Advanced
Monolithic
Systems

AMS1117
1A LOW DROPOUT VOLTAGE REGULATOR

RoHs Compliant
FEATURESAPPLICATIONS• Three Terminal Adjustable or Fixed Voltages*
1.5V, 1.8V, 2.5V, 2.85V, 3.3V and 5.0V
• Output Current of 1A• Operates Down to 1V Dropout• Line Regulation: 0.2% Max.
• Load Regulation: 0.4% Max.
• SOT-223, TO-252 and SO-8 package available• High Efficiency Linear Regulators• Post Regulators for Switching Supplies• 5V to 3.3V Linear Regulator• Battery Chargers• Active SCSI Terminators• Power Management for Notebook• Battery Powered Instrumentation

GENERAL DESCRIPTIONTheThe AMS1117 series of adjustable and fixed voltage regulators are designed to provide up to1A output current and to operate
down to 1V input-to-output differential. The dropout voltage of the device is guaranteed maximum 1.3V, decreasing at lower
load currents.
On-chip trimming adjusts the reference voltage to 1.5%. Current limit is set to minimize the stress under overload conditions
on both the regulator and power source circuitry.
The AMS1117 devices are pin compatible with other three-terminal SCSI regulators and are offered in the low profile surface
mount SOT-223 package, in the 8L SOIC package and in the TO-252 (DPAK) plastic package.

ORDERING INFORMATION:

PACKAGE TYPEOPERATING JUNCTION

TO-252
SOT-223
8L SOICAMS1117CD
AMS1117
AMS1117CS
AMS1117CD-1.5 AMS1117-1.5
AMS1117CS-1.5
AMS1117CD-1.8 AMS1117-1.8
AMS1117CS-1.8
AMS1117CD-2.5 AMS1117-2.5
AMS1117CS-2.5
AMS1117CD-2.85 AMS1117-2.85
AMS1117CS-2.85
AMS1117CD-3.3 AMS1117-3.3
AMS1117CS-3.3
AMS1117CD-5.0 AMS1117-5.0
AMS1117CS-5.0*For additional available fixed voltages contact factory.

TEMPERATURE RANGEPIN CONNECTIONS-40 to 125° C-40 to 125° C-40 to 125° C-40 to 125° C-40 to 125° C-40 to 125° C-40 to 125° C

8L SOIC Top View
GND/ADJ 1

8

VOUT

2

7

VOUT

3

6

VOUT

VIN

4

5

N/C

SOT-223 Top View

3 PIN FIXED/ADJUSTABLE
VERSION
1- Ground/Adjust
2- VOUT
3- VIN

Advanced Monolithic Systems, Inc.

N/C
VOUT

TO-252 FRONT VIEWTAB ISOUTPUT
1

2

3
2
1

3

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AMS1117
ABSOLUTE MAXIMUM RATINGS (Note 1)
Power Dissipation
Input Voltage
Operating Junction Temperature Range
Control Section
Power Transistor
Storage temperature

Internally limited
15V-40°C to 125°C-40°C to 125°C- 65°C to +150°C

Soldering information
Lead Temperature (25 sec)
Thermal ResistanceSO-8 package
TO-252 package
SOT-223 package

265°C
ϕ JA= 160°C/W
ϕ JA= 80°C/W
ϕ JA= 90°C/W** With package soldering to copper area over backside
ground plane or internal power plane ϕ JA can vary from46°C/W to >90°C/W depending on mounting technique andthe size of the copper area.

ELECTRICAL CHARACTERISTICSElectrical Characteristics at IOUT = 0 mA, and TJ = +25°C unless otherwise specified.
Parameter

DeviceConditions

Min

Typ

Max

Units

Reference Voltage(Note 2)

AMS1117

IOUT = 10 mA
1.5V≤ (VIN - VOUT) ≤ 12V

1.232
1.2125

1.250
1.250

1.268
1.2875

V
V

Output Voltage(Note 2)

