AME AME1085DCBT, AME1085AMCT, AME1085ACDT-3, AME1085ACDT, AME1085ACBT, AME1085DMCT, AME1085DCDT-3, AME1085DCDT Datasheet

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Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

n General Description

The AME1085 is a 3A low-dropout positive voltage regulator. It is available in fixed and adjustable output voltage versions. Overcurrent and thermal protection are integrated onto the chip. Output current will limit as it reaches the pre-set current or temperature limit. At full rated output current the dropout voltage is 1.4V (max.). AME1085 series regulators provide excellent regulation over line, load and temperature variations.

n Key Features

lLow dropout voltage 1.2V typically at 3A

lAdjustable or 3.3V fixed voltage

lLine regulation typically 0.015%

lLoad regulation typically 0.05%

lAdjust pin (ADJ) current less than 90υA

lOvercurrent protection

lThermal protection

lAvailable in TO-220, TO-263, TO-252

n Applications

lHigh Efficiency Linear Regulators

lPost Regulators for Switching Supplies

l5V to 3.3V Voltage Converter

lBattery Charger

n Functional Block Diagram

Input

Current

Limiting

Amplifier

 

Thermal

Output

 

Protection

 

 

 

 

Error

Amp. Bandgap ADJ/GN D

Reference

Figure 1

n Typical Application

 

 

 

 

AME1085

 

 

 

 

 

 

 

V IN

V O U T

 

 

 

 

 

 

 

 

GND

 

 

 

 

 

 

 

 

 

 

 

 

4.75V to 5.25V

 

 

10μF Tan

 

 

 

10μF Tan Load

 

 

 

 

 

 

 

 

 

Figure 2

1

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

n Pin Configuration

To-263 Front View

To-263-2 Front View

AME 1085

1 2 3

AME 1085

1 2 3

A D J / G N D V O U T V IN

A D J / G N D V O U T V IN

To-252-2 Front View

TO-252-2 Front view

 

 

 

 

AME1085

 

AME 1085

1

2

3

1

2

 

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ADJ/

VOUT

VIN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A D J / G N D V O U T

V IN

 

GND

 

 

 

 

 

 

 

 

 

 

 

 

2

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

n Ordering Information

Part Number

Marking

Output Voltage

Package

 

 

 

 

 

AME1085

 

 

AME1085ACBT

ACBT

ADJ

TO-220

 

YYWW

 

 

 

 

 

 

 

AME1085

 

 

AME1085DCBT

DCBT

3.3

TO-220

 

YYWW

 

 

 

 

 

 

 

AME1085

 

 

AME1085ACDT-3

ACDT-3

ADJ

TO-263-3

 

YYWW

 

 

 

 

 

 

 

AME1085

 

 

AME1085DCDT-3

DCDT-3

3.3

TO-263-3

 

YYWW

 

 

 

 

 

 

 

AME1085

 

 

AME1085ACDT

ACDT

ADJ

TO-263-2

 

YYWW

 

 

 

 

 

 

 

AME1085

 

 

AME1085DCDT

DCDT

3.3

TO-263-2

 

YYWW

 

 

 

 

 

 

 

AME1085

 

 

AME1085AMCT

AMCT

ADJ

TO-252-2

 

YYWW

 

 

 

 

 

 

 

AME1085

 

 

AME1085MCT*

MCT

3.3

TO-252-2

 

YYWW

 

 

* This differs from our standard part numbering scheme due to historical precedent

n Absolute Maximum Ratings

Parameter

 

Symbol

Maximum

Units

Input Voltage

 

VIN

7

V

Thermal Resistance

 

TO-220

 

2.5

 

 

TO-263

θJC

2.5

 

(Junction to Case)

 

 

 

TO-252

 

15

0C/W

 

 

 

Thermal Resistance

 

TO-220

 

50

 

 

TO-263

θJA

60

 

(Junction to Ambient)

 

 

 

TO-252

 

90

 

 

 

 

 

Operating Junction Temperature Range

 

TJ

0 to 125

 

Storage Temperature Range

 

TSTG

-65 to 150

0C

Lead Temperature ( 10 sec )

 

TLEAD

260

 

3

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

n Electrical Characteristics

AME1085AXXX

 

 

Parameter

Symbol

 

 

Test Conditions

 

Min.

Typ.

Max.

Units

 

Reference voltage

VREF

VIN = 5V

TJ =250C

1.238

1.250

1.262

V

 

(adjustable voltage)

IO = 10mA

Over temp.

1.225

1.275

 

 

 

 

 

 

 

 

V

 

= 2.75 - 7V

T =250C

-

0.015

0.2

 

 

Line regulation

RegLINE

IN

 

J

 

 

 

%

 

I

= 10mA

Over temp.

-

0.035

0.2

 

 

 

 

O

 

 

 

 

 

 

 

 

Load regulation

RegLOAD

VIN = 5V

TJ =250C

-

0.05

0.3

%

 

I

= 10mA - 3A

Over temp.

-

0.2

0.4

 

 

 

 

O

 

 

 

 

 

 

 

 

Dropout voltage

VD

VIN = 2.75 - 7V

TJ =250C

-

1.2

1.4

V

 

VOUT,

VREF = 1%

IO = 10mA - 3A

Over temp.

