AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 1 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Features General Description
AP1184 is a 4A 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 the switch can be
achieved without the cost and complexity associated with
switching regulator. One such application is the new graphic
chipsets that requires anywhere from 2.4V to 2.7V supply.
• 0.85V maximum dropout voltage at 4A load current
• Built-in Thermal shutdown
• Output current limiting
• Adjustable or fixed output voltage1.5V, 1.8V, 2.5V,
3.3V, 5.0V
• Fast transient response
• Good noise rejection
• Packages: TO220-5L and TO263-5L
• Lead Free Finish/ RoHS Complian (Note 1)
Ordering Information
AP1184 XX -XX L X
Package Vout
K5 : TO263-5L
T5 : TO220-5L Blank : Adj
15 = 1.5V
18 = 1.8V
25 = 2.5V
33 = 3.3V
50 = 5.0V
Packing
U : Tube
13 : Tape & Reel
Lead Free
L : Lead Free
-
Tube 13” Tape and Reel
Device Package
Code Packaging
(Note 2) Quantity Part Number
Suffix Quantity Part Number
Suffix
AP1184K5XXL-U K5 TO263-5L 50 -U NA NA
AP1184K5XXL-13 K5 TO263-5L NA NA 800/Tape & Reel -13
AP1184T5XXL-U T5 TO220-5L 50 -U NA NA
Lead-free
Lead-free
Lead-free
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes.
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.
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 2 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Pin Assignments
TO263-5L
FRONT VIEW
Tab is Vout
3
2
1
Vout
Vsense
Adj(GND)
Vctrl
Vin
4
5
TO220-5L
Tab is Vout
FRONT VIEW
Vout
Vsense
Adj(GND)
Vctrl
Vin
5
2
1
4
3
Pin Numbers with standard type are for TO220-5L, TO263-5L packages.
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 al ways be higher tha n the Vout pi n in ord er to regu late the
device. A minimum of 100uF capacitor must be connected from this pin to ground to
insure stability.
Vout O
The output of the regulator. A minimum of 100uF capacitor must be conn ected from this
pin to ground to insure stability.
Block Diagram
THERMAL
SHUTDOWN
Vout
Adj
1.25V +
CURRENT
LIMIT
Vin
+-
+
+
-
Vsense
Vctrl
Pin Descriptions
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 3 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
(1) Adjustable Regulator
Tab is Vout
Vout
Vsense
Adj
Vctrl
Vin
470µF
3.3V 5V
470µF
470µF
2.5V/ 4A
121
121
R1
R2
Ω
Ω
)
1
R2
R
1(
REF
V
OUT
V:Note +×=
(2) 3.3V to 2.5V Fixed Mode Regulator
Tab is Vout
Vout
Vsense
GND
Vctrl
Vin
470µF
3.3V 5V
470µF
470µF
2.5V/ 4A
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 Range -65 to +150 oC
TOP Operation Junction Temperature Range 0 to +125 oC
Typical Application Circuit
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 4 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Electrical Characteristics (Under Operating Conditions)
Unless otherwise specified, these specifications apply over, Cin = 1uF, C out = 10uF, and Tj = 0 to 150oC. Typical value refer to TA = 25oC.