AMS1117-1.5

VIN = 3V

1.478
1.455

1.500
1.500

1.522
1.545

V
V

AMS1117-1.8

VIN = 3.3V

1.773
1.746

1.800
1.800

1.827
1.854

V
V

AMS1117-2.5

VIN = 4V

2.463
2.425

2.500
2.500

2.537
2.575

V
V

AMS1117-2.85

VIN = 4.35V

2.808
2.7645

2.850
2.850

2.892
2.9355V
V

AMS1117-3.3

VIN = 4.8V

3.251
3.201

3.300
3.300

3.349
3.399

V
V

AMS1117-5.0

VIN = 6.5V

4.925
4.850

5.000
5.000

5.075
5.150

V
V

AMS1117

1.5V≤ (VIN - VOUT) ≤ 12V

0.015
0.035

0.2
0.2

%
%

AMS1117-1.5

1.5V≤ (VIN - VOUT) ≤ 12V

0.3
0.6

5
6

mV
mV

AMS1117-1.8

1.5V≤ (VIN - VOUT) ≤ 12V

0.3
0.6

5
6

mV
mV

AMS1117-2.5

1.5V≤ (VIN - VOUT) ≤ 12V

0.3
0.6

6
6

mV
mV

AMS1117-2.85

1.5V≤ (VIN - VOUT) ≤ 12V

0.3
0.6

6
6

mV
mV

AMS1117-3.3

1.5V≤ (VIN - VOUT) ≤ 12V

0.5
1.0

10
10

mV
mV

AMS1117-5.0

1.5V≤ (VIN - VOUT) ≤ 12V

0.5
1.0

10
10

mV
mV

AMS1117(VIN - VOUT) =1.5V, 10mA ≤ IOUT ≤ 0.8A

0.1
0.2

0.3
0.4

%
%

AMS1117-1.5

VIN = 3V, 0 ≤ IOUT ≤ 0.8A

3
6

10
20

mV
mV

AMS1117-1.8

VIN = 3.3V, 0 ≤ IOUT ≤ 0.8A

3
6

10
20

mV
mV

AMS1117-2.5

VIN = 5V, 0 ≤ IOUT ≤ 0.8A

3
6

12
20

mV
mV

Line Regulation

Load Regulation(Notes 2, 3)

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AMS1117
ELECTRICAL CHARACTERISTICSElectrical Characteristics at IOUT = 0 mA, and TJ = +25°C unless otherwise specified.
Parameter

DeviceConditions

Load Regulation

AMS1117-2.85

Min

Typ

Max

VIN = 4.35V, 0 ≤ IOUT ≤ 0.8A

3
6

12
20

mV
mV

AMS1117-3.3

VIN = 4.75V, 0 ≤ IOUT ≤ 0.8A

3
7

15
25

mV
mV

AMS1117-5.0

VIN = 6.5V, 0 ≤ IOUT ≤ 0.8A

5
10

20
35

mV
mV

Dropout Voltage(VIN - VOUT)AMS1117-1.5/-1.8/-2.5/2.85/-3.3/-5.0∆VOUT , ∆VREF = 1%, IOUT = 0.8A (Note 4)

1.1

1.3

V

Current Limit

AMS1117-1.5/-1.8/-2.5/2.85/-3.3/-5.0(VIN - VOUT) = 1.5V

1,100

1,500

mA

Minimum Load
Current

AMS1117(VIN - VOUT) = 1.5V (Note 5)

5

10

mA

Quiescent Current

AMS1117-1.5/-1.8/-2.5/2.85/-3.3/-5.0

5

11

mA

Ripple Rejection

AMS1117

f =120Hz , COUT = 22µF Tantalum, IOUT = 1A,(VIN-VOUT ) = 3V, CADJ =10µF

60

75

dB

AMS1117-1.5/-1.8/-2.5/2.85

f =120Hz , COUT = 22µF Tantalum, IOUT = 1A,
VIN = 4.35V

60

72

dB

AMS1117-3.3

f =120Hz , COUT = 22µF Tantalum, IOUT = 1A
VIN = 4.75V

60

72

dB

AMS1117-5.0

f =120Hz , COUT = 22µF Tantalum, IOUT = 1A
VIN = 6.5V

60

68

dB

Thermal Regulation

AMS1117

TA = 25°C, 30ms pulse

0.008

Adjust Pin Current

AMS1117

IOUT =10mA , 1.5V≤ (VIN - VOUT) ≤ 12V

55(Notes 2, 3)

