Diodes AP1122 User Manual
AP1122
1A LOW DROPOUT POSITIVE REGULATOR
Description
AP1122 is a low dropout positive fixed-mode regulator with
1A 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 1.2V logic supply. AP1122 is also well suited for other
applications such as VGA cards. AP1122 is guaranteed to
have lower than 1.3V dropout at full load current making it
ideal to provide well-regulated outputs of 1.2 output voltage
with 2.5V input voltage supply.
Applications
• PC peripheral
• Communication
Features
• 1.3V maximum dropout at full load current
• Fixed 1.2V± 2% output voltage
• Fast transient response
• Output current limiting
• Built-in thermal shutdown
• Good noise rejection
• Packages: SOT223-3L, TO252-3L, SOT89-3L, TO263-3L
and TO220-3L
• SOT89-3L, SOT223-3L and TO252-3L: Available in
“Green” Molding Compound (No Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
Pin Assignments
(Top View)
Tab is V
SOT223-3L
(Top View)
TO252-3L/ TO263-3L
(Top View)
Tab is V
SOT89-3L
( Top View)
3
2
1
OUT
3
2
1
Tab is V
3
2
1
OUT
OUT
V
V
GND
V
IN
V
OUT
GND
IN
OUT
V
IN
V
OUT
GND
3
2
1
Tab is V
TO220-3L
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
AP1122
Document number: DS31012 Rev. 9 - 2
http://www.diodes.com/products/lead_free.html.
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OUT
V
IN
V
OUT
GND
May 2010
© Diodes Incorporated
Typical Application Circuit
2.5V
AP1122
1A LOW DROPOUT POSITIVE REGULATOR
C1
100uF
V
IN
V
OUT
1.2V/1A
C2
100uF
Tab is V
GND
OUT
Pin Descriptions
Pin Name I/O Pin # Description
GND I 1 Ground Pin
V
O 2
OUT
The output of the regulator. A minimum of 10uF capacitor (0.15Ω ≤ ESR ≤ 20Ω)
must be connected from this pin to ground to insure stability.
The input pin of regulator. Typically a large storage capacitor is connected from
VIN I 3
this pin to ground to insure that the input voltage does not sag below the
minimum dropout voltage during the load transient response.
Functional Block Diagram
V
3
IN
2 V
OUT
Thermal
Shutdown
AP1122
Document number: DS31012 Rev. 9 - 2
+
+
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CURRENT
LIMIT
+
1.2V
+
GND
1
May 2010
© Diodes Incorporated
AP1122
1A LOW DROPOUT POSITIVE REGULATOR
Absolute Maximum Ratings
Symbol Parameter Rating Unit
VIN DC Supply Voltage -0.3 to 12 V
TST Storage Temperature -65 to +150
TMJ Maximum Junction Temperature 150
Recommended Operating Conditions
Symbol Parameter Min Max Unit
I
Output Current - 1.0 A
OUT
TOP Operating Junction Temperature Range 0 125
Electrical Characteristics (Under Operating Conditions)
Parameter Test Conditions Min Typ. Max Unit
Output Voltage
Line Regulation
Load Regulation VIN=2.5V~12V, 10mA<Io<1A, TA=25oC (Note 2, 3) 1 %
Dropout Voltage
(VIN-V
OUT
)
Current Limit (VIN-V
Minimum Load Current
(Note 4)
Thermal Regulation TA=25oC, 30ms pulse 0.008 0.04 %/W
Ripple Rejection F=120Hz,C
Temperature Stability IO=10mA 0.5 %
θ
Thermal Resistance
JA
Junction-to-Ambient
θ
Thermal Resistance
JC
Junction-to-Case
Notes: 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 between input and output differential 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.
5. Test conditions for SOT89-3L, TO252-3L, TO220-3L, and TO263-3L: Devices mounted on FR-4 substrate, single sided PC
board, 2oz copper, with minimum recommended pad layout, no air flow.
6. Test condition for SOT223-3L: Device mounted on FR-4 substrate, single sided PC board, 2oz copper, with 5mmX5mm thermal
pad layout, no air flow.
2.5V≦VIN≦12V, IO=10mA, TA=25oC
2.5V≦VIN≦12V, IO=10mA, TA=25oC
I
= 1A ,ΔV
OUT
OUT
o
0
C≦TJ≦125oC
OUT
= 1%V
OUT
) = 5V 1. 1 A
=25uF Tantalum, I
OUT
=1A, VIN=V
OUT
+3V 60 70 dB
OUT
SOT89-3L: Control Circuitry/Power Transistor (Note 5)
SOT223-3L: Control Circuitry/Power Transistor (Note 6)
TO252-3L: Control Circuitry/Power Transistor (Note 5)
TO220-3L: Control Circuitry/Power Transistor (Note 5)
TO263-3L: Control Circuitry/Power Transistor (Note 5)
SOT89-3L: Control Circuitry/Power Transistor (Note 5)
SOT223-3L: Control Circuitry/Power Transistor (Note 6)
TO252-3L: Control Circuitry/Power Transistor (Note 5)
TO220-3L: Control Circuitry/Power Transistor (Note 5)
TO263-3L: Control Circuitry/Power Transistor (Note 5)
1.176 1.2 1.224 V
0.2 %
1.3 V
5 10 mA
182
107
73
78
60
42
16
12
3.5
3.5
AP1122
Document number: DS31012 Rev. 9 - 2
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o
C
o
C
o
C
o
C/W
o
© Diodes Incorporated
C/W
May 2010
Typical Performance Characteristics
AP1122
1A LOW DROPOUT POSITIVE REGULATOR
2. 0
1. 8
1. 6
1. 4
Dropout Voltage (V)
1. 2
1. 0
0. 8
0. 6
0. 4
0. 2
0
0
Tj = 25 oC
250
Output Current (mA)
500
Tj = 125 oC
Dropout Voltage vs Output Current
2
1.5
1
0. 5
0
-0.5
750
1000
0.20
-0.20
-0.40
-0.80
Output Voltage Deviation (%)
- 1
0
-25 0
I load=800mA
25 50 75 100 125
Temperature (oC)
Load Regulation vs Temperature
1
0.8
0.6
0.4
- 1
-1.5
Output Voltage Change (%)
- 2
-50 -25 0 25 50 75 100 125 150
Percent Change in Output Voltage vs Temperature
7.5
Cin=1uF
Cout=10uF Tantalum
6.5
5.5
40
20
0
-20
-40
0 20 40 60 80 100 120 140 160 180 200
Output Volta ge Deviation (mV) Input Voltage (V)
Temperature (oC)
TIME (us)
Line Transient Response
AP1122
Document number: DS31012 Rev. 9 - 2
0.2
Output Voltage Deviation (%)
0
24
30
20
10
0
-10
-20
Output Voltage Dev i a tion (mV)
2
1
0
-1
010
Load Current (A)
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Input Voltage (V)
Line Regulation
C in = 1uF
C out = 10 uF Tantalum
Preload = 100mA
20 30 40 50 60 70 80 90 100
TIME (us)
Load Transient Response
May 2010
© Diodes Incorporated
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