A1085S3VR-50 [AITSEMI]

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR;


型号：	A1085S3VR-50
厂家：	AiT Semiconductor
描述：	3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR
文件：	总12页 (文件大小：616K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

DESCRIPTION

FEATURES

ꢀ

Provide Fixed Version and an Adjustable

Version, Output Value can be customized on

command.

The A1085 is a series of low dropout three terminal

regulators with a dropout of 1.3V at 3A load current.

Other than a fixed version (V_OUT=1.8V, 2.5V, 3.3V,

5V), The A1085 has an adjustable version, which

can set the output voltage with only two external

resistors.

ꢀ

Maximum Output Current: 3A

Output Voltage Accuracy within ±2%

Range of Operation Input Voltage: Max 15V

Line Regulation: 0.2% (Typ.)

Load Regulation: 0.4% (Typ.)

Environment Temperature: -50^oC~+140^oC

The A1085 offers thermal shut down and current

limit functions, to assure the stability of chip and

power system. And the A1085 uses trimming

technique to guarantee output voltage accuracy

within ±2%

Available in TO-252, TO-263-2 and TO-263-3

Package

APPLICATION

ꢀ

Power Management for Computer Mother

Board, Graphic Card

The A1085 is available in TO-252, TO-263-2 and

TO-263-3 package.

ꢀ

Battery Charger

Microprocessor Supply

Post Regulators for Switching Supplies

ORDERING INFORMATION

TYPICAL APPLICATION (Schematics 1)

Package Type

TO-252

Part Number

A1085DR-XX

A1085DVR-XX

A1085S2R-XX

A1085S2VR-XX

A1085S3R-XX

A1085S3VR-XX

TO-263-2

TO-263-3

Adjustable Version

XX: Output Voltage,

33 = 3.3V, 50 = 5V

ADJ: Adjustable

V_OUT= V_REFx (1 + R2 / R1) + I_ADJx R2

Note

R : Tape & Reel

V: Green Package

AiT provides all Pb free products

Suffix “V” means Green Package

Fixed Output Version

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 1 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

PIN DESCIPTION

Top View

TO-252

TO-263-2

TO-263-3

A1085DR-XX

GND

A1085DR-ADJ

A1085S2R-XX

A1085S2R-ADJ A1085S3R--XX A1085S3R-ADJ

ADJ

V_OUT

V_IN

GND

V_OUT

V_IN

ADJ

V_OUT

V_IN

GND

V_OUT

V_IN

ADJ

V_OUT

V_IN

V_OUT

V_IN

ABSOLUTE MAXIMUM RATINGS

Maximum Input Voltage

15V

Junction Temperature (T_J)

Environment Temperature (T_A)

Storage Temperature (Ts)

Lead Temperature and Time

150^oC

80^oC

-65^oC to 150^oC

260^oC, 10S

Stresses above may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at

these or any other conditions beyond those indicated in the Electrical Characteristics is not implied. Exposure to absolute maximum

rating conditions for extended periods may affect device reliability.

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 2 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

ELECTRICAL CHARACTERISTICS

Test Condition: C_IN=10uF, C_OUT=22uF, T_A= 25^oC, unless otherwise noted.

Symbol

V_REF

Parameter

Conditions

Min.

Typ.

Max.

1.262

1.275

Unit

_OUT=10mA, V_IN-V_OUT=3V

1.238 1.25

1.225 1.25

Reference Voltage

10mA≦I_OUT≦3A, 5V≦V_IN-V_OUT≦5V

A1085-1.8V

_OUT=0mA, V_IN=4.8V, T_J=25^oC

1.782 1.80

1.764 1.80

1.818

1.836

10mA≦I_OUT≦3A, 3.4V≦V_IN≦7V

A1085-2.5V

I_OUT=0mA, V_IN=4.8V, T_J=25^oC

10mA≦I_OUT≦3A, 4.1V≦V_IN≦7V

A1085-3.3V

I_OUT=0mA, V_IN=6.3V, T_J=25^oC

10mA≦I_OUT≦3A, 4.9V≦V_IN≦8V

A1085-5.0V

I_OUT=0mA, V_IN=8.0V, T_J=25^oC

10mA≦I_OUT≦3A, 6.6V≦V_IN≦10V

A1085-ADJ

2.475 2.50

2.450 2.50

2.525

2.550

V_OUT

Output Voltage

3.267

3.234

3.3

3.333

3.366

4.95

4.90

5.0

5.05

5.10

_OUT=10mA, 2.85V≦V_IN≦10V

0.035

0.2

A1085-1.8V

I_OUT=10mA, 3.4V≦V_IN≦10V

A1085-2.5V

Line Regulation

(Note1)