Adjust Pin Current
ChangeAMS1117900(VIN - VOUT) = 1.5V

IOUT =10mA, 1.5V≤ (VIN - VOUT) ≤ 12V

Temperature Stability

0.2

Units

0.04

%W

120

µA
µA

5

µA
%

0.5

Long Term Stability

TA =125°C, 1000Hrs

0.3

1

RMS Output Noise

TA = 25°C , 10Hz ≤ f ≤ 10kHz

0.003

%
%

(% of VOUT )Thermal ResistanceJunction-to-Case

All packages

15

°C/W

Parameters identified with boldface type apply over the full operating temperature range.
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. For guaranteed specifications and test conditions, see theElectrical Characteristics. The guaranteed specifications apply only for the test conditions listed.
Note 2: Line and Load regulation are guaranteed up to the maximum power dissipation of 1.2 W for SOT-223, 2.2W for TO-252 and 780mW for 8-Lead
SOIC. Power dissipation is determined by the input/output differential and the output current. Guaranteed maximum power dissipation will not be available
over the full input/output range.
Note 3: See thermal regulation specifications for changes in output voltage due to heating effects. Line and load regulation are measured at a constantjunction temperature by low duty cycle pulse testing. Load regulation is measured at the output lead ~1/8” from the package.
Note 4: Dropout voltage is specified up to 0.8A load. For currents over 0.8A dropout will be higher
Note 5: Minimum load current is defined as the minimum output current required to maintain regulation. When 1.5V ≤ (VIN - VOUT) ≤ 12V the device isguaranteed to regulate if the output current is greater than 10mA.

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AMS1117APPLICATION HINTS
The AMS1117 series of adjustable and fixed regulators are easy to
use and are protected against short circuit and thermal overloads.
Thermal protection circuitry will shut-down the regulator should
the junction temperature exceed 165°C at the sense point.
Pin compatible with older three terminal adjustable regulators,
these devices offer the advantage of a lower dropout voltage, more
precise reference tolerance and improved reference stability withtemperature.

D1

AMS1117
IN
OUT
ADJ

VIN

Stability

VOUT
R1

CADJ

Protection Diodes
Unlike older regulators, the AMS1117 family does not need any
protection diodes between the adjustment pin and the output andfrom the output to the input to prevent over-stressing the die.
Internal resistors are limiting the internal current paths on the
AMS1117 adjustment pin, therefore even with capacitors on theadjustment pin no protection diode is needed to ensure device
safety under short-circuit conditions.
Diodes between the input and output are not usually needed.
Microsecond surge currents of 50A to 100A can be handled by theinternal diode between the input and output pins of the device. In
normal operations it is difficult to get those values of surge
currents even with the use of large output capacitances. If highvalue output capacitors are used, such as 1000µF to 5000µF andthe input pin is instantaneously shorted to ground, damage canoccur. A diode from output to input is recommended, when acrowbar circuit at the input of the AMS1117 is used (Figure 1).

22µFĤigure 1.

Output Voltage
The AMS1117 series develops a 1.25V reference voltage between
the output and the adjust terminal. Placing a resistor between these
two terminals causes a constant current to flow through R1 anddown through R2 to set the overall output voltage. This current isnormally the specified minimum load current of 10mA. Because
IADJ is very small and constant it represents a small error and it
can usually be ignored.

AMS1117
IN
OUT
ADJ

VIN

VOUT
VREF

R1

IADJ

50µA

R2

VOUT = VREF (1+ R2/R1)+IADJR2
Figure 2. Basic Adjustable Regulator

Load Regulation
True remote load sensing it is not possible to provide, because the
AMS1117 is a three terminal device. The resistance of the wire
connecting the regulator to the load will limit the load regulation.
The data sheet specification for load regulation is measured at thebottom of the package. Negative side sensing is a true Kelvinconnection, with the bottom of the output divider returned to thenegative side of the load.
The best load regulation is obtained when the top of the resistor
divider R1 is connected directly to the case not to the load. If R1
were connected to the load, the effective resistance between theregulator and the load would be:
RP x ( R2+R1 ) ,R1Advanced Monolithic Systems, Inc.

