AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
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.1.0 Aug.27, 2004
1/10
Features
1.4V maximum dropout at full load current
Built-in thermal shutdown
Output current limiting
Adjustable output voltage or fixed 1.5V, 1.8V, 2.5V,
3.3V, 5.0V
Fast transient response
Good noise rejection
Package : TO252, TO263, TO220
Ordering Information
General Description
AP1084 is a low dropout positive adjustable or fixed-
mode regulator with minimum of 5.0A output current
capability. The product is specifically designed to
provide well-regulated supply for low voltage IC
applications such as high-speed bus termination and
low current 3.3V logic supply. AP1084 is also well
suited for other applications such as VGA cards.
AP1084 is guaranteed to have lower than 1.4V
dropout at full load current making it ideal to provide
well-regulated outputs of 1.25 to 3.3V with 4.7 to
12V input supply.
AP1084 X X X X
Low Dropout Regulator
Package
Vout
D : TO252-3L
K : TO263-3L
T : TO220-3L
Blank : Adj
15 = 1.5V
18 = 1.8V
25 = 2.5V
33 = 3.3V
50 = 5.0V
Packing
Blank : Tube
A : Taping
Lead Free
Blank : Normal
L : Lead Free Package
Typical Circuit
5.0V to 3.3V Fixed Mode Regulator
C2
100uF
5V
3.3V/5A
Tab is Vout
Vin
Vout
GND
C1
100uF
Adjustable Regulator
R1
R2
C2
100uF
5V
2.5V/5A
Tab is Vout
Vin
Vout
Adj
C1
100uF
121
121
)
1
2
REF
o
R
R
(1
V
V
+
=
Note:
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
2/8
Block Diagram
3
Thermal
Shutdown
1
2 Vout
Adj
1.25V
+
+
CURRENT
LIMIT
Vin
+
+
Connection Diagram
TO263
3
2
1
Vin
Vout
Adj (GND)
Tab is Vout
FRONT VIEW
TO252
3
2
1
Vin
Vout
Adj (GND)
Tab is Vout
FRONT VIEW
TO220
Tab is Vout
3
Vin
2
1
Vout
Adj (GND)
FRONT VIEW
Pin Descriptions
NAME
I/O
PIN #
FUNCTION
Adj (GND)
1
Adjustable (Ground only for fixed mode)
Vout O 2
The output of the regulator. A minimum of 10uF capacitor must be
connected from this pin to ground to insure stability.
Vin I
3
The input pin of 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 1.4V higher than Vout in order for the device to regulate
properly.
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
3/10
Absolute Maximum Ratings
Symbol
Parameter
Rating
Unit
Vin
DC Supply Voltage
-0.3 to 12
V
P
D
Power Dissipation
Internally Limited
T
ST
Storage Temperature
-65 to +150
oC
T
OP
Operating Junction Temperature Range
0 to +150
oC
Electrical Characteristics
(Under Operating Conditions)
SYM.
PARAMETER
CONDITIONS (Notes)
MIN
TYP
MAX
UNIT
V
REF
Reference
Voltage
Io=10mA,
Tj=25
o
C, (Vin-Vout)=1.5V
1.225
1.250 1.275
V
AP1084-XXX I
O
=10mA, V
OUT
+1.5V<V
IN
<12V, T
J
=25
o
C
0.2
%
AP1084-1.5
I
OUT
= 10mA, T
J
= 25
o
C, 3VV
IN
12V
1.470
1.500 1.530
V
AP1084-1.8
I
OUT
= 10mA, T
J
= 25
o
C, 3.3VV
IN
12V
1.764
1.800 1.836
V
AP1084-2.5
I
OUT
= 10mA, T
J
= 25
o
C, 4VV
IN
12V
2.450
2.500 2.550
V
AP1084-3.3
I
OUT
= 10mA, T
J
= 25
o
C, 4.8VV
IN
12V
3.235
3.300 3.365
V
Line
Regulation
AP1084-5.0
I
OUT
= 10mA, T
J
= 25
o
C, 6.5VV
IN
12V
4.900
5.000 5.100
V
AP1084-Adj
V
IN
=3.3V, 0mA<Io<5A, T
J
=25
o
C
(Note 1,2)
1
%
AP1084-1.5
V
IN
=3V, 0mA<Io<5A, T
J
=25
o
C
(Note 1,2)
12 15
mV
AP1084-1.8
V
IN
=3.3V, 0mA<Io<5A
T
J
=25
o
C (Note 1,2)
15 18
mV
AP1084-2.5
V
IN
=4V, 0mA<Io<5A
T
J
=25
o
C (Note 1,2)
20 25
mV
AP1084-3.3 V
IN
= 5V, 0mA<Io<5A , T
J
=25
o
C (Note 1,2)
26
33
mV
Load
Regulation
AP1084-5.0 V
IN
= 8V, 0mA<Io<5A, T
J
=25
o
C (Note 1,2)
40
50
mV
Vo
Dropout Voltage
Io=5.0A (
Vout = 1% Vout)
1.3
1.4 V
Current
Limit Vin-Vout=5V
5.1 A
Minimum Load
Current
5
10
mA
Temperature
Stability
Io=10mA
0.5 %
JA
Thermal Resistance
Junction-to-Ambient
(No heat sink ;No air
flow)
TO-252
TO-263
TO-220
98
91
83
O
C/W
JC
Thermal Resistance
Junction-to-Case
TO-252: Control Circuitry/Power Transistor
TO-263: Control Circuitry/Power Transistor
TO-220: Control Circuitry/Power Transistor
15
10
0.65/2.7
O
C/W
Note 1: See thermal regulation specifications for changes in output voltage due to heating effects. Line and load regulation are measured
at a constant junction temperature by low duty cycle pulse testing. Load regulation is measured at the output lead = 1/18" from the
package.
