AP1086
1.5A LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Description
AP1086 is a low dropout positive adjustable or fixed-mode
regulator with 1.5A 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. AP1086 is also well suited
for other applications such as VGA cards. AP1086 is
guaranteed to have lower than 1.4V dropout at full load
current making it ideal to provide well-regulated outputs of
1.25V to 5.0V with 4.7 to 12V input supply by different output
voltage.
Pin Assignments
(Top View)
3
2
1
Tab is V
OUT
V
IN
V
OUT
Adj (GND)
TO252-3L
(Top View)
3
2
V
IN
V
OUT
Adj (GND)
Features
•
•
•
•
•
•
•
•
3-Terminal Adjustable or Fixed 1.5V, 1.8V, 2.5V,3.3V,
5.0V
1.4V Maximum Dropout at Full Load Current
Fast Transient Response
Built-in Thermal Shutdown
Output Current Limiting
Lead Free Packages: TO252-3L, TO263-3L, TO220-3L
TO252-3L, TO263-3L, and TO220-3L: Available in
“Green” Molding Compound (No Br, Sb)
Lead Free Finish/ RoHS Compliant (Note 1)
1
Tab is V
OUT
TO263-3L
(Top View)
3
2
1
Tab is V
OUT
V
IN
V
OUT
Adj (GND)
TO220-3L
Notes:
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
Typical Application Circuit
5V to 3.3V Fixed Mode Regulator
5V
C1
100uF
Vin
Vout
GND
Tab is Vout
3.3V/1.5A
C2
100uF
Vin
Vout
Adj
Tab is Vout
R1
121
Ω
R2
121
Ω
5V
C1
100uF
Adjustable Regulator
V
OUT
=V
ref
×
(1+R2/R1)
2.5V/1.5A
C2
100uF
Note:
V
o
=
V
RE
∗
F
( R
2
+
)
1 R
1
June 2010
© Diodes Incorporated
AP1086
Document number: DS31028 Rev. 6 - 2
1 of 10
www.diodes.com
AP1086
1.5A LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Pin Descriptions
Pin Name
Adj (GND)
V
OUT
O
I/O
Pin #
1
2
Description
Adjustable (Ground only for fixed mode)
The output of the regulator. A minimum of 10uF capacitor must be connected
from this pin to ground to insure stability.
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 V
OUT
in order for the device to regulate properly.
V
IN
I
3
Functional Block Diagram
V
IN
3
2
V
OUT
+
+
-
CURRENT
LIMIT
+
Thermal
Shutdown
1
Adj
-
1.25V
+
Absolute Maximum Ratings
Symbol
V
IN
T
ST
T
MJ
Parameter
DC Supply Voltage
Storage Temperature
Maximum Junction Temperature
Rating
-0.3 to 12
-65 to +150
150
Unit
V
o
C
o
C
Recommended Operating Conditions
Symbol
Top
Parameter
Operating Junction Temperature Range
Min
0
Max
125
Unit
o
C
AP1086
Document number: DS31028 Rev. 6 - 2
2 of 10
www.diodes.com
June 2010
© Diodes Incorporated
AP1086
1.5A LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Electrical Characteristics
(Under Operating Conditions)
Parameter
Reference Voltage
AP1086-Adj
AP1086-1.5
AP1086-1.8
Output Voltage
AP1086-2.5
AP1086-3.3
AP1086-5.0
Line Regulation
AP1086-XXX
AP1086-Adj
AP1086-1.5
AP1086-1.8
Load Regulation
AP1086-2.5
AP1086-3.3
AP1086-5.0
Dropout Voltage
(V
IN
-V
OUT
)
Current Limit
Minimum Load
Current (Note 4)
Thermal Regulation
Ripple Rejection
AP1086-Adj/-2.5/
-3.3/-3.6/-5.0
AP1086-Adj/-2.5/
-3.3/-3.6/-5.0
AP1086-XXX
Conditions
T
A
= 25
ο
C, (V
IN
-V
OUT
)= 1.5V,I
O
= 10mA
I
OUT
= 10mA, T
A
= 25
ο
C, 3V≦V
IN
≦12V
I
OUT
= 10mA, T
A
= 25
ο
C, 3.3V≦V
IN
≦12V
I
OUT
= 10mA, T
A
= 25 C, 4V≦V
IN
≦12V
I
OUT
= 10mA, T
A
= 25
ο
C, 4.8V≦V
IN
≦12V
I
OUT
= 10mA, T
A
= 25
ο
C, 6.5V≦V
IN
≦12V
I
O
= 10mA, V
OUT
+1.5V<V
IN
<12V
V
IN
= 3.3V, 0mA<Io<1.5A, T
A
= 25 C
(Note 2, 3)
V
IN
= 3V, 0mA<Io<1.5A, T
A
= 25
ο
C
(Note 2, 3)
V
IN
= 3.3V, 0mA<Io<1.5A, T
A
= 25
ο
C
(Note 2, 3)
V
IN
= 4V, 0mA<Io<1.5A, T
A
= 25
ο
C
(Note 2, 3)
V
IN
= 5V, 0≦I
OUT
≦1.5A,
T
A
= 25
ο
C,
T
J
= 25
o
C (Note 2, 3)
V
IN
= 8V, 0≦I
OUT
≦1.5A,
T
A
= 25
ο
C,
T
J
= 25
o
C (Note 2, 3)
I
OUT
= 1.5A,
ΔV
OUT
= 1%V
OUT
(V
IN
-V
OUT
) = 5V
o
o
0 C≦T
J
≦125
C
ο
ο
Min
1.225
1.470
1.764
2.450
3.235
4.900
-
-
-
-
-
-
-
-
1. 6
-
-
Typ.
