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Advanced

Monolithic

Systems

AMS1117

1A LOW DROPOUT VOLTAGE REGULATOR

RoHS compliant

FEATURES

APPLICATIONS

• Three Terminal Adjustable or Fixed Voltages*

1.5V, 1.8V, 2.5V, 2.85V, 3.3V and 5.0V

• Output Current of 1A

• High Efficiency Linear Regulators

• Post Regulators for Switching Supplies

• 5V to 3.3V Linear Regulator

• Battery Chargers

• Operates Down to 1V Dropout

• Line Regulation: 0.2% Max.

• Load Regulation: 0.4% Max.

• SOT-223, TO-252 and SO-8 package available

• Active SCSI Terminators

• Power Management for Notebook

• Battery Powered Instrumentation

GENERAL DESCRIPTION

The AMS1117 series of adjustable and fixed voltage regulators are designed to provide 1A output current and to operate

down to 1V input-to-output differential. The dropout voltage of the device is guaranteed maximum 1.3V at maximum output

current, decreasing at lower load currents.

On-chip trimming adjusts the reference voltage to 1%. Current limit is also trimmed, minimizing 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 TYPE

SOT-223

OPERATING JUNCTION

TEMPERATURE RANGE

TO-252

8L SOIC

AMS1117CD

AMS1117

AMS1117CS

-40 to 125° C

AMS1117CD-1.5 AMS1117-1.5

AMS1117CD-1.8 AMS1117-1.8

AMS1117CD-2.5 AMS1117-2.5

AMS1117CD-2.85 AMS1117-2.85

AMS1117CD-3.3 AMS1117-3.3

AMS1117CD-5.0 AMS1117-5.0

AMS1117CS-1.5

AMS1117CS-1.8

AMS1117CS-2.5

AMS1117CS-2.85

AMS1117CS-3.3

AMS1117CS-5.0

8L SOIC Top View

1

2

3

4

8

7

6

5

GND/ADJ

V_OUT

N/C

V_OUT

N/C

*For additional available fixed voltages contact factory.

V_IN

PIN CONNECTIONS

SOT-223 Top View

TO-252 FRONT VIEW

3 PIN FIXED/ADJUSTABLE

VERSION

3

2

1

TAB IS

OUTPUT

1- Ground/Adjust

2- V_OUT

1

2

3

3- V_IN

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS1117

ABSOLUTE MAXIMUM RATINGS (Note 1)

Power Dissipation

Input Voltage

Internally limited

Soldering information

Lead Temperature (25 sec)

Thermal Resistance

SO-8 package

TO-252 package

SOT-223 package

* With package soldering to copper area over backside

15V

265°C

Operating Junction Temperature

Control Section

Power Transistor

0°C to 125°C

0°C to 150°C

- 65°C to +150°C

ϕ

_JA= 160°C/W

_JA= 80°C/W

_JA= 90°C/W*

ϕ

Storage temperature

ground plane or internal power plane ϕ

can vary from

JA

46°C/W to >90°C/W depending on mounting technique and

the size of the copper area.

ELECTRICAL CHARACTERISTICS

Electrical Characteristics at I_OUT= 0 mA, and T_J= +25°C unless otherwise specified.

Parameter

Device

Conditions

Min

Typ

Max

Units

Reference Voltage

(Note 2)

AMS1117

I_OUT= 10 mA

10mA ≤ I_OUT≤ 1A, 1.5V≤ (V_IN- V_OUT) ≤ 12V

1.238

1.225

1.250

1.262

1.270

V

Output Voltage

(Note 2)

AMS1117-1.5

AMS1117-1.8

AMS1117-2.5

AMS1117-2.85

AMS1117-3.3

AMS1117-5.0

AMS1117

1.485

1.476

1.500

1.515

1.524

V

0 ≤ I_OUT≤ 1A , 3.0V≤ V_IN≤ 12V

0 ≤ I_OUT≤ 1A , 3.3V≤ V_IN≤ 12V

0 ≤ I_OUT≤ 1A , 4.0V≤ V_IN≤ 12V

0 ≤ I_OUT≤ 1A , 4.35V≤ V_IN≤ 12V

0 ≤ I_OUT≤ 1A , 4.75V ≤ V_IN≤ 12V

0 ≤ I_OUT≤ 1A , 6.5V ≤ V_IN≤ 12V

I_LOAD= 10 mA , 1.5V≤ (V_IN- V_OUT) ≤ 12V

3.0V≤ V_IN≤ 12V

1.782

1.773

1.800

1.818

1.827

V

2.475

2.460

2.500

2.525

2.560

V

2.82

2.79

2.850

2.88

2.91

V

3.267

3.235

3.300

3.333

3.365

V

4.950

4.900

5.000

5.050

5.100

V

Line Regulation

0.015

0.035

0.2

%

AMS1117-1.5

AMS1117-1.8

AMS1117-2.5

AMS1117-2.85

AMS1117-3.3

AMS1117-5.0

0.3

0.6

5

6

mV

0.3

0.6

5

6

mV

3.3V≤ V_IN≤ 12V

0.3

0.6

6

mV

4.0V≤ V_IN≤ 12V

0.3

0.6

6

mV

4.35V≤ V_IN≤ 12V

0.5

1.0

10

mV

4.75V≤ V_IN≤ 12V

0.5

1.0

10

mV

6.5V≤ V_IN≤ 12V

Load Regulation

(Notes 2, 3)