COUT

R2

10µF

The circuit design used in the AMS1117 series requires the use ofan output capacitor as part of the device frequency compensation.
The addition of 22µF solid tantalum on the output will ensurestability for all operating conditions.
When the adjustment terminal is bypassed with a capacitor to
improve the ripple rejection, the requirement for an output
capacitor increases. The value of 22µF tantalum covers all cases of
bypassing the adjustment terminal. Without bypassing theadjustment terminal smaller capacitors can be used with equally
good results.
To further improve stability and transient response of thesedevices larger values of output capacitor can be used.

+

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AMS1117APPLICATION HINTS
Connected as shown , RP is not multiplied by the divider ratio

VIN

AMS1117
IN
OUT
ADJ

RP
PARASITIC
LINE RESISTANCE

RL

R1*

R2*

*CONNECT R1 TO CASE

The total thermal resistance from junction to ambient can be as
low as 45°C/W. This requires a reasonable sized PC board with atleast on layer of copper to spread the heat across the board andcouple it into the surrounding air.
Experiments have shown that the heat spreading copper layer does
not need to be electrically connected to the tab of the device. The
PC material can be very effective at transmitting heat between thepad area, attached to the pad of the device, and a ground planelayer either inside or on the opposite side of the board. Although
the actual thermal resistance of the PC material is high, theLength/Area ratio of the thermal resistance between layers issmall. The data in Table 1, was taken using 1/16” FR-4 board with
1 oz. copper foil, and it can be used as a rough guideline for
estimating thermal resistance.
For each application the thermal resistance will be affected bythermal interactions with other components on the board. To
determine the actual value some experimentation will benecessary.
The power dissipation of the AMS1117 is equal to:
PD = ( VIN - VOUT )( IOUT )CONNECT R2 TO LOAD

Maximum junction temperature will be equal to:

Figure 3. Connections for Best Load Regulation

TJ = TA(MAX) + PD(Thermal Resistance (junction-to-ambient))

In the case of fixed voltage devices the top of R1 is connected
Kelvin internally, and the ground pin can be used for negative side
sensing.

Thermal Considerations
The AMS1117 series have internal power and thermal limiting
circuitry designed to protect the device under overload conditions.
However maximum junction temperature ratings of 125°C should
not be exceeded under continuous normal load conditions.
Careful consideration must be given to all sources of thermal
resistance from junction to ambient. For the surface mountpackage SOT-223 additional heat sources mounted near the device
must be considered. The heat dissipation capability of the PC
board and its copper traces is used as a heat sink for the device.
The thermal resistance from the junction to the tab for the
AMS1117 is 15°C/W. Thermal resistance from tab to ambient canbe as low as 30°C/W.

Maximum junction temperature must not exceed 125°C.

Ripple Rejection
The ripple rejection values are measured with the adjustment pin
bypassed. The impedance of the adjust pin capacitor at the ripple
frequency should be less than the value of R1 (normally 100Ω to200Ω) for a proper bypassing and ripple rejection approaching thevalues shown. The size of the required adjust pin capacitor is afunction of the input ripple frequency. If R1=100Ω at 120Hz theadjust pin capacitor should be >13µF. At 10kHz only 0.16µF isneeded.
The ripple rejection will be a function of output voltage, in circuits
without an adjust pin bypass capacitor. The output ripple will
increase directly as a ratio of the output voltage to the reference
voltage (VOUT / VREF ).

Table 1.
COPPER AREATOP SIDE*
BACK SIDE
BOARD AREA
2500 Sq. mm
2500 Sq. mm
2500 Sq. mm
1000 Sq. mm
2500 Sq. mm
2500 Sq. mm
225 Sq. mm
2500 Sq. mm
2500 Sq. mm
100 Sq. mm
2500 Sq. mm
2500 Sq. mm
1000 Sq. mm
1000 Sq. mm
1000 Sq. mm
1000 Sq. mm
01000 Sq. mm* Tab of device attached to topside copper.

