considered when very
precise output voltage setting is required.
Load Regulation
Since the AP1186 has separate pins for the output
(Vout) and the sense (Vsense), it is ideal for
providing true remote sensing of the output voltage
at the load. This means that the voltage drops due
to parasitic resistance such as PCB traces between
the regulator and the load are compensated for
using remote sensing. Figure following shows a
typical application of the AP1186 with remote
sensing.
AP1186-ADJ
Vin
Vctrl
Vin
Vctrl
Vout
Vsense
Adj
R1
R2
R
L
Stability
The AP1186-XXX requires the use of an output
capacitor as part of the frequency compensation in
order to make the regulator stable. Typical designs
for the microprocessor applications use standard
electrolytic capacitors with typical ESR in the range
of 50 to 100m and an output capacitance of
100uF to 1000uF. Fortunately as the capacitance
increases, the ESR decreases resulting in a fixed
RC time constant. The AP1186-XXX takes
advantage of the phenomena in making the
overall regulator loop stable.
For most applications a minimum of 100uF
aluminum electrolytic capacitor insures both stability
and good transient response.
PDF 
ZIP