1.250
1.500
1.800
2.500
3.300
5.000
-
-
12
15
20
26
40
1.3
-
5
0.008
60
0.003
0.5
101
83
86
15
0.65/2.7
0.65/2.7
Max
1.275
1.530
1.836
2.550
3.365
5.100
0.2
1
15
18
25
33
50
1.4
-
10
0.04
70
-
-
-
Unit
V
V
V
V
V
%
%
mV
mV
mV
mV
mV
V
A
mA
%/W
dB
%
%
o
T
A
= 25
ο
C, 30ms pulse
f = 120Hz,C
OUT
= 25uF Tantalum, I
OUT
= 1.5A
AP1086-XXX
I
O
= 10mA
TO252-3L
TO263-3L
TO220-3L
TO252-3L: Control Circuitry/Power Transistor
TO263-3L: Control Circuitry/Power Transistor
TO220-3L: Control Circuitry/Power Transistor
V
IN
= V
OUT
+3V
-
-
-
-
RMS Noise (% of V
OUT
)
Temperature Stability
θ
JA
Thermal Resistance
Junction-to-Ambient
(No heat sink; No air flow)
θ
JC
Thermal Resistance
Junction-to-Case
Notes:
10Hz
≤
f
≤
10KHz
C/W
-
-
o
C/W
2. 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.
3. Line and load regulation are guaranteed up to the maximum power dissipation of 15W. Power dissipation is determined by the difference in input and
output and the output current. Guaranteed maximum power dissipation will not be available over the full input/output range.
4. Quiescent current is defined as the minimum output current required in maintaining regulation. At 12V input/output differential the device is
guaranteed to regulate if the output current is greater than 10mA.
AP1086
Document number: DS31028 Rev. 6 - 2
3 of 10
www.diodes.com
June 2010
© Diodes Incorporated
AP1086
1.5A LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Functional Description
Introduction
The AP1086 adjustable or fixed-mode Low Dropout (LDO) regulator is a 3 terminal device which can easily be
programmed by internal mask change to any voltages within the range of 1.25V to V
IN
-1.4V. The AP1086 only
needs 1.4V differential between V
IN
and V
OUT
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
1.5A load step.
The AP1086 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.
Load Regulation
Since the AP1086 is only a 3 terminal device, it is not possible to provide true remote sensing of the output
voltage at the load. But it can supply good load regulation by internal feedback bypass the external loss such as
adjustable mode.
Stability
The AP1086 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.
Thermal Design
The AP1086 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 V
OUT
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 V
OUT
pin to the output capacitors to prevent
any high frequency oscillation that may result due to excessive trace inductance.
AP1086
Document number: DS31028 Rev. 6 - 2
4 of 10
www.diodes.com
June 2010
© Diodes Incorporated
AP1086
1.5A LOW DROPOUT POSITIVE ADJUSTABLE OR
FIXED-MODE REGULATOR
Typical Performance Characteristics
2. 0
1. 8
0.20
Output Voltage Deviation (%)
1. 6
0
I load=1.5A
Dropout Voltage (V)
1. 4
1. 2
1. 0
0. 8
0. 6
0. 4
0. 2
0
0
0.25
0.5
0.75
1.0
1.25
1.5
Tj = 125 C
o
Tj = 25
o
C
-0.20
-0.40
-0.80
-1
-25
0
Dropout Voltage vs Output Current
2
1.5
0.8
1
Output Current (A)
Temperature (
o
C)
25
50
75
100
125
Load Regulation vs Temperature
Output Voltage Change (%)
1
0. 5
0
-0.5
-1
-1.5
-2
-50
-25
0
25
50
75
100
125
150
Output Voltage Deviation (%)
0.6
0.4
0.2
0
Percent Change in Output Voltage vs Temperature
Output Voltage Deviation (mV) Input Voltage (V)
Load Current (A) Output Voltage Deviation (mV)
7.5
6.5
5.5
40
20
0
-20
-40
Cin=1uF
Cout=10uF Tantalum
30
20
10
0
-10
-20
2
1
0
-1
0
10
20
Temperature ( C)
o
2
4
6
8
10
12
Line Regulation
Cin=1uF
Cout=10uF Tantalum
Preload=100mA
Input Voltage (V)
0
20
40
60
80
100 120 140 160 180 200
TIME (us)
30
40
50
60
70
80
90
100
TIME (us)
Line Transient Response
Load Transient Response
AP1086
Document number: DS31028 Rev. 6 - 2
5 of 10
www.diodes.com
June 2010
© Diodes Incorporated
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