Note 2:Line and load regulation are guaranteed up to the maximum power dissipation of 15W. Power dissipation is determined by the
difference between input and output and the output current. Guaranteed maximum power dissipation will not be available over
the full input/output range.
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
4/10
Functional Description
Introduction
The AP1084 adjustable Low Dropout (LDO)
regulator is a 3 terminal device that can easily be
programmed with the addition of two external
resistors to any voltages within the range of 1.25 to
5V. The AP1084 only needs 1.4V differential
between Vin and Vout to maintain output regulation.
In addition, the output voltage tolerances are also
extremely tight and they include the transient
response as part of the specification. For example,
Intel VRE specification calls for a total of +/- 100mV
including initial tolerance, load regulation and 0 to
5.0A load step.
The AP1084 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 output capacitors.
Output Voltage Setting
The AP1084 can be programmed to any voltages in
the range of 1.25V to 5V with the addition of R1 and
R2 external resistors according to the following
formula:
Vout = Vref (1+ R2/R1) +Iadj *R2 , where Vref = 1.25 typically, Iadj = 55uA
typically R1&R2 as shown at below
AP1084
Vin
Vout
Vref
Adj
R1
R2
Iadj=55uA
The AP1084 keeps a constant 1.25V between the
output pin and the adjust pin. By placing a resistor
R1 across these two pins 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 which will be 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 AP1084 is 10mA, R1 is
typically selected to be 121 resistor so that it
automatically satisfies the minimum current
requirement. Notice that since Iadj is typically in the
range of 55uA it only adds a small error to the
output voltage and should only be considered when
a very precise output voltage setting is required. For
example, in a typical 3.3V application where
R1=121 and R2=200 the error due to Iadj is only
0.3% of the nominal set point.
Load Regulation
Since the AP1084 is only a 3 terminal device, it is
not possible to provide true remote sensing of the
output voltage at the load. The best load regulation
is achieved when the bottom side of R2 is
connected to the load and the top-side of R1
resistor is connected directly to the case or the Vout
pin of the regulator and not to the load. It is
important to note that for high current applications,
this can re-present a significant percentage of
the overall load regulation and one must keep the
path from the regulator to the load as short as
possible to minimize this effect.
Stability
The AP1084 requires the use of an output capacitor
as part of the frequency compensation in order to
make the regulator stable. For most applications a
minimum of 10uF aluminum electrolytic capacitor
insures both stability and good transient response.
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
5/10
Functional Description (Continued)
Thermal Design
The AP1084 incorporates an internal thermal
shutdown that protects the device when the junction
temperature exceeds the maximum allowable
junction temperature. Although this device can
operate with junction temperatures in the range of
150
o
C, it is recommended that the selected heat
sink be chosen such that during maximum
continuous load operation the junction temperature
is kept below the temperature.
Layout Consideration
The output capacitors must be located as close to
the Vout terminal of the device as possible. It is
recommended to use a section of a layer of the PC
board as a plane to connect the Vout pin to the
output capacitors to prevent any high frequency
oscillation that may result due to excessive trace
inductance.
