4A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
APE1184
General Description
APE1184 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.
Feature
0.7V maximum dropout voltage at 4A load current
•
Built-in Thermal shutdown
•
Output current limiting
•
Adjustable or fixed output voltage
1.2V,
1.5V, 1.8V, 2.5V, 3.3V, 5.0V
•
Fast transient response
•
Good noise rejection
•
Packages:
TO252-5L,
TO220-5L and TO263-5L
RoHS Compliant
•
Ordering Information
APE1184
X - XX
Low Dropout Regulator
Package
H:TO252-5L
S:TO263-5L
P:TO220-5L
Vout
Blank : Adj
12 = 1.2V
15 = 1.5V
18 = 1.8V
25 = 2.5V
33 = 3.3V
50 = 5.0V
Typical Application
5V
10uF
3.3V
470uF
Vctr1
Vin
V
OUT
Vsense
470uF
2.5V/4A
GND
This datasheet contains new product information. Advanced Power Electronics 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.
200730076-1/7
Advanced Power
Electronics Corp.
4A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
APE1184
Block Diagram
Vin
Vctrl
+
+
CURRENT
LIMIT
THERMAL
SHUTDOWN
-
1.25V
(1.2V)
+
-
Adj
+
Vout
Vsense
Pin Configuration
FRONT VIEW
5
4
3
2
1
Tab is Vout
Vin
Vctrl
Vout
Adj(GND)
Vsense
FRONT VIEW
5
Vin
4
Vctrl
3
Vout
2
Adj(GND)
1
Vsense
FRONT VIEW
5
4
3
2
1
Tab is Vout
Vin
Vctrl
Vout
Adj(GND)
Vsense
Metal
Tab
GND
Tab is Vout
(APE1184S)
( APE1184H )
(APE1184P)
Pin Descriptions
Name
Adj
(GND)
Vsense
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 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.
The output of the regulator. A minimum of 100uF capacitor must be connected from
this pin to ground to insure stability.
I
Vin
I
Vctrl
I
Vout
O
2/7
Advanced Power
Electronics Corp.
4A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
APE1184
Absolute Maximum Ratings
Symbol
V
IN
V
ctrl
P
D
T
ST
T
OP
Input Voltage
Control Input voltage
Power dissipation
Storage temperature Range
Operation Junction Temperature Range
Parameter
Rating
16
18
Internally limited
-65 to +150
0 to +150
o
o
Unit
V
V
C
C
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
APE1184-Adj
Test Condition
Io=10mA, Tj=25 C, (Vin-Vout)=0.7V,
V
ctrl
=V
IN
+1V
o
I =10mA, V
OUT
+0.7V<V
IN
<12V, T
J
=25 C
APE1184-XX
O
V
ctrl
=V
IN
+1V
I
OUT
= 10mA, T
J
= 25
o
C, 2.2V≦V
IN
≦12V
APE1184-1.2
V
ctrl
=V
IN
+1V
= 10mA, T
J
= 25
o
C, 2.2V≦V
IN
≦12V
I
APE1184-1.5
OUT
V
ctrl
=V
IN
+1V
I
OUT
= 10mA, T
J
= 25
o
C, 2.5V≦V
IN
≦12V
APE1184-1.8
V
ctrl
=V
IN
+1V
o
I
OUT
= 10mA, T
J
= 25 C, 3.2V≦V
IN
≦12V
APE1184-2.5
V
ctrl
=V
IN
+1V
I
OUT
= 10mA, T
J
= 25
o
C, 4.0V≦V
IN
≦12V
APE1184-3.3
V
ctrl
=V
IN
+1V
o
= 10mA, T
J
= 25 C, 5.7V≦V
IN
≦12V
I
APE1184-5.0
OUT
V
ctrl
=V
IN
+1V
0mA<Io<4A, T
J
=25
o
C
APE1184-Adj
(V
IN
- V
OUT
)=2V ,V
ctrl
=V
IN
+ 1V
o
V =3V, 0mA<Io<4A, T
J
=25 C
APE1184-1.2
IN
V
ctrl
=4V
o
V =3V, 0mA<Io<4A, T
J
=25 C
APE1184-1.5
IN
V
ctrl
=4V
o
V =3.3V, 0mA<Io<4A, T
J
=25 C
APE1184-1.8
IN
V
ctrl
=4.3V
o
V =4V, 0mA<Io<4A, T
J
=25 C
APE1184-2.5
IN
V
ctrl
=5V
V = 5V, 0mA<Io<4A, T
J
=25
o
C
APE1184-3.3
IN
V
ctrl
=6V
V
IN
= 8V, 0mA<Io<4A, T
J
=25
o
C
APE1184-5.0
V
ctrl
=9V
Vadj=0V for all conditions below.
