AMS1085CM-30 - Advanced Monolithic Systems

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

Advanced AMS1085

Monolithic 3A LOW DROPOUT VOLTAGE REGULATOR

Systems

FEATURES APPLICATIONS

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

1.5V, 2.5V, 2.85V, 3.0V, 3.3V, 3.5V and 5.0V •• Post Regulators for Switching Supplies

•• Output Current of 3A •• Microprocessor Supply

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

•• Load Regulation: 0.1% •• Constant Current Regulators

•• Line Regulation: 0.015% •• Notebook/Personal Computer Supplies

•• TO-220, TO-263 and TO-252 packages available •• Portable Instrumentation

GENERAL DESCRIPTION

The

The AMS1085 series of adjustable and fixed voltage regulators are designed to provide 3A output current and to operate

down to 1V input-to-output differential. The dropout voltage of the device is guaranteed maximum 1.5V 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 AMS1085 devices are pin compatible with older three-terminal regulators and are offered in 3 lead TO-220 package, 3

and 2 lead TO-263 (Plastic DD) and TO-252 (D PAK) package.

ORDERING INFORMATION:

PACKAGE TYPE OPERATING JUNCTION

3 LEAD TO-220 2&3 LEAD TO-263 TO-252 TEMPERATURE RANGE

AMS1085CT AMS1085CM AMS1085CD 0 to 125° C

AMS1085CT-1.5 AMS1085CM-1.5 AMS1085CD-1.5 0 to 125° C

AMS1085CT-2.5 AMS1085CM-2.5 AMS1085CD-2.5 0 to 125° C

AMS1085CT-2.85 AMS1085CM-2.85 AMS1085CD-2.85 0 to 125° C

AMS1085CT-3.0 AMS1085CM-3.0 AMS1085CD-3.0 0 to 125° C

AMS1085CT-3.3 AMS1085CM-3.3 AMS1085CD-3.3 0 to 125° C

AMS1085CT-3.5 AMS1085CM-3.5 AMS1085CD-3.5 0 to 125° C

AMS1085CT-5.0 AMS1085CM-5.0 AMS1085CD-5.0 0 to 125° C

PIN CONNECTIONS

FIXED VERSION ADJUSTABLE VERSION

1- Ground

2- VOUT

3- VIN

1- Adjust

2- VOUT

3- VIN

TAB IS

OUTPUT

TO-252 FRONT VIEW

TAB IS

OUTPUT

2L TO-263 FRONT VIEW

TAB IS

OUTPUT

TO-220 FRONT VIEW

TAB IS

OUTPUT

3L TO-263 FRONT VIEW

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

AMS1085

ABSOLUTE MAXIMUM RATINGS (Note 1)

Power Dissipation Internally limited Soldering information

Input Voltage 15V Lead Temperature (10 sec) 300°C

Operating

Junction Temperature Range

Thermal Resistance

Control Section 0°C to 125°C TO-220 package ϕ

= 50°C/W

Power Transistor 0°C to 150°C TO-263 package ϕ

30°C/W *

Storage temperature - 65°C to +150°C TO-252 package ϕ

100°C/W

* With package soldering to 0.5in

copper area over

backside ground plane or internal power plane ϕ

can vary

from 20°C/W to >40°C/W depending on mounting

technique.