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
6/10
Performance Characteristics
Temperature (
o
C)
Percent Change in Output Voltage vs Temperature
Output Voltage Change (%)
-50
-25
0
25
50
75
100
125
150
- 2
-1.5
- 1
-0.5
0
0. 5
1
1.5
2
Input Voltage (V)
Line Regulation
Output Voltage Deviation (%)
0
0.2
0.4
0.6
0.8
1
2
4
6
8
10
12
TIME (us)
Line Transient Response
Output Voltage Deviati
on (mV)
Input Voltage (V)
-40
-20
0
20
40
5.5
6.5
7.5
Cin=1uF
Cout=10uF Tantalum
0
20
40
60
80
100 120 140 160 180 200
TIME (us)
Load Transient Response
Load Current (A)
Output Voltage Deviation (mV)
0
10
20 30
40
50
60
70
80
90 100
0
2
4
6
-40
-20
0
20
40
60
Cin=1uF
Cout=10uF Tantalum
Preload=100mA
Output Current (A)
Dropout Voltage vs Output Current
Dropout Voltage (V)
0
0. 2
0. 4
0. 6
0. 8
1. 0
1. 2
1. 4
1. 6
1. 8
2. 0
0
1
2
3
4
Tj = 125
o
C
Tj = 25
o
C
5
Temperature (
o
C)
Load Regulation vs Temperature
Output Voltage Deviation (%)
-25
0
25
50
75
100
125
- 1
-0.80
-0.40
-0.20
0
0.20
I load=1.5A
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
7/10
Marking Information
Logo
Part Number
1084 for ADJ
84-VV : 15 for 1.5V
18 for 1.8V
25 for 2.5V
33 for 3.3V
50 for 5V
YY : Year
WW: Nth week
X : Internal code ( Optional)
( Top View)
84-VV
YYWWX X
Blank: normal
L: Lead Free Package
(TO252-3L)
Logo
Part Number
VV : 15 for 1.5V
18 for 1.8V
25 for 2.5V
33 for 3.3V
50 for 5V
Blank for ADJ
YY : Year
WW: Nth week
X : Internal code ( Optional)
( Top View)
1084-VV
YYWWX X
Blank: normal
L: Lead Free Package
(TO220-3L / TO263-3L)
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
8/10
Package Dimension
(1) TO263-3L
E
e
L2
b
b2
D
L3
L
A
C2
C
L1
1.3
3
15
.
7
10.9
9.
1
Land Pattern Recommendation (Unit: mm)
2.54
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min.
Nom.
Max.
Min.
Nom.
Max.
A 4.06 4.45 4.83 0.160 0.175 0.190
b 0.51 0.75 0.99 0.020 0.030 0.039
b2 1.14 1.27 1.40 0.045 0.050 0.055
C 0.38
TYP.
0.015
TYP.
C2 1.14 1.27 1.40 0.045 0.050 0.055
D 8.65 9.15 9.65 0.341 0.360 0.380
E 9.65 9.97 10.29 0.380 0.393 0.405
e 2.54
BSC.
0.100
BSC.
L 14.61 15.24 15.88 0.575 0.600 0.625
L1 2.28 2.54 2.80 0.090 0.100 0.110
L2 - 1.30
2.92 - 0.051
0.115
L3 1.27 1.52 1.78 0.050 0.060 0.070
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
9/10
(2) TO252-3L
b2
E
e
b
L2
e1
D
L1
H
A
C1
C
A1
SEATING PLANE
SE
E N
O
TE
2
L
5.
6
11
.
0
5.6
2.
0
2.25
Land Pattern Recommendation (Unit: mm)
7.
2
1.2
Notes:
1.
JEDEC Outline: TO-252 AB
2.
Mils suggested for positive contact at mounting.
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min.
Nom.
Max.
Min.
Nom.
Max.
A 2.18 2.29 2.39 0.086 0.090 0.094
A1 1.02 1.15 1.27 0.040 0.045 0.050
b 0.61
TYP.
0.024
TYP.
b2 5.20 5.35 5.50 0.205 0.211 0.217
C 0.46 0.52 0.58 0.018 0.020 0.023
C1 0.46 0.52 0.58 0.018 0.020 0.023
D 5.33 5.57 5.80 0.210 0.219 0.228
E 6.35 6.58 6.80 0.250 0.259 0.268
e 2.25
BSC.
0.089
BSC.
e1 4.50
BSC.
0.177
BSC.
H 9.00 9.70 10.40 0.354 0.382 0.409
L 0.51 - - 0.020 - -
L1 0.64 0.83 1.02 0.025 0.033 0.040
L2 1.52 1.78 2.03 0.060 0.070 0.080
AP1084
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
10/10
(3) TO220-3L
A
J1
F
C
SEATING PLANE
D
Q
E
L1
L
b
e
e1
b1
P
H1
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min.
Nom.
Max.
Min.
Nom.
Max.
A 3.55 4.20 4.85 0.140 0.165 0.191
b1 1.14 1.46 1.78 0.045 0.057 0.070
b 0.51 0.83 1.14 0.020 0.033 0.045
C 0.31 0.72 1.14 0.012 0.028 0.045
D 14.20 15.35 16.50 0.559 0.604 0.650
E 9.70 10.20 10.70 0.382 0.402 0.421
e 2.29 2.54 2.79 0.090 0.100 0.110
e1 4.83 5.08 5.33 0.190 0.200 0.210
F 0.51 0.95 1.40 0.020 0.037 0.055
H1 5.84 6.35 6.86 0.230 0.250 0.270
J1 2.03 2.48 2.92 0.080 0.098 0.115
L 12.72 13.72 14.72 0.501 0.540 0.580
L1 3.66 5.00 6.35 0.144 0.197 0.250
P 3.53 3.81 4.09 0.139 0.150 0.161
Q 2.54 2.98 3.43 0.100 0.117 0.135
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