AP1186
1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Features
General Description
• 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
• Packages: TO220-5L, TO263-5L
• Lead Free Finish/RoHS Compliant for Lead Free
products (Note 1)
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 a
switching regulator. One such application is the new graphic chip
sets that require anywhere from 2.4V to 2.7V supply.
Ordering Information
X X X
1186
AP
Package Vout
K5:TO263-5L
T5:TO220-5L
Note: 1. RoHS revision 13.2.2003. Glass and High Temperature Solder Exemptions Applied, see EU Directive Annex Notes 5 and 7.
Device
AP1186T5 T5 TO220-5L 50 -U NA NA
Lead-free
AP1186K5 K5 TO263-5L 50 -U 800/Tape & Reel -13
Lead-free
Note: 2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf
Package
Code
X -
Blank : Adj
15 : 1.5V
18 : 1.8V
25 : 2.5V
33 : 3.3V
50 : 5.0V
Packaging
(Note 2)
.
Lead Free
L : Lead Free Package
Tube 13” Tape and Reel
Quantity
Part Number
Suffix
Packing
-U : Tube
-13: Taping
Quantity
Part Number
Suffix
Typical Application
AP1186 Rev. 1 1 of 9 MARCH 2007
3V 5V
+
470uF
Vin
Vctrl
Vou
t
GND
Vsense
5
4
3
2
1
+
470uF
+
470uF
www.diodes.com © Diodes Incorporated
2.5
V
/1.5A
Block Diagram
Vin
AP1186
1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Vout
Vctrl
CURRENT
LIMIT
THERMAL
SHUTDOWN
Package Connect Diagram
5 PIN TO263 5 PIN TO220
FRONT VIEW
Vin
5
Vctrl
4
3
Vout
Adj(GND)
2
Vsense
1
Tab is Vout
+
+
-
1.25V
+
+
-
Vsense
Adj
FRONT VIEW
5
4
3
2
1
Tab is Vout
Vin
Vctrl
Vout
Adj(GND)
Vsense
Pin Descriptions
Name I/O Description
Vsense I
Adj
(GND)
Vout O
Vctrl I
Vin I
AP1186 Rev. 1 2 of 9 MARCH 2007
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.
A resistor divider from this pin to the Vout pin and ground sets the output voltage.
(GND only for fixed mode)
The output of the regulator. A minimum of 100uF capacitor must be connected from this pin to ground
to insure stability.
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 for the device to regulate. A minimum of
100uF capacitor must be connected from this pin to ground to insure stability.
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.
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T
AP1186
1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
Absolute Maximum Ratings
Symbol Parameter Rating Unit
Vin Input Voltage 16 V
Vctrl Control Input Voltage 18 V
PD Power Dissipation Internally Limited
TST Storage Temperature -65 to +150
TOP Operating Junction Temperature Range 0 to +150
Electrical Characteristics
Unless otherwise specified, these specifications apply over, Cin = 1uF, Cout = 10uF, and T
o
25
C. Vout = Vsense.
SYM. Parameter Test Condition Min. Typ. Max. Unit
Reference
V
REF
Voltage
AP1186-Adj
AP1186-1.5
AP1186-1.8
V
Output Voltage
out
AP1186-2.5
AP1186-3.3
AP1186-5.0
Line Regulation AP1186-XXX
AP1186-Adj
AP1186-1.5
AP1186-1.8
Load Regulation
AP1186-2.5
AP1186-3.3
AP1186-5.0
Dropout Voltage
(Vctrl-Vout)
Dropout Voltage
(Vin-Vout)
Vadj = 0V for all conditions below.
Vin = 2.05V, Io = 1.5A
Vadj = 0V for all conditions below.
Vctrl = 3V, Io = 1.5A
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
AP1186 Rev. 1 3 of 9 MARCH 2007
= 25oC,(VIN-V
A
V
= VIN+1V
ctrl
I
= 10mA, TA = 25oC, 2V≦VIN≦12V
OUT
= VIN+1V
V
ctrl
I
= 10mA, TA = 25oC, 2.3V≦VIN≦12V
OUT
V
= VIN+1V
ctrl
I
= 10mA, TA = 25oC, 3V≦VIN≦12V
OUT
V
= VIN+1V
ctrl
I
= 10mA, TA = 25oC, 3.8V≦VIN≦12V
OUT
= VIN+1V
V
ctrl
I
= 10mA, TA = 25oC, 5.5V≦VIN≦12V
OUT
V
= VIN+1V
ctrl
I
= 10mA, V
O
V
= VIN+1V
ctrl
0mA<Io<1.5A, T
– V
(V
IN
V
= 3V, 0mA<Io<1.5A, TA = 25oC
IN
V
= 4V
ctrl
V
= 3.3V, 0mA<Io<1.5A, TA = 25oC
IN
V
= 4.3V
ctrl
V
= 4V, 0mA<Io<1.5A, TA = 25oC
IN
V
= 5V
ctrl
V
= 5V, 0≦I
IN
T
= 25oC V
A
V
= 8V, 0≦I
IN
T
= 25oC V
A
) = 2V, V
OUT
ctrl
ctrl
) = 0.5V,IO = 10mA
OUT
+0.5V<VIN<12V
OUT
=25oC
A
= VIN + 1V
ctrl
≦1.5A, TA = 25oC ,
OUT
= 6V
≦1.5A, TA= 25oC ,
OUT
= 9V
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FIXED-MODE REGULATOR
o
C
o
C
= 0 to 150oC. Typical value refers to TA =
J
1.225 1.250 1.275 V
1.470 1.500 1.530
1.764 1.800 1.836
2.450 2.500 2.550
3.235 3.300 3.365
4.900 5.000 5.100
0.2 %
1 %
12 15 mV
15 18 mV
20 25 mV
26 33 mV
40 50 mV
1.23
0.26 0.38
V
V
V
AP1186
1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
Electrical Characteristics ( Continued )
Unless otherwise specified, these specifications apply over, Cin = 1uF, Cout = 10uF, and Tj = 0 to 150oC. Typical value refers
to Tj = 25
SYM. Parameter Test Condition Min. Typ. Max. Unit
Note: 3. AP1186-ADJ incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the allowable
maximum junction temperature.