Vin=2.05V, Io=1.5A
Vin=2.05V, Io=3A
Vin=2.05V, Io=4A
Vadj=0V for all conditions below.
V
ctrl
=2.75V, Io=1.5A
V
ctrl
=2.75V, Io=3A
V
ctrl
=2.75V, Io=4A
V
ctrl
=2.75V, Vin=2.05V,∆Vo=100mV, Vadj=0V
V
ctrl
=5V, Vin=3.3V, Vadj=0V
o
Min. Typ.
1.225 1.250
Max. Unit
1.275
0.5
V
%
V
V
REF
Reference Voltage
Line Regulation
1.176 1.200
1.224
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
V
V
V
V
%
mV
V
out
Output Voltage
10
12
12
15
20
26
40
15
18
25
33
50
1.15
1.25
1.40
0.38
0.60
0.85
10
mV
mV
mV
mV
mV
V
Load
Regulation
Dropout Voltage
(Vctrl –Vout)
Dropout Voltage
(Vin -Vout)
Current Limit
Minimum Load
Current
1.25
0.26
0.50
0.70
4.2
5
V
A
mA
3/7
Advanced Power
Electronics Corp.
4A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
APE1184
Electrical Characteristics(Continued)
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
Test Condition
Min. Typ.
0.01
60
70
6
30
33
50
2.7
2.7
10
Max. Unit
0.02
%/W
dB
25
60
70
150
Iadj
θ
JC
Thermal Regulation 30mS Pulse
V
ctrl
=5V, Vin=5V, Io=4A, Vadj=0V, Tj=25, Vripple=1Vpp at
Ripple Rejection
120Hz
Vadj=0V for all conditions below.
V =2.75V, Vin=2.05V, Io=1.5A
Control Pin Current
ctrl
V
ctrl
=2.75V, Vin=2.05V, Io=3A
Vctrl=2.75V, Vin=2.05V, Io=4A
Adjust Pin Current Vctrl=2.75V, Vin=2.05,Vadj=0
TO-263: Control Circuitry/Power Transistor
Thermal Resistance
TO-220: Control Circuitry/Power Transistor
Junction-to-Case
TO-252:
Control Circuitry/Power Transistor
mA
µA
C/W
O
C/W
O
C/W
O
NOTE:
APE1184-ADJ incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the allowable
maximum junction temperature.
Functional Descriptions
Introduction
The APE1184 regulator is 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 APE1184 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 APE1184
can easily be programmed with the addition of two
external resistors to any voltages within the range
of 1.2V 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 APE1184 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 APE1184-ADJ can be programmed to any
voltages in the range of 1.2V to 15.5V with the
addition of R1 and R2 external resistors according
to the following formula:
4/7
Advanced Power
Electronics Corp.
4A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
APE1184
Functional Descriptions(Continued)
Vout = Vref (1+R2/R1) + Iadj * R2 where : Vref = 1.25V & Iadj=50uA Typically
Vin
Vout
APE1184-ADJ
Vsense
Vctrl
Adj
Vref
R1+
Iadj=50uA
R2+
The APE1184-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
APE1184-ADJ is 10mA, R1 is typically selected to be
a 121
Ω
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
Vout
output voltage and should be considered when very
precise output voltage setting is required.
Load Regulation
Since the APE1184 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 APE1184-ADJ with remote
sensing.
Vin
APE1184-ADJ
Vsense
Vctrl
Vctrl
Adj
R1
R2
R
L
Stability
The APE1184-XX 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
Ω
and an output capacitance of
100uF to 1000uF. Fortunately as the capacitance
increases, the ESR decreases resulting in a fixed
RC time constant. The APE1184-XX 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.
