AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Features
•
•
•
•
•
•
•
•
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 Compliant for Lead Free
products (Note 1)
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.
Ordering Information
AP1184 XX - XX X X
Package
K5 : TO263-5L
T5 : TO220-5L
Vout
Blank : Adj
15 = 1.5V
18 = 1.8V
25 = 2.5V
33 = 3.3V
50 = 5.0V
Lead Free
L : Lead Free
Packing
-U : Tube
-13 : Taping
Device
Lead-free
Package Packaging
Code
(Note 2)
K5
T5
TO263-5L
TO220-5L
Tube/Bulk
Part Number
Quantity
Suffix
50
50
-U
-U
13” Tape and Reel
Part Number
Quantity
Suffix
800/Tape & Reel
NA
-13
NA
Lead-free
AP1184K5
AP1184T5
Notes:
1. RoHS revision 13.2.2003. Glass and high temperature solder exemptions applied, see
EU Directive Annex Notes 5 and 7.
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 Rev. 4
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Diodes Incorporated
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Pin Assignments
FRONT VIEW
5
4
3
2
1
Tab is Vout
Vin
Vctrl
Vout
Adj(GND)
Vsense
FRONT VIEW
5
4
3
2
1
Tab is Vout
Vin
Vctrl
Vout
Adj(GND)
Vsense
TO263-L
TO220-5L
Pin Descriptions
Pin Numbers with standard type are for TO220-5L, TO263-5L packages.
Name
Adj
(GND)
Vsense
I/O
I
Vin
I
Vctrl
NC
Vout
I
O
Description
A resistor divider from this pin to the Vout pin and ground sets the output voltage. (GND
only for fixed mode)
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.
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.
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 be higher than the Vout pin in order to regulate the
device. A minimum of 100uF capacitor must be connected from this pin to ground to
insure stability.
No connection
The output of the regulator. A minimum of 100uF capacitor must be connected from this
pin to ground to insure stability.
AP1184 Rev. 4
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Diodes Incorporated
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Block Diagram
Vin
Vctrl
Vout
Vsense
+
+
CURRENT
LIMIT
+
THERMAL
SHUTDOWN
-
Adj
-
1.25V
+
Typical Application Circuit
3.3V
+
470uF
G ND
Vsense
5V
+
470uF
Vin
Vctrl
.
NC
Vout
2.5V/4A
Vout
+
Vin
470uF
AP1184-2.5V
Absolute Maximum Ratings
Symbol
V
IN
V
ctrl
P
D
T
ST
T
OP
Parameter
Input Voltage
Control Input voltage
Power dissipation
Storage temperature Range
Operation Junction Temperature Range
Rating
16
18
Internally limited
-65 to +150
0 to +125
Unit
V
V
o
o
C
C
AP1184 Rev. 4
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Diodes Incorporated
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Electrical Characteristics
V
out
= V
sense
( Under Operating Conditions )
o
o
Unless otherwise specified, these specifications apply over, C
in
= 1uF, C
out
= 10uF, and T
j
= 0 to 150 C. Typical value refer to T
A
= 25 C.
Sym.
Parameter
AP1184-Adj
Test Condition
I
o
=10mA, T
A
= 25 C, (V
in
-V
out
) = 0.7V,
V
ctrl
= V
IN
+1V
o
I
O
= 10mA, V
OUT
+0.7V<V
IN
<12V, T
A
= 25 C
AP1184-XXX
V
ctrl
= V
IN
+1V
o
I
OUT
= 10mA, T
A
= 25 C, 2.2V V
IN
12V
AP1184-1.5
V
ctrl
= V
IN
+1V
o
I
OUT
= 10mA, T
A
= 25 C, 2.5V V
IN
12V
AP1184-1.8
V
ctrl
= V
IN
+1V
o
I
OUT
= 10mA, T
A
= 25 C, 3.2V V
IN
12V
AP1184-2.5
V
ctrl
= V
IN
+1V
o
I
OUT
= 10mA, T
A
= 25 C, 4.0V V
IN
12V
AP1184-3.3
V
ctrl
= V
IN
+1V
o
I
OUT
= 10mA, T
A
= 25 C, 5.7V V
IN
12V
AP1184-5.0
V
ctrl
= V
IN
+1V
o
0mA<Io<4A, T
A
= 25 C
AP1184-Adj
(V
IN
- V
OUT
) =2V ,V
ctrl
= V
IN
+ 1V
o
V
IN
= 3V, 0mA<Io<4A, T
A
= 25 C
AP1184-1.5
V
ctrl
= 4V
o
V
IN
= 3.3V, 0mA<Io<4A, T
A
= 25 C
AP1184-1.8
V
ctrl
= 4.3V
o
V
IN
= 4V, 0mA<Io<4A, T
A
= 25 C
AP1184-2.5
V
ctrl
= 5V
o
V
IN
= 5V, 0mA<Io<4A, T
A
= 25 C
AP1184-3.3
V
ctrl
= 6V
o
V
IN
= 8V, 0mA<Io<4A, T
A
= 25 C
AP1184-5.0
V
ctrl
= 9V
V
adj
= 0V for all conditions below.
