AMS317CM-18 - Advanced Monolithic Systems

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140

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 •• Post Regulators for Switching Supplies

•• 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

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.

ORDERING INFORMATION:

OUTPUT PACKAGE TYPE OPERATING JUNCTION

VOLTAGE 3 Lead TO-220 2 &3 Lead TO-263 TO-252 SOT-223 TEMPERATURE RANGE

ADJUSTABLE AMS317ACT AMS317ACM AMS317ACD AMS317A -40 to +125° C

AMS317CT AMS317CM AMS317CD AMS317 0 to 125° C

FIXED* AMS317ACT-X AMS317ACM-X AMS317ACD-X AMS317A-X -40 to +125° C

AMS317CT-X AMS317CM-X AMS317CD-X AMS317-X 0 to 125° C

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- VOUT

3- VIN

1- Adjust

2- VOUT

3- VIN

SOT-223 Top View

12 3

TAB IS

OUTPUT

TO-252 FRONT VIEW

TAB IS

OUTPUT

TO-263 FRONT VIEW

TAB IS

OUTPUT

2L TO-263 FRONT VIEW

TAB IS

OUTPUT

TO-220 FRONT VIEW

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140

AMS317

ABSOLUTE MAXIMUM RATINGS (Note 1)

Power Dissipation Internally limited Thermal Resistance

Input Voltage 25V TO-220 package ϕ

= 50°C/W

Operating

Junction Temperature Range

TO-263 package ϕ

30°C/W

AMS317A -40°C to +125°C TO-252 package ϕ

= 80°C/W

AMS317 0°C to +125°C SOT-223 package ϕ

= 90°C/W*

Storage temperature - 65°C to +150°C

Soldering information

Lead Temperature (10 sec) 300°C

* With package soldering to copper area over backside

ground

plane or internal power plane ϕ

can vary from 46°C/W to

>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 IOUT = 10 mA, (VIN - VOUT) = 5V, and TJ = +25°C unless otherwise specified.

Parameter Device Conditions AMS317A

Min Typ Max AMS317

Min Typ Max Units

Reference Voltage

(Note 2) AMS317 IOUT = 10 mA

10mA ≤ IOUT ≤ IMAX, 3V≤ (VIN - VOUT) ≤ 25V 1.238

1.225 1.250

1.250 1.262

1.270 1.225

1.20 1.250

1.250 1.270

1.30 V

Output Voltage

(Note 2) AMS317-1.8 0 ≤ IOUT ≤ IMAX, 3.3V≤ VIN ≤ 25V 1.782

1.764 1.800

1.800 1.818

1.836 1.764

1.746 1.800

1.800 1.836

1.854 V

AMS317-2.5 0 ≤ IOUT ≤ IMAX , 4.0V≤ VIN ≤ 25V 2.475

2.460 2.500

2.500 2.525

2.560 2.450

2.425 2.500

2.500 2.550

2.575 V

AMS317-2.85 0 ≤ IOUT ≤ IMAX , 4.35V≤ VIN ≤ 25V 2.82

2.793 2.850

2.850 2.88

2.907 2.793

2.765 2.850

2.850 2.907

2.935 V

AMS317-3.3 0 ≤ IOUT ≤ IMAX, 4.75V ≤ VIN ≤ 25V 3.267

3.235 3.300

3.300 3.333

3.365 3.235

3.201 3.300

3.300 3.365

3.399 V

AMS317-5.0 0 ≤ IOUT ≤ IMAX , 6.5V ≤ VIN ≤ 25V 4.950

4.900 5.000

5.000 5.050

5.100 4.900

4.850 5.000

5.000 5.100

5.150 V

Line Regulation AMS317 ILOAD = 10 mA , 3V≤ (VIN - VOUT) ≤ 25V 0.015

0.035 0.2

0.2 0.015

0.035 0.2

0.2 %

Load Regulation

(Notes 2, 3)