-

1.3

-

 

 

 

 

Current limit

IS

VIN = 2.75 - 7V, Over temp.

 

3.0

-

-

A

 

Temperature Coefficient

TC

VIN = 2.75 - 7V, IO = 10mA - 3A

-

0.005

-

%/OC

 

Temperature stability

TS

VIN = 5V, IO = 500mA, Over temp.

-

0.5

-

%

 

Minimum load current

IO

VIN = 5V

 

-

5

10

mA

 

RMS output noise

VN

TJ =250C

 

-

0.003

-

%V0

 

Ripple rejection ratio

RA

VIN = 5V, IO = 3A, Over temp.

60

72

-

dB

AME1085DXXX

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter

Symbol

 

 

Test Conditions

 

Min.

Typ.

Max.

Units

 

Output voltage

Vo

VIN = 5V

TJ =250C

3.267

3.300

3.333

V

 

(fixed voltage)

IO = 0A

Over temp.

3.234

3.366

 

 

 

 

 

 

 

 

V

 

=4.5 - 7V

T =250C

-

0.015

0.2

 

 

Line regulation

RegLINE

IN

 

J

 

 

 

%

 

I

= 0A

Over temp.

-

0.035

0.2

 

 

 

 

O

 

 

 

 

 

 

 

 

Load regulation

RegLOAD

VIN = 5V

TJ =250C

-

0.05

0.3

%

 

I

= 0A - 3A

Over temp.

-

0.2

0.4

 

 

 

 

O

 

 

 

 

 

 

 

 

Dropout voltage

VD

VIN = 4.5 - 7V

TJ =250C

-

1.2

1.4

V

 

VOUT,

VREF = 1%

IO = 0A - 3A

Over temp.

-

1.3

-

 

 

 

 

Current limit

IS

VIN = 4.5 - 7V, Over temp.

 

3.0

-

-

A

 

Quiescent current

IQ

VIN = 5V, Io=0A - 3A, Over temp.

-

12

13

mA

 

(fixed model)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Temperature Coefficient

TC

VIN = 4.5 - 7V, IO = 0A - 3A

 

-

0.005

-

%/0C

 

Temperature stability

TS

VIN = 5V, IO = 500mA, Over temp.

-

0.5

-

%

 

RMS output noise

VN

TJ =250C

 

-

0.003

-

%V0

 

Ripple rejection ratio

RA

VIN = 5V, IO = 3A, Over temp.

60

72

-

dB

4

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

nApplication Description

1.Output voltage adjustment

Like most regulators, the AME1085 regulates the output by comparing the output voltage to an

internally generated reference voltage. On the adjustable version, the VREF is available externally as 1.25V between VOUT and ADJ. The voltage ratio formed by R1 and R2 should be set to conduct 10mA (minimum output load). The output voltage is given by the following equation:

VOUT = VREF ( 1 + R2 ) + IADJ x R2 R1

On fixed versions of AME1085, the voltage divider is provided internally.

VIN

 

IN

 

 

O U T

 

VO U T

C 1

 

 

 

ADJ

 

VREF

R1

 

 

 

 

 

 

 

 

IADJ

 

 

 

 

 

 

 

50μA

 

 

 

 

 

 

 

 

 

 

 

 

 

R2

V

O U T

= V

REF

(1+

R2 ) + I

ADJ

x R2

 

 

 

 

R1

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3

 

 

VIN

3.Current limit protection

AME1085 is protected against overload conditions. Current protection is triggered at typically 4.5A.

4.Stability and load regulation

AME1085 requires a capacitor from VOUT to GND to provide compensation feedback to the

internal gain stage. This is to ensure stability at the output terminal. Typically, a 10μF tantalum or 50μF aluminum electrolytic is sufficient.

Note: It is important that the ESR for this capacitor does not exceed 0.5Ω.

The output capacitor dose not have a theoreti-

cal upper limit and increasing its value will increase stability. COUT = 100μF or more is typical for high current regulator design.

For the adjustable version, the best load regulation is accomplished when the top of the resistor divider (R1) is connected directly to the output pin of the AME1085. When so con-

nected, RP is not multiplied by the divider ratio. For fixed output versions, the top of R1 is internally connected to the output and ground pin can be connected to low side of the load.

R P

Parasitic

Line Resistance

IN O U T

ADJ

2.Thermal protection

AME1085 has thermal protection which limits junction temperature to 150OC. However, de-

vice

functionality is only guaranteed to a maxi-

mum

junction temperature of +125OC.

The power dissipation and junction temperature for AME1085 in TO-220 package are given by

R1

R L

(Connect R1 to case)

R2

PD = (VIN - VOUT) x IOUT

 

 

 

 

 

 

 

Connect

 

 

 

 

 

 

 

 

 

 

 

 

 

 

x θJA)

 

 

 

TJUNCTION = TAMBIENT + ( PD

 

 

 

 

 

 

R2 to load

 

 

 

 

 

 

 

 

Note: TJUNCTION must not exceed 125OC

Figure 4

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