ADMOS AMS317CT-5.0, AMS317CT-3.3, AMS317CT-2.85, AMS317CT-2.5, AMS317CT-1.8 Datasheet

Advanced AMS317
Monolithic 1A LOW DROPOUT VOLTAGE REGULATOR

Systems

FEATURES APPLICATIONS

•• Three Terminal Adjustable or Fixed Voltages* •• High Efficiency Linear Regulators

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

•• Output Current of 1A •• 5V to 3.3V Linear Regulator

•• Operates Down to 1V Dropout •• Battery Chargers

•• Line Regulation: 0.2% Max. •• Active SCSI Terminators

•• Load Regulation: 0.4% Max. •• Power Management for Notebook

••TO-220, TO-263, TO-252 and SOT-223 package available •• Battery Powered Instrumentation

GENERAL DESCRIPTION

The AMS317 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 AMS317 devices are pin compatible with other three-terminal regulators and are offered in 3 lead TO-220 package, in
the 2 & 3 Lead TO-263 (Plastic DD), in the TO-252 (D PAK) and in the low profile surface mount SOT-223 package.

•• Post Regulators for Switching Supplies

ORDERING INFORMATION:

OUTPUT PACKAGE TYPE OPERATING JUNCTION

VOLTAGE

ADJUSTABLE AMS317ACT AMS317ACM AMS317ACD AMS317A

FIXED* AMS317ACT-X AMS317ACM-X AMS317ACD-X AMS317A-X

X= 1.8V, 2.5V, 2.85V, 3.3V and 5.0V.
*For additional available fixed voltages contact factory.

PIN CONNECTIONS

FIXED VERSION ADJUSTABLE VERSION

1- Ground
2- V

OUT

3- V

IN

3 Lead TO-220 2 &3 Lead TO-263 TO-252 SOT-223

AMS317CT AMS317CM AMS317CD AMS317

AMS317CT-X AMS317CM-X AMS317CD-X AMS317-X

SOT-223 Top View

1- Adjust
2- V

OUT

3- V

IN

TAB IS

OUTPUT

TO-220 FRONT VIEW

3
2

1

TAB IS

OUTPUT

1

2 3

TO-252 FRONT VIEW

3
2
1

TEMPERATURE RANGE

-40 to +125° C
0 to 125° C

-40 to +125° C
0 to 125° C

TO-263 FRONT VIEW

TAB IS

OUTPUT

2L TO-263 FRONT VIEW

TAB IS

OUTPUT

3
2
1

3
2
1

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone [phone] Fax [phone]

ABSOLUTE MAXIMUM RATINGS (Note 1)

Junction Temperature Range

JA

Power Dissipation Internally limited Thermal Resistance
Input Voltage 25V TO-220 package
Operating
AMS317A
AMS317
Storage temperature
Soldering information
Lead Temperature (10 sec)

-40°C to +125°C
0°C to +125°C

- 65°C to +150°C

300°C

TO-263 package
TO-252 package
SOT-223 package

* With package soldering to copper area over backside ground
plane or internal power plane ϕ
>90°C/W (for SOT-223) (20°C/W to >40°C/W for TO-263)
depending on mounting technique and the size of the copper
area.

ELECTRICAL CHARACTERISTICS

Electrical Characteristics at I

= 10 mA, (VIN - V

OUT

) = 5V, and TJ = +25°C unless otherwise specified.

OUT

AMS317

ϕ JA= 50°C/W

ϕ JA= 30°C/W

ϕ JA= 80°C/W

ϕ JA= 90°C/W*

can vary from 46°C/W to

Parameter Device Conditions AMS317A

Min Typ Max

Reference Voltage
(Note 2)

Output Voltage
(Note 2)

Line Regulation AMS317

Load Regulation
(Notes 2, 3)

Current Limit AMS317/-1.8/-

AMS317 I

AMS317-1.8

AMS317-2.5

AMS317-2.85

AMS317-3.3

AMS317-5.0

AMS317

= 10 mA

OUT

10mA ≤ I

0 ≤ I

0 ≤ I

0 ≤ I

0 ≤ I

0 ≤ I
I

LOAD

10mA ≤ I

(VIN - V

≤ I

OUT

≤ I

OUT

OUT

OUT

OUT

OUT

, 3.3V≤ VIN ≤ 25V

MAX

≤ I

, 4.0V≤ VIN ≤ 25V

MAX

≤ I

, 4.35V≤ VIN ≤ 25V

MAX

≤ I

, 4.75V ≤ VIN ≤ 25V

MAX

≤ I

, 6.5V ≤ VIN ≤ 25V

MAX

= 10 mA , 3V≤ (VIN - V

≤ I

OUT

) = 5V

OUT

, 3V≤ (VIN - V

MAX

MAX

OUT

) ≤ 25V

OUT

) ≤ 25V

1.238

1.225

1.782

1.764

2.475

2.460

2.82

2.793

3.267

3.235

4.950

4.900

1.250

1.250

1.800

1.800

2.500

2.500

2.850

2.850

3.300

3.300

5.000

5.000

0.015

0.035

0.1

0.3

1.5 2.0 1.5 2.0

1.262

1.270

1.818

1.836

2.525

2.560

2.88

2.907

3.333

3.365

5.050

5.100

0.2

0.2

0.5

1.0

AMS317

Min Typ Max

1.225

1.764

1.746

2.450

2.425

2.793

2.765

3.235

3.201

4.900

4.850

1.20

1.250

1.250

1.800

1.800

2.500

2.500

2.850

2.850

3.300

3.300

5.000

5.000

0.015

0.035

0.1

0.3

1.270

1.30

1.836

1.854

2.550

2.575

2.907

2.935

3.365

3.399

5.100

5.150

0.2

0.2

0.5

1.0

Units

V
V

V
V

V
V

V
V

V
V

V
V

%
%

%
%

A

2.5/-2.85/-3.3/-5.0

Minimum Load

AMS317 (VIN - V

OUT

) = 25V

5 10 5 10

mA

Current
Thermal Regulation AMS317 TA = 25°C, 20ms pulse 0.04 0.07 0.04 0.07 %W

Adjust Pin Current AMS317 40

Adjust Pin Current
Change

Temperature
Stability

AMS317

10mA ≤ I

T

≤ TJ ≤ T

MIN

OUT

≤ I

MAX

MAX

, 3V≤ (VIN - V

OUT

) ≤ 25V

0.2 5 0.2 5

1.0 1.0

100

40

100

µA
µA

µA

Long Term Stability TA =125°C, 1000Hrs 0.3 1 0.3 1 %
Ripple Rejection AMS317

RMS Output Noise
(% of V

OUT

)

Thermal Resistance
Junction-to-Case

f =120Hz , C
(VIN-V

OUT

= 25µF Tantalum,

OUT

) = 3V, C

ADJ

=10µF

TA = 25°C , 10Hz ≤ f ≤ 10kHz

TO-252 Package
SOT-223 Package
TO-220 / TO-263 Package

66 80 66 80

0.003 0.003 %

5

23.5
5

5

23.5
5

°C/W
°C/W
°C/W

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone [phone] Fax [phone]

%

dB

AMS317

ADJ

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. Parameters identified with boldface type apply over the full
operating temperature range.

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: Minimum load current is defined as the minimum output current required to maintain regulation. When 3V ≤ (V

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

APPLICATION HINTS

- V

) ≤ 25V the device is guaranteed

IN

OUT

The AMS317 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.

Stability

The circuit design used in the AMS317 series requires the use of
an output capacitor as part of the device frequency compensation.
The addition of 150µF aluminum electrolytic or a 22µF solid
tantalum on the output will ensure stability 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 or 150µF
aluminum covers all cases of bypassing the adjustment terminal.
Without bypassing the adjustment terminal smaller capacitors can
be used with equally good results.
To ensure good transient response with heavy load current
changes capacitor values on the order of 100µF are used in the
output of many regulators. To further improve stability and
transient response of these devices larger values of output
capacitor can be used.

Protection Diodes

Unlike older regulators, the AMS317 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
AMS317 adjustment pin, therefore even with capacitors on the
adjustment 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 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 AMS317 is used (Figure 1).

D1

V

IN

IN OUT

ADJ

C

10µF

ADJ

+

R

1

R

2

AMS317

C

150µF

OUT

V

OUT

Figure 1.

Output Voltage

The AMS317 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

is very small and constant it represents a small

error and it can usually be ignored.

V

IN

V

OUT

IN OUT

ADJ

I

ADJ

50µA

= V

(1+ R2/R1)+I

REF

V

REF

ADJ

AMS317

R2

R1

R2

V

OUT

Figure 2. Basic Adjustable Regulator

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone [phone] Fax [phone]