ΔV_OUT

I_OUT=10mA, 4.9V≦V_IN≦10V

A1085-5.0V

I_OUT=10mA, 6.6V≦V_IN≦10V

A1085-ADJ

V_IN-V_OUT=3V, 10mA≦I_OUT≦3A

A1085-1.8V

0.2

0.4

V_IN-V_OUT=3V, 0≦I_OUT≦3A

A1085-2.5V

Load Regulation

(Note1, 2)

ΔV_OOT

V_IN-V_OUT=3V, 0≦I_OUT≦3A

A1085-3.3V

V_IN-V_OUT=3V, 0≦I_OUT≦3A

A1085-5.0V

V_IN-V_OUT=3V, 0≦I_OUT≦3A

Dropout Voltage (Note3)

Current Limit

V_IN-V_OUT

I_LIMIT

ΔV_OUT, ΔV_REF=1%, I_OUT=3A

V_IN-V_OUT=3V, T_J=25^oC

1.3

1.5

3.2

4.5

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 3 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

Symbol

Parameter

Conditions

Min.

Typ.

Max.

Unit

Minimum Load Current (Note 4)

A1085-ADJ

V_IN=10V

Quiescent Current

Adjust Pin Current

I_ADJ

V_IN=4.25V, I_OUT=10mA

110

F=120Hz, C_OUT=25uF (Tan)

I_OUT=3A, V_IN-V_OUT=3V

Ripple Rejection

Adjust Pin Current

Change

Temperature Stability

Thermal Resistance

Junction to Case

10mA≦I_OUT≦3A, 1.5V≦V_IN≦6V

0.2

I_CHANGE

I_OUT=10mA, V_IN-V_OUT=1.5V

TO-252

0.5

12.5

θ_JC

^oC/W

TO-263-2 and TO-263-3

Note 1: The parameters of Line Regulation and Load Regulation are tested under constant junction temperature.

Note 2: When I_OUTvaries between 0~3A, V_IN-V_OUTvaries between 1.5V~6V under constant junction temperature, the parameter is

satisfied the criteria in above mentioned. If temperature varies between -50^oC≦T_A≦140^oC, needs output current to be larger

than 10mA to satisfy the criteria.

Note 3: Dropout Voltage is specified over I_OUT=3A and the following testing conditions:

First step is to find out the V_OUTValue (V_OUT1), when V_IN1= V_OUT+1.5V,

Second step is to decrease V_IN(V_IN2) until V_OUTvalue is equal to 99% x V_OUT1(V_OUT2). V_DROPOUT= V_IN2- V_OUT2

Note 4: Minimum Load Current is defined as the minimum output current required to maintain regulation.

When 1.5V≦V_IN-V_OUT≦6V, the device is guaranteed to regulate if the output current is greater than 10mA.

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 4 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

TYPICAL PERFORMANCE CHARACTERISTICS

1.Dropout Voltage vs. Output Current

3.Reference Voltage vs. Thermal Protection

5.Load Transient Response

2.Reference Voltage vs. Temperature

4.Output Voltage vs. Output Current

6. Line Transient Response

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 5 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

BLOCK DIAGRAM

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 6 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

DETAILED INFORMATION

The A1085 is a series of low dropout voltage, three terminal regulators which application circuit of fixed

version only needs two capacitors and the adjustable version only needs two resistors and two capacitors to

work. It is composed of some modules including start-up circuit, bias circuit, band-gap, thermal shutdown,

current limit, power transistors and its driver circuit and so on.

Thermal Shutdown and Current Limit

The A1085 thermal shutdown and current limit modules can assure chip and its application system