ELECTRICAL CHARACTERISTICS

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

Parameter Device Conditions Min Typ Max Units

Reference Voltage

(Note 2) AMS1085 IOUT = 10 mA

10mA ≤ IOUT ≤ 3A, 1.5V≤ (VIN - VOUT) ≤ 12V 1.238

1.225 1.250

1.250 1.262

1.270 V

Output Voltage

(Note 2) AMS1085-1.5 0 ≤ IOUT ≤ 3A , 3V≤ VIN ≤ 12V 1.485

1.470 1.500

1.500 1.515

1.530 V

AMS1085-2.5 0 ≤ IOUT ≤ 3A , 4V≤ VIN ≤ 12V 2.475

2.450 2.500

2.500 2.525

2.550 V

AMS1085-2.85 0 ≤ IOUT ≤ 3A , 4.35V≤ VIN ≤ 12V 2.82

2.79 2.850

2.850 2.88

2.91 V

AMS1085-3.0 0 ≤ IOUT ≤ 3A , 4.5V ≤ VIN ≤ 12V 2.970

2.940 3.000

3.000 3.300

3.360 V

AMS1085-3.3 0 ≤ IOUT ≤ 3A , 4.75V ≤ VIN ≤ 12V 3.267

3.235 3.300

3.300 3.333

3.365 V

AMS1085-3.5 0 ≤ IOUT ≤ 3A , 5V ≤ VIN ≤ 12V 3.465

3.430 3.500

3.500 3.535

3.570 V

AMS1085-5.0 0 ≤ IOUT ≤ 3A , 6.5V ≤ VIN ≤ 12V 4.950

4.900 5.000

5.000 5.050

5.100 V

Line Regulation AMS1085/-1.5/-2.5/-2.85/

-3.0/-3.3/-3.5/-5.0 ILOAD = 10 mA , 1.5V≤ (VIN - VOUT) ≤ 12V 0.3

0.6 10

10 mV

Load Regulation

(Notes 2, 3)