V
in
= 2.05V, I
o
= 1.5A
V
in
= 2.05V, I
o
= 3A
V
in
= 2.05V, I
o
= 4A
V
adj
= 0V for all conditions below.
V
ctrl
= 2.75V, I
o
= 1.5A
V
ctrl
= 2.75V, I
o
= 3A
V
ctrl
=2.75V, I
o
=4A
V
ctrl
= 2.75V, V
in
= 2.05V,
ΔVo
= 100mV, V
adj
= 0V
o
Min. Typ.
1.225 1.250
Max. Unit
1.275
0.2
V
%
V
V
V
V
V
%
mV
mV
mV
mV
mV
V
REF
Reference Voltage
Line Regulation
1.470 1.500
1.764 1.800
2.450 2.500
3.235 3.300
4.900 5.000
1.530
1.836
2.550
3.365
5.100
1
V
out
Output Voltage
12
15
20
26
40
15
18
25
33
50
1.15
1.18
1.25
0.38
0.60
0.85
10
0.02
Load
Regulation
Dropout Voltage
(V
ctrl
–V
out
)
V
1.10
0.26
0.50
0.70
4.2
5
0.01
60
70
6
30
33
Dropout Voltage
(V
in
– V
out
)
V
A
mA
%/W
dB
Current Limit
Minimum Load
V
ctrl
= 5V, V
in
= 3.3V, V
adj
= 0V
Current
Thermal Regulation 30mS Pulse
Vctrl = 5V, Vin = 5V, Io = 4A, Vadj = 0V, Tj = 25, Vripple =1Vpp
Ripple Rejection
at 120Hz
Vadj = 0V for all conditions below.
Vctrl = 2.75V, Vin = 2.05V, Io = 1.5A
Control Pin Current
Vctrl = 2.75V, Vin = 2.05V, Io = 3A
Vctrl = 2.75V, Vin = 2.05V, Io = 4A
25
60
70
mA
AP1184 Rev. 4
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Diodes Incorporated
AP1184
4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Electrical Characteristics
V
ou
t
= V
sense
.
( Continued )
o
o
Unless otherwise specified, these specifications apply over, C
in
= 1uF, C
out
= 10uF, and T
j
= 0 to 150 C. Typical value refer to T
A
= 25 C.
Sym.
I
adj
Parameter
Adjust Pin Current
Test Condition
V
ctrl
= 2.75V, V
in
= 2.05,V
adjj
= 0
TO263-5L: Control Circuitry/Power Transistor (Note 4)
TO220-5L: Control Circuitry/Power Transistor (Note 5)
TO263-5L: Control Circuitry/Power Transistor (Note 4)
TO220-5L: Control Circuitry/Power Transistor (Note 5)
Min. Typ.
50
61
31
7
5
Max. Unit
150
O
O
O
O
µA
C/W
C/W
C/W
C/W
θ
JA
Thermal Resistance
Junction-to-Ambient
θ
JC
Thermal Resistance
Junction-to-Case
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 3in
2
, 1oz.
Package
TO263-5L/TO220-5L
Max Pd.
2.4W~4.4W
Remarks
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
V
in
pin. This flexibility makes the AP1184 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 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 Rev. 4
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Diodes Incorporated
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