AMS317 10mA ≤ IOUT ≤ IMAX 0.1

0.3 0.5

1.0 0.1

0.3 0.5

1.0 %

Current Limit AMS317/-1.8/-

2.5/-2.85/-3.3/-5.0 (VIN - VOUT) = 5V 1.5 2.0 1.5 2.0 A

Minimum Load

Current AMS317 (VIN - VOUT) = 25V 5 10 5 10 mA

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

Adjust Pin Current AMS317 40 100 40 100 µA

µA

Adjust Pin Current

Change AMS317 10mA ≤ IOUT ≤ IMAX , 3V≤ (VIN - VOUT) ≤ 25V 0.2 50.2 5µA

Temperature

Stability TMIN ≤ TJ ≤ TMAX 1.0 1.0 %

Long Term Stability TA =125°C, 1000Hrs 0.3 10.3 1%

Ripple Rejection AMS317 f =120Hz , COUT = 25µF Tantalum,

(VIN-VOUT ) = 3V, CADJ =10µF66 80 66 80 dB

RMS Output Noise

(% of VOUT ) TA = 25°C , 10Hz ≤ f ≤ 10kHz 0.003 0.003 %

Thermal Resistance

Junction-to-Case TO-252 Package

SOT-223 Package

TO-220 / TO-263 Package

23.5

°C/W

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140

AMS317

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 ≤ (VIN - VOUT) ≤ 25V the device is guaranteed

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

APPLICATION HINTS

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).

AMS317

IN OUT

ADJ +COUT

150

VOUT

CADJ

VIN

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

ADJ

is very small and constant it represents a small

error and it can usually be ignored.

AMS317

IN OUT

ADJ R1

VOUT

VREF

VIN

IADJ

VOUT = VREF (1+ R2/R1)+IADJR2

Figure 2. Basic Adjustable Regulator

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140

AMS317

APPLICATION HINTS

Load Regulation

True remote load sensing it is not possible to provide, because the

AMS317 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:

RP x ( R2+R1 ) , RP = Parasitic Line Resistance

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

AMS317

IN OUT

ADJ

R1*

R2*

PARASITIC

LINE RESISTANCE

*CONNECT R1 TO CASE

CONNECT R2 TO LOAD

Figure 3. Connections for Best Load Regulation

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 AMS317 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

AMS317 is 15°C/W; thermal resistance from tab to ambient can

be as low as 30°C/W. 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.

For the TO-252 package, if the maximum allowable value is

found to be ≥92°C/W, no heat sink is needed since the package

alone will dissipate enough heat to satisfy these requirements. If

the calculated value for θ

falls bellow these limits, a heat sink

is required.

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 AMS317 is equal to:

PD = ( VIN - VOUT )( IOUT )

Maximum junction temperature will be equal to:

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

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 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.

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 ).

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140

AMS317

Table 1.

COPPER AREA THERMAL RESISTANCE

TOP SIDE* BACK SIDE BOARD AREA (JUNCTION-TO-AMBIENT)

2500 Sq. mm 2500 Sq. mm 2500 Sq. mm 45°C/W

1000 Sq. mm 2500 Sq. mm 2500 Sq. mm 45°C/W

225 Sq. mm 2500 Sq. mm 2500 Sq. mm 53°C/W

100 Sq. mm 2500 Sq. mm 2500 Sq. mm 59°C/W

1000 Sq. mm 1000 Sq. mm 1000 Sq. mm 52°C/W

1000 Sq. mm 01000 Sq. mm 55°C/W

* Tab of device attached to topside copper.

TYPICAL PERFORMANCE CHARACTERISTICS

Minimum Operating Current

(Adjustable Device) Short-Circuit Current

Load Regulation Ripple Rejection vs. Current

0 5 10 15 20

INPUT/OUTPUT DIFFERENTIAL (V)

0 5 10 15

MINIMUM OPERATING CURRENT (mA)

INPUT/OUTPUT DIFFERENTIAL

0.25

0.50

0.75

1.00

1.25

SHORT CIRCUIT CURRENT (A)

-50 -25 0 25 50 75 100 125

-0.20

-0.15

-0.10

-0.05

0.05

0.10

TEMPERATURE (°C)

OUTPUT VOLTAGE DEVIATION (%)

00.2 0.4 0.6 0.8

100

OUTPUT CURRENT (A)

RIPPLE REJECTION (dB)

TJ = 125°C

TJ = 25°C

fRIPPLE = 120Hz

fRIPPLE = 20Hz

VRIPPLE

≤

3Vp-p

VRIPPLE

≤

0.5Vp-p

∆

ILOAD = 1A

VOUT = 5V

CADJ = 25

COUT = 25

TJ = 25°C

TJ =

125°C

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140

AMS317

TYPICAL PERFORMANCE CHARACTERISTICS (Continued).

PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.