AMS1085 (VIN - VOUT) =3V, 10mA ≤ IOUT ≤ 3A 0.1

0.2 .03

.04 %

AMS1085-1.5 VIN = 5V, 0 ≤ IOUT ≤ 3A 3

612

20 mV

AMS1085-2.5 VIN = 5V, 0 ≤ IOUT ≤ 3A 3

612

20 mV

AMS1085-2.85 VIN = 5V, 0 ≤ IOUT ≤ 3A 3

612

20 mV

AMS1085-3.0 VIN = 5V, 0 ≤ IOUT ≤ 3A 3

612

20 mV

AMS1085-3.3 VIN = 5V, 0 ≤ IOUT ≤ 3A 3

715

25 mV

AMS1085-3.5 VIN = 5.25V, 0 ≤ IOUT ≤ 3A 3

615

25 mV

AMS1085-5.0 VIN = 8V, 0 ≤ IOUT ≤ 3A 5

10 20

35 mV

Dropout Voltage

(VIN - VOUT)AMS1085/-1.5/-2.5/-2.85/

-3.0/-3.3/-3.5/-5.0 ∆VOUT , ∆VREF = 1%, IOUT = 3 A (Note 4) 1.3 1.5 V

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

AMS1085

ELECTRICAL CHARACTERISTICS

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

Parameter Device Conditions Min Typ Max Units

Current Limit AMS1085/-1.5/-2.5/-2.85/

-3.0/-3.3/-3.5/-5.0 (VIN - VOUT) = 5V 3.00 3.50 4.00 A

Minimum Load

Current AMS1085 (VIN - VOUT) = 12V (Note 5) 5 10 mA

Quiescent Current AMS1085/-1.5/-2.5/-2.85/

-3.0/-3.3/-3.5/-5.0 VIN ≤ 12V 5 10 mA

Ripple Rejection AMS1085 f =120Hz , COUT = 25µF Tantalum, IOUT = 3A,

(VIN-VOUT ) = 3V, CADJ =25µF60 75 dB

AMS1085-1.5 f =120Hz , COUT = 25µF Tantalum, IOUT = 3A,

VIN = 4.5V 60 72 dB

AMS1085-2.5 f =120Hz , COUT = 25µF Tantalum, IOUT = 3A,

VIN = 5.5V 60 72 dB

AMS1085-2.85 f =120Hz , COUT = 25µF Tantalum, IOUT = 3A,

VIN = 6V 60 72 dB

AMS1085-3.0 f =120Hz , COUT = 25µF Tantalum, IOUT = 3A

VIN = 6V 60 72 dB

AMS1085-3.3 f =120Hz , COUT = 25µF Tantalum, IOUT = 3A

VIN = 6.3V 60 72 dB

AMS1085-3.5 f =120Hz , COUT = 25µF Tantalum, IOUT = 3A

VIN = 6.5V 60 72 dB

AMS1085-5.0 f =120Hz , COUT = 25µF Tantalum, IOUT = 3A

VIN = 8V 60 68 dB

Thermal Regulation AMS1085 TA = 25°C, 30ms pulse 0.008 0.04 %W

Adjust Pin Current AMS1085 10mA ≤ IOUT ≤ 3A , 1.5V≤ (VIN - VOUT) ≤ 12V 55 120 µA

µA

Adjust Pin Current

Change AMS1085 10mA ≤ IOUT ≤ 3A , 1.5V≤ (VIN - VOUT) ≤12V 0.2 5µA

Temperature Stability 0.5 %

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

RMS Output Noise

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

Thermal Resistance

Junction-to-Case M Package: Control Circuitry/ Power Transistor

T Package: Control Circuitry/ Power Transistor

1.5/4.0

1.5/4.0 °C/W

°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 15W. 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 (VIN - VOUT) = 12V the device is guaranteed to

regulate if the output current is greater than 10mA.

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

AMS1085

APPLICATION HINTS

The AMS1085 series of adjustable and fixed regulators are easy

to use and have all the protection features expected in high

performance voltage regulators: short circuit protection and

thermal shutdown.

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 AMS1085 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 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 AMS1085 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

AMS1085 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 AMS1085 is used. Normal

power supply cycling or even plugging and unplugging in the

system will not generate current large enough to do any damage.

The adjustment pin can be driven on a transient basis ±25V, with

respect to the output without any device degradation. As with any

IC regulator, none the protection circuitry will be functional and

the internal transistors will break down if the maximum input to

output voltage differential is exceeded.

AMS1085

IN OUT

ADJ +COUT

150µF

VOUT

CADJ

10µF

VIN

Overload Recovery

When the power is first turned on, as the input voltage rises, the

output follows the input, permitting the regulator to start up into

heavy loads. During the start-up, as the input voltage is rising,

the input-to-output voltage differential remains small, allowing

the regulator to supply large output currents. A problem can occur

with a heavy output load when the input voltage is high and the

output voltage is low, when the removal of an output short will

not permit the output voltage to recover. The load line for such a

load may intersect two points on the output current curve. In this

case, there are two stable output operating points for the

regulator. With this double intersection, the power supply may

need to be cycled down to zero and brought up again to make the

output recover.

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

to120Ω) 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 25µF. At 10kHz only 0.22µF 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 ).

Output Voltage

The AMS1085 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.

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

AMS1085

APPLICATION HINTS

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.

AMS1085

IN OUT

ADJ R1

VOUT

VREF

VIN

IADJ

50µA

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

Figure 1. Basic Adjustable Regulator

Load Regulation

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

AMS1085 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

AMS1085

IN OUT

ADJ

R1*

R2*

VIN

PARASITIC

LINE RESISTANCE

*CONNECT R1 TO CASE

CONNECT R2 TO LOAD

Figure 2. Connections for Best Load Regulation

Connected as shown, R

P is

not multiplied by the divider ratio.

Using 16-gauge wire the parasitic line resistance is about 0.004Ω

per foot, translating to 4mV/ft at 1A load current. It is important

to keep the positive lead between regulator and load as short as

possible and use large wire or PC board traces.

Thermal Considerations

The AMS1085 series have internal power and thermal limiting

circuitry designed to protect the device under overload

conditions. However maximum junction temperature ratings

should not be exceeded under continuous normal load conditions.