o
C. Vout = Vsense.
Thermal
Regulation
Ripple Rejection
Control Pin
Current
30ms Pulse 0.01 0.02 %W
Vctrl = 5V, Vin = 5V, Io = 1.5A, Vadj = 0V, Tj = 25,
Vripple = 1Vpp at 120Hz
Vadj = 0V for all conditions below.
Vctrl = 2.75V, Vin = 2.05V, Io = 1.5A
Iadj Adjust Pin Current Vctrl = 2.75V, Vin = 2.05,Vadj = 0 50 150 µA
Thermal
ΘJC
Resistance
Junction-to-Case
TO263-5L: Control Circuitry/Power Transistor
TO220-5L: Control Circuitry/Power Transistor
FIXED-MODE REGULATOR
60 70 dB
6 25 mA
2.5
2.5
o
C/W
AP1186 Rev. 1 4 of 9 MARCH 2007
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1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
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
Vout = Vref (1+R2/R1) + Iadj * R2 where : Vref = 1.25V & Iadj=50uA Typically
AP1186
FIXED-MODE REGULATOR
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:
Vin
AP1186-ADJ
Vctrl
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 and 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 121Ω 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
Vin
Vctrl
Vin
Vctrl
AP1186-ADJ
Adj
Adj
Iadj=50uA
Vsense
Vout
Vsense
Vref
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.
Vout
R1
R1+
R2+
R
L
R2
AP1186 Rev. 1 5 of 9 MARCH 2007
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1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
Function Descriptions (Continued)
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 100mΩ and an output capacitance of 100uF to 1000uF.
Thermal Design
The AP1186-XXX incorporates an internal thermal shutdown that
protects the device when the junction temperature exceeds the
allowable maximum junction temperature. Although this device
can operate with junction temperatures in the range of 150
recommended that the selected heat sink be chosen such that
during maximum continuous load operation the junction
temperature is kept below this number. The example below
shows the steps in selecting the proper surface mount package.
Assuming, the following conditions:
Vout = 2.5V
o
C, it is
AP1186
FIXED-MODE REGULATOR
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.
Vin = 3.3V
Vctrl = 5V
Iout = 1.5A DC Avg.
Calculate the maximum power dissipation using the
following equation:
Pd = Iout*(Vin-Vout)+(Iout/60)*(Vctrl-Vout)
Pd = 2*(3.3-2.5)+(2/60)*(5-2.5) = 1.68W
Using table below select the proper package and the
amount of copper board needed.
Package Copper Area Θ
(oC/W) Max Pd ( Ta = 25oC ) Max Pd ( Ta = 45oC )
JA
TO263 Pad Size-1.4”X1.4” 25-45 2.4W-4.4W 2.0W-3.6W
Note: Above table is based on the maximum junction temperature of 135
the job.
o
C. As shown in the above table, any of the two packages will do
AP1186 Rev. 1 - 0 6 of 9 MARCH 2007
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Marking Information
(1) TO220-5L
1186-XX: Voltage
1186-15: 1.5V
1186-18: 1.8V
1186-25: 2.5V
1186-33: 3.3V
1186-50: 5.0V
AP1186
1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
( Top view )
Logo
1186-XX
XX XX X X
L: Lead Free Package
Internal code
Xth week: 01~52
Year:
FIXED-MODE REGULATOR
"01" = 2001
"02" = 2002
~
(2) TO263-5L
1186-XX: Voltage
1186-15: 1.5V
1186-18: 1.8V
1186-25: 2.5V
1186-33: 3.3V
1186-50: 5.0V
(Top view)
1186- XX
X X X X X X
Logo
L: Lead Free Package
Internal Code
Xth Week: 01~52
Year:
"01" = 2001
"02" = 2002
~
AP1186 Rev. 1 7 of 9 MARCH 2007
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Package Information
(1) Package Type: TO220-5L
AP1186
1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1186 Rev. 1 8 of 9 MARCH 2007
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1.5A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
Package Information (Continued)
(2) Package Type: TO263-5L
AP1186
FIXED-MODE REGULATOR
IMPORTANT NOTICE
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further
notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither
does it convey any license under its patent rights, nor the rights of others. The user of products in such applications shall assume all risks of such use and will
agree to hold Diodes Incorporated and all the companies whose products are represented on our website, harmless against all damages.
LIFE SUPPORT
Diodes Incorporated products are not authorized for use as critical components in life support devices or systems without the expressed written approval of the
President of Diodes Incorporated.
AP1186 Rev. 1 9 of 9 MARCH 2007
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