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THERMAL RESISTANCE(JUNCTION-TO-AMBIENT)

55°C/W
55°C/W
65°C/W
80°C/W
60°C/W
65°C/W

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AMS1117TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Operating Current(Adjustable Device)

Short-Circuit Current
1.25

9

SHORT CIRCUIT CURRENT (A)MINIMUM OPERATING CURRENT (mA)

12

TJ = 125°C

TJ = 25°C

630

TJ = 125°C

1.00

TJ = 25°C
0.75

0.50

0.25

0
0

5

10

15

0

20

5

Load Regulation
100∆ ILOAD = 1A

90
fRIPPLE = 120Hz

0.05

80
RIPPLE REJECTION (dB)OUTPUT VOLTAGE DEVIATION (%)

15

Ripple Rejection vs. Current

0.10

0

-0.05

-0.10

70

VRIPPLE≤3Vp-p

60
fRIPPLE = 20Hz

50
40

VRIPPLE≤0.5Vp-p

30
20

-0.15

VOUT = 5V
CADJ = 25µF
COUT = 25µF

10
-0.20
-50

10

INPUT/OUTPUT DIFFERENTIALINPUT/OUTPUT DIFFERENTIAL (V)

0
-25

0

25

50

75

100

125

0

0.25

TEMPERATURE (°C)

0.5

0.75

1.0

OUTPUT CURRENT (A)Temperature Stability

Adjust Pin Current

2.0

100

80
1.0

ADJUST PIN CURRENT (µA)

OUTPUT VOLTAGE CHANGE (%)

90

0

-1.0

70
60
50
40
30
20
10

-2.0

0
-50

-25

0

25

50

75

100

125

150

TEMPERATURE (°C)

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-50

-25

0

25

50

75

100

125

150

TEMPERATURE (°C)

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AMS1117
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.

TO-252 PLASTIC PACKAGE (D)0.255-0.265(6.48-6.73)
0.206-0.214(5.23-5.44)

0.087-0.094(2.21-2.39)

0.018-0.023(0.46-0.58)
0.035-0.050(0.89-1.27)

7.0°

0.235-0.245(5.969-6.223)

0.380-0.410(9.65-10.41)

0.035-0.045(0.89-1.14)

0.045-0.060(1.14-1.52)

0.025(0.635)TYP

0.020±0.002(0.510±0.0508)
0.030(0.762)TYP

0.156-0.204(3.96-5.18)

0.018-0.023(0.46-0.58)

D (D3) AMS DRW# 011601

3 LEAD SOT-223 PLASTIC PACKAGE

0.248-0.264(6.30-6.71)
0.116-0.124(2.95-3.15)

0.264-0.287(6.71-7.29)
0.130-0.146(3.30-3.71)

0.033-0.041(0.84-1.04)

0.090(2.29)
NOM

10°-16°
10°
MAX

0.071
(1.80)
MAX

0.010-0.014(0.25-0.36)
10°-16°0.025-0.033(0.64-0.84)

0.012(0.31)
MIN

0.181(4.60)
NOM

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0.025-0.033(0.64-0.84)(SOT-223 ) AMS DRW# 042292

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AMS1117
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued).
8 LEAD SOIC PLASTIC PACKAGE (S)0.189-0.197*(4.801-5.004)
8

7

6

5

0.228-0.244(5.791-6.197)

0.150-0.157**(3.810-3.988)

1

2

3

4

0.010-0.020 x 45°(0.254-0.508)

0.053-0.069(1.346-1.752)
0.004-0.010(0.101-0.254)

0.014-0.019(0.355-0.483)

0.008-0.010(0.203-0.254)

0.050(1.270)TYP

0°-8° TYP

0.016-0.050(0.406-1.270)

S (SO-8 ) AMS DRW# 042293*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASHSHALL NOT EXCEED 0.006" (0.152mm) PER SIDE**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

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