Careful consideration must be given to all sources of thermal

resistance from junction to ambient, including junction-to-case,

case-to-heat sink interface and heat sink resistance itself. To

ensure safe operating temperatures and reflect more accurately

the device temperature, new thermal resistance specifications

have been developed. Unlike older regulators with a single

junction-to-case thermal resistance specification, the data section

for these new regulators provides a separate thermal resistance

and maximum junction temperature for both the Control Section

and the Power Transistor. Calculations for both temperatures

under certain conditions of ambient temperature and heat sink

resistance and to ensure that both thermal limits are met.

Junction-to-case thermal resistance is specified from the IC

junction to the bottom of the case directly below the die. This is

the lowest resistance path for the heat flow. In order to ensure the

best possible thermal flow from this area of the package to the

heat sink proper mounting is required. Thermal compound at the

case-to-heat sink interface is recommended. A thermally

conductive spacer can be used, if the case of the device must be

electrically isolated, but its added contribution to thermal

resistance has to be considered.

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

AMS1085

TYPICAL PERFORMANCE CHARACTERISTICS

-2.0

-1.0

1.0

2.0

-50 -25 0 25 50 75 100 125 150

TEMPERATURE (° C)

0 1 2 3 4

Dropout Voltage

-0.20

-0.15

-0.10

-0.05

0.05

0.10

-50 -25 0 25 50 75 100 125 150

02468 10 12

Short-Circuit Current

Load Regulation

-0.2

0.3

50 60 70 80 90100 110

0 100

-40

00.2 0.4 0.6 0.8 1.0

100

Temperature Stability

Ripple Rejection vs. Current

100 1k 10k 100k

Ripple Rejection

100

-0.3

-0.1

0.1

0.2

Load Transient Response

200

Line Transient Response

-60

-20

Maximum Power Dissipation*

120 130 140 150

TIME (µs) TIME (µs) CASE TEMPERATURE (° C)

*AS LIMITED BY MAXIMUM JUNCTION TEMPERATURE

POWER (W)

INPUT

DEVIATION (V) OUTPUT VOLTAGE

DEVIATION (mV)

LOAD

CURRENT (A) OUTPUT VOLTAGE

DEVIATION (V)

FREQUENCY (Hz)

RIPPLE REJECTION (dB)

OUTPUT CURRENT (0 TO IFULL LOAD )INPUT/OUTPUT DIFFERENTIAL (V)

SHORT-CIRCUIT CURRENT (A) OUTPUT VOLTAGE CHANGE (%)

TEMPERATURE (° C)

OUTPUT VOLTAGE DEVIATION (%)

OUTPUT CURRENT (A)

MINIMUM INPUT/OUTPUT

DIFFERENTIAL (V)

fR = 120Hz

VRIPPLE

≤

3VP-P

fR =20kHz

VRIPPLE

≤

0.5VP-P

IOUT=IFULL LOAD

(VIN-VOUT)

≥

VDROPOUT

VRIPPLE

≤

3VP-P VRIPPLE

≤

0.5VP-P

(VIN-VOUT)

≥

CADJ = 0

VOUT = 10V

IIN = 0.2A

CIN = 1

F TANTALUM

COUT = 10

F TANTALUM

VOUT = 10V

VIN = 13V

PRELOAD = 100mA

CIN = 1

COUT = 10

F TANTALUM

CADJ = 0

∆

I = 3A

TJ =150° C

TJ =25° C

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

AMS1085

TYPICAL PERFORMANCE CHARACTERISTICS (Continued)

-50 -25 025 50 75 125

100

0 2 4 6 8 10 12

14 100 150

Minimum Operating Current

(Adjustable only)

Adjust Pin Current

(Adjustable only)

ADJUST PIN CURRENT (µA)

TEMPERATURE (° C)INPUT/OUTPUT DIFFERENTIAL (V)

MINIMUM OPERATING CURRENT (mA)

TJ = 25° C

TJ = 150° C

PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.

3 LEAD TO-220 PLASTIC PACKAGE (T)

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

AMS1085

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

AMS1085

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

TO-252 PLASTIC PACKAGE (D)

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°