Vout = Vsense
Sym. Parameter Test Condition Min Typ. Max Unit
VREF Reference Voltage AP1184-Adj Io =10mA, TA = 25oC, (Vin-Vout) = 0.7V,
Vctrl = VIN+1V 1.225 1.250 1.275 V
Line Regulation AP1184-XXX
IO = 10mA, VOUT+0.7V<VIN<12V, TA = 25oC
Vctrl = VIN+1V 0.2 %
AP1184-1.5 IOUT = 10mA, TA = 25oC, 2.2VVIN12V
Vctrl = VIN+1V 1.470 1.500 1.530 V
AP1184-1.8 IOUT = 10mA, TA = 25oC, 2.5VVIN12V
Vctrl = VIN+1V 1.764 1.800 1.836 V
AP1184-2.5 IOUT = 10mA, TA = 25oC, 3.2VVIN12V
Vctrl = VIN+1V 2.450 2.500 2.550 V
AP1184-3.3 IOUT = 10mA, TA = 25oC, 4.0VVIN12V
Vctrl = VIN+1V 3.235 3.300 3.365 V
Vout Output Voltage
AP1184-5.0 IOUT = 10mA, TA = 25oC, 5.7VVIN12V
Vctrl = VIN+1V 4.900 5.000 5.100 V
AP1184-Adj 0mA<Io<4A, TA= 25oC
(VIN - VOUT) =2V ,Vctrl = VIN + 1V 1 %
AP1184-1.5 VIN = 3V, 0mA<Io<4A, TA = 25oC
Vctrl = 4V 12 15 mV
AP1184-1.8 VIN = 3.3V, 0mA<Io<4A, TA = 25oC
Vctrl = 4.3V 15 18 mV
AP1184-2.5 VIN = 4V, 0mA<Io<4A, TA = 25oC
Vctrl = 5V 20 25 mV
AP1184-3.3 VIN = 5V, 0mA<Io<4A, TA = 25oC
Vctrl = 6V 26 33 mV
Load
Regulation
AP1184-5.0 VIN = 8V, 0mA<Io<4A, TA = 25oC
Vctrl = 9V 40 50 mV
Dropout Voltage
(Vctrl –Vout)
Vadj = 0V for all conditions below.
Vin = 2.05V, Io = 1.5A
Vin = 2.05V, Io = 3A
Vin = 2.05V, Io = 4A
1.10
1.15
1.18
1.25
V
Dropout Voltage
(Vin – Vout)
Vadj = 0V for all conditions below.
Vctrl = 2.75V, Io = 1.5A
Vctrl = 2.75V, Io = 3A
Vctrl =2.75V, Io =4A
0.26
0.50
0.70
0.38
0.60
0.85
V
Current Limit Vctrl = 2.75V, Vin = 2.05V, ΔVo = 100mV, Vadj = 0V 4.2 A
Minimum Load
Current Vctrl = 5V, Vin = 3.3V, Vadj = 0V 5 10 mA
Thermal Regulation 30mS Pulse 0.01 0.02 %/W
Ripple Rejection Vctrl = 5V, Vin = 5V, Io = 4A, Vadj = 0V, Tj = 25, Vripple =1Vpp
at 120Hz 60 70 dB
Control Pin Current
Vadj = 0V for all conditions belo w.
Vctrl = 2.75V, Vin = 2.05V, Io = 1.5A
Vctrl = 2.75V, Vin = 2.05V, Io = 3A
Vctrl = 2.75V, Vin = 2.05V, Io = 4A
6
30
33
25
60
70
mA
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 5 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Electrical Characteristics (Continued)
Unless otherwise specified, these specifications apply over, Cin = 1uF, C out = 10uF, and Tj = 0 to 150oC. Typical value refer to TA = 25oC.
Vout = Vsense.
Sym. Parameter Test Condition Min Typ. Max Unit
I adj Adjust Pin Current Vctrl = 2.75V, Vin = 2.05,Vadjj = 0 50 150 µA
θJA Thermal Resistance
Junction-to-Ambient TO263-5L: Control Circuitry/Power Transistor (Note 4)
TO220-5L: Control Circuitry/Power Transistor (Note 5) 61
31 OC/W
OC/W
θJC Thermal Resistance
Junction-to-Case TO263-5L: Control Circuitry/Power Transistor (Note 4)
TO220-5L: Control Circuitry/Power Transistor (Note 5) 7
5 OC/W
OC/W
Notes: 3. AP1184-ADJ incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the allowable
maximum junction temperature.
4. Test conditions for TO263-5L : Devise mounted on 2oz copper, minimum recommended pad layout , FR-4 PCB.
5. Test conditions for TO220-5L : with copper area of approximately 3in2 , 1oz.
Package Max Pd. Remarks
TO263-5L/TO220-5L 2.4W~4.4W With heat sink or amount of copper board needed.
Functional Descriptions
Introduction
The AP1184 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 AP1184 ideal for applications where dual inputs are available such as a comput er
motherboard with an ATX style power suppl y 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 AP1184 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 AP1184 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 AP1184-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:
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 6 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Functional Descriptions (Continued)
Vout = Vref (1+R2/R1) + Iadj * R2 where : Vref = 1.25V & Iadj=50uA Typically
AP1184-ADJ
Vin
Vctrl Adj
Vout
Vsense
R1+
R2+
Vref
Iadj=50uA
The AP1184-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 cur rent r equire ment o f t he AP1184-ADJ is 10mA, R1 is t ypically 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 output voltage and should be considered when very precise output voltage setting is required.
Load Regulation
Since the AP1184 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 dro ps due to parasitic resistance such as PCB traces bet ween the regulator a nd
the load are compensated for using remote sensing. Figure following shows a typical application of the AP1184-ADJ with remote sensing.
AP1184-ADJ
Vin
Vctrl
Vin
Vctrl
Vout
Vsense
Adj R1
R2
R
L
Stability
The AP1184-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 t ypical ESR in the range of 50 to 100mΩ
and an output capacitance of 100uF to 1000uF. Fortunately as the capacitance increases, the ESR decreases resulting in a fixed RC
time constant. The AP1184-XXX takes advantage of the phenome n a in making the o verall regulator loop stable. For most applications a
minimum of 100uF aluminum electrolytic capacitor insures both stability and good transient response.
Thermal Design
The AP1184-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 150oC, it is
recommended that the selected heat sink be chosen such that du ring 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.
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 7 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Functional Descriptions (Continued)
Assuming, the following conditions:
Vout = 2.5V
Vin = 3.3V
Vctrl = 5V
Iout = 2A 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 θJA (oC/W) Max Pd (TA = 25oC) Max Pd (TA = 45oC)
TO263-5L Pad Size-1.4”X1.4” 25-45 2.4W-4.4W 2.0W-3.6W
Notes: 6. Above table is based on the maximum junction temperature of 135oC.
As shown in the above table, any of the two packages will do the job.
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 8 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Performance Characteristics
Output Current (A)
V
control
Dropout Voltage vs Output Current
Vcontrol Dropout Voltage (mV)
800
900
1000
1100
1200
Vpower = 2.05 V
Tj = 20
o
C
Tj = 120
o
C
00.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Output Current (A)
V
power
Dropout Voltage vs Output Current
0
Vpower Dropout Voltage (mV)
00.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800 Vcontrol = 2.75 V
Tj = 120
o
C
Tj = 20
o
C
Junction Temperature (
o
C)
Reference Voltage vs Junction Temperature
1. 247
1. 248
1. 249
1. 250
Reference Voltage (V)
1. 251
1. 252
1. 253
020 40 60 80 100 120 Output Current (A)
Load Regulation vs Output Current
Load Regulation (%)
0
0. 02
0. 04
0. 06
0. 08
0. 10
0. 12
0. 14
0. 15
Tj = 20
o
C
Tj = 120
o
C
00.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 9 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Performance Characteristic (Continued)
VCONTROL = 5.0V
VPOWER = 3.3V
VOUT = 2.5V
CCONTROL=10uF
CPOWER = 100uF
CADJ = 0.1uF
COUT = 470uF
ILOAD
10mA to 4A
Transient Response
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 10 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Marking Information
(1) TO263-5L
1184-XX
1184-XX: Voltage
1184-15 : 1.5V
1184-18 : 1.8V
1184-25 : 2.5V
1184-33 : 3.3V
Logo
ID code
Year :
( Top View )
"08" = 2008
"07" = 2007
YY WW X X
Xth week : 01~52
~
L : Lead Free
1184-50 : 5.0V
1184: Adj
(2) TO220-5L
1184-XX
1184-XX: Voltage
1184-15: 1.5V
1184-18: 1.8V
1184-50: 5.0V
Logo
ID code
Year: "08" = 2008
"07" = 2007
YY WW X XXth week: 01~52
~
L : Lead Free Package
( Top view )
1184-33: 3.3V
1184-25: 2.5V
1184: Adj
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 11 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
Package Information (All Dimensions in mm)
(1) Package Type: TO263-5L
(2) Package Type: TO220-5L
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
AP1184 Rev. 5 12 of 12 SEPTEMBER 2008
www.diodes.com © Diodes Incorporated
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