AMS1117

0.1

0.2

0.3

0.4

%

(V_IN- V_OUT) =3V, 10mA ≤ I_OUT≤ 1A

AMS1117-1.5

AMS1117-1.8

AMS1117-2.5

3

6

10

20

mV

V_IN= 5V, 0 ≤ I_OUT≤ 1A

3

6

10

20

mV

3

6

12

20

mV

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS1117

ELECTRICAL CHARACTERISTICS

Electrical Characteristics at I_OUT= 0 mA, and T_J= +25°C unless otherwise specified.

Parameter

Device

Conditions

Min

Typ

Max

Units

Load Regulation

(Notes 2, 3)

AMS1117-2.85

3

6

12

20

mV

V_IN= 5V, 0 ≤ I_OUT≤ 1A

AMS1117-3.3

AMS1117-5.0

3

7

15

25

mV

V_IN= 5V, 0 ≤ I_OUT≤ 1A

V_IN= 8V, 0 ≤ I_OUT≤ 1A

5

10

20

35

mV

Dropout Voltage

AMS1117-1.5/-1.8/-2.5/-

2.85/-3.3/-5.0

V

1.1

1.3

∆V_OUT, ∆V_REF= 1%, I_OUT= 1A (Note 4)

(V_IN- V

)

OUT

Current Limit

AMS1117-1.5/-1.8/-2.5/-

2.85/-3.3/-5.0

(V_IN- V_OUT) = 5V

mA

900

1,100

1,500

Minimum Load

Current

AMS1117

(V_IN- V_OUT) = 12V (Note 5)

mA

5

10

V_IN≤ 12V

Quiescent Current

AMS1117-1.5/-1.8/-2.5/-

2.85/-3.3/-5.0

Ripple Rejection

AMS1117

dB

60

75

72

68

f =120Hz , C_OUT= 22µF Tantalum, I_OUT= 1A,

(V_IN-V_OUT) = 3V, C_ADJ=10µF

AMS1117-1.5/-1.8/-2.5/-

2.85

f =120Hz , C_OUT= 22µF Tantalum, I_OUT= 1A,

V_IN= 6V

AMS1117-3.3

dB

f =120Hz , C_OUT= 22µF Tantalum, I_OUT= 1A

V_IN= 6.3V

AMS1117-5.0

dB

f =120Hz , C_OUT= 22µF Tantalum, I_OUT= 1A

V_IN= 8V

Thermal Regulation

Adjust Pin Current

AMS1117

T_A= 25°C, 30ms pulse

0.008

55

0.04

%W

10mA ≤ I_OUT≤ 1A , 1.5V≤ (V_IN- V_OUT) ≤ 12V

µA

120

5

Adjust Pin Current

Change

AMS1117

0.2

10mA ≤ I_OUT≤ 1A , 1.5V≤ (V_IN- V_OUT) ≤ 12V

µA

Temperature Stability

Long Term Stability

RMS Output Noise

%

0.5

0.3

T_A=125°C, 1000Hrs

1

0.003

T_A= 25°C , 10Hz ≤ f ≤ 10kHz

(% of V_OUT

)

Thermal Resistance

Junction-to-Case

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 the

Electrical 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. 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 constant junction

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 over the full output current range of the device.

Note 5: Minimum load current is defined as the minimum output current required to maintain regulation. When 1.5V ≤ (V_IN- V_OUT) ≤ 12V the device is

guaranteed to regulate if the output current is greater than 10mA.

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS1117

APPLICATION 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 with

temperature.

D1

AMS1117

V_OUT

V_IN

IN

OUT

ADJ

+

C_OUT

R₁

2

2µF

Stability

C_ADFJ

R₂

10

µ

The circuit design used in the AMS1117 series requires the use of

an output capacitor as part of the device frequency compensation.

The addition of 22µF solid tantalum on the output will ensure

stability for all operating conditions.

Figure 1.

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 the

adjustment terminal smaller capacitors can be used with equally

good results.

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 and

down through R2 to set the overall output voltage. This current is

normally the specified minimum load current of 10mA. Because

I_ADJis very small and constant it represents a small error and it

can usually be ignored.

To further improve stability and transient response of these

devices larger values of output capacitor can be used.

Protection Diodes

Unlike older regulators, the AMS1117 family does not need any

protection diodes between the adjustment pin and the output and

from 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 the

adjustment pin no protection diode is needed to ensure device

safety under short-circuit conditions.

AMS1117

V_OUT

V_IN

IN

OUT

ADJ

V_REF

R1

R2

I_ADJ

50µA

Diodes between the input and output are not usually needed.

Microsecond surge currents of 50A to 100A can be handled by the

internal 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 high

value output capacitors are used, such as 1000µF to 5000µF and

the input pin is instantaneously shorted to ground, damage can

occur. A diode from output to input is recommended, when a

crowbar circuit at the input of the AMS1117 is used (Figure 1).

V_OUT= V_REF(1+ R2/R1)+I_ADJR2

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 the

bottom of the package. Negative side sensing is a true Kelvin

connection, with the bottom of the output divider returned to the

negative 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 the

regulator and the load would be:

R_Px ( R2+R1 ) , R_P= Parasitic Line Resistance

R1

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS1117

APPLICATION HINTS

Connected as shown , R_Pis not multiplied by the divider ratio

The total thermal resistance from junction to ambient can be as

low as 45°C/W. This requires a reasonable sized PC board with at

least on layer of copper to spread the heat across the board and

couple 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 the

pad area, attached to the pad of the device, and a ground plane

layer either inside or on the opposite side of the board. Although

the actual thermal resistance of the PC material is high, the

Length/Area ratio of the thermal resistance between layers is

small. 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.

R_P

PARASITIC

LINE RESISTANCE

AMS1117

V_IN

IN

OUT

ADJ

R_L

R1*

R2*

For each application the thermal resistance will be affected by

thermal interactions with other components on the board. To

determine the actual value some experimentation will be

necessary.

The power dissipation of the AMS1117 is equal to:

*CONNECT R1 TO CASE

CONNECT R2 TO LOAD

P_D= ( V_IN- V_OUT)( I_OUT

)

Maximum junction temperature will be equal to:

Figure 3. Connections for Best Load Regulation

T_J= T_A(MAX)+ P_D(Thermal Resistance (junction-to-ambient))

Maximum junction temperature must not exceed 125°C.

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.

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 to

200Ω) for a proper bypassing and ripple rejection approaching the

values shown. The size of the required adjust pin capacitor is a

function of the input ripple frequency. If R1=100Ω at 120Hz the

adjust pin capacitor should be >13µF. At 10kHz only 0.16µF is

needed.

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 mount

package 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

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 (V_OUT/ V_REF).

AMS1117 is 15°C/W. Thermal resistance from tab to ambient can

be as low as 30°C/W.

Table 1.

COPPER AREA

THERMAL RESISTANCE

(JUNCTION-TO-AMBIENT)

TOP SIDE*

BACK SIDE

2500 Sq. mm

BOARD AREA

2500 Sq. mm

1000 Sq. mm

225 Sq. mm

100 Sq. mm

1000 Sq. mm

45°C/W

53°C/W

59°C/W

52°C/W

55°C/W

2500 Sq. mm

1000 Sq. mm

0

2500 Sq. mm

1000 Sq. mm

* Tab of device attached to topside copper.

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS1117

TYPICAL PERFORMANCE CHARACTERISTICS

Minimum Operating Current

Short-Circuit Current

(Adjustable Device)

12

1.25

1.00

0.75

0.50

0.25

0

T_J= 125°C

9

T_J= 25°C

T_J= 125°C

T_J= 25°C

6

3

0

5

10

15

20

0

5

10

15

INPUT/OUTPUT DIFFERENTIAL

INPUT/OUTPUT DIFFERENTIAL (V)

Load Regulation

Ripple Rejection vs. Current

0.10

0.05

100

90

80

70

60

50

40

30

20

10

0

∆

I_LOAD= 1A

f_RIPPLE= 120Hz

V_RIPPLE≤3Vp-p

0

f_RIPPLE= 20Hz

-0.05

V_RIPPLE≤0.5Vp-p

-0.10

-0.15

-0.20

V_OUT= 5V

C_ADJ= 25

C_OUT= 25

µ

F

µF

-50

-25

0

25

50

75

100

125

0

0.25

0.5

0.75

1.0

TEMPERATURE (°C)

OUTPUT CURRENT (A)

Temperature Stability

Adjust Pin Current

2.0

1.0

0

100

90

80

70

60

50

40

30

20

10

0

-1.0

-2.0

-50

-25

0

25

50

75

100

125

150

-50

-25

0

25

50

75

100

125

150

TEMPERATURE (°C)

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS1117

PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.

TO-252 PLASTIC PACKAGE (D)

0.255-0.265

(6.48-6.73)

0.087-0.094

(2.21-2.39)

0.206-0.214

(5.23-5.44)

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

0.018-0.023

(0.46-0.58)

0.156-0.204

(3.96-5.18)

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°

0.012

(0.31)

MIN

0.025-0.033

(0.64-0.84)

0.025-0.033

(0.64-0.84)

(SOT-223 ) AMS DRW# 042292

0.181

(4.60)

NOM

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

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

(0.254-0.508)

x 45°

0.053-0.069

(1.346-1.752)

0.004-0.010

(0.101-0.254)

0.008-0.010

(0.203-0.254)

0°-8° TYP

0.014-0.019

(0.355-0.483)

0.050

(1.270)

TYP

0.016-0.050

(0.406-1.270)

S (SO-8 ) AMS DRW# 042293

*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH

SHALL 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

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

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