3 LEAD TO-220 PLASTIC PACKAGE (T)

Adjust Pin Current

Temperature Stability

-50 -25 0 25 50 75 100 125 150

-2.0

-1.0

1.0

2.0

TEMPERATURE (°C)

OUTPUT VOLTAGE CHANGE (%)

TEMPERATURE (°C)

-50 -25 0 25 50 75 100 125 150

100

ADJUST PIN CURRENT (

0.330-0.370

0.050

(8.382-9.398)

0.090-0.110

(2.286-2.794) (1.270)

TYP

0.390-0.415

(9.906-10.541) 0.165-0.180

(4.191-4.572) 0.045-0.055

(1.143-1.397)

0.095-0.115

(2.413-2.921)

0.013-0.023

(0.330-0.584)

T (TO-220) AMS DRW# 042193

0.147-0.155

(3.734-3.937)

DIA

0.230-0.270

(5.842-6.858)

0.460-0.500

(11.684-12.700)

0.570-0.620

(14.478-15.748)

0.218-0.252

(5.537-6.401)

0.520-0.570

(13.208-14.478)

0.980-1.070

(24.892-27.178)

0.028-0.038

(0.711-0.965)

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140

AMS317

PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued).

3 LEAD TO-263 PLASTIC DD (M)

2 LEAD TO-263 PLASTIC DD (M)

0.330-0.370

0.032

0.060

(1.524)

TYP

(8.382-9.398)

(5.05-5.54 )

0.090-0.110

(2.286-2.794)

0.199-0.218

(0.81)

TYP

0.390-0.415

(9.906-10.541)

0.165-0.180

(4.191-4.572) 0.045-0.055

(1.143-1.397)

0.095-0.115

(2.413-2.921)

0.90-0.110

(2.29-2.79)

0.013-0.023

(0.330-0.584)

0.108

(2.74)

TYP

(0.102 )

+0.203

-0.102

0.004 +0.008

-0.004

M (DD2) AMS DRW# 072191

0.0295

(0.7495)

TYP

0.330-0.370

0.032

0.060

(1.524)

TYP

(8.382-9.398)

(5.05-5.54 )

0.090-0.110

(2.286-2.794)

0.199-0.218

(0.81)

TYP

0.390-0.415

(9.906-10.541)

0.165-0.180

(4.191-4.572) 0.045-0.055

(1.143-1.397)

0.095-0.115

(2.413-2.921)

0.90-0.110

(2.29-2.79)

0.013-0.023

(0.330-0.584)

0.108

(2.74)

TYP

(0.102 )

+0.203

-0.102

0.004 +0.008

-0.004

M (DD3) AMS DRW# 042191R1

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140

AMS317

PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued).

TO-252 PLASTIC PACKAGE (D)

3 LEAD SOT-223 PLASTIC PACKAGE

0.130-0.146

(3.30-3.71)

0.248-0.264

(6.30-6.71)

0.116-0.124

(2.95-3.15)

0.264-0.287

(6.71-7.29)

0.090

(2.29)

NOM

0.071

(1.80)

MAX

0.033-0.041

(0.84-1.04)

0.025-0.033

(0.64-0.84)

0.181

(4.60)

NOM

0.012

(0.31)

MIN

0.025-0.033

(0.64-0.84)

10°

MAX

10°-16°

0.010-0.014

(0.25-0.36)

(SOT-223 ) AMS DRW# 042292

0.030

(0.762)

TYP

0.085-0.095

(2.159-2.413) 0.030-0.034

(0.762-0.863)

0.024±0.002

(0.610±0.0508)

0.018-0.022

(0.451-0.558)

0.038

(0.965)

TYP

D (D3) AMS DRW# 042891

0.038-0.042

(0.965-1.066)

0.038-0.042

(0.965-1.066)

0.235-0.245

(5.969-6.223)

0.088-0.092

(2.235-2.336)

0.099-0.103

(2.514-2.615)

0.175-0.180

(4.191-4.445)

0.023-0.027

(0.584-0.685)

0.020-0.030

(0.508-0.762)

0.258-0.262

(6.553-6.654)

0.033-0.037

(0.838-0.939)

0.020-0.030

(0.508-0.762)

0.208-0.212

(5.283-5.384)

0.025

(0.635)

TYP

0.057-0.067

(0.144-0.170)

DIA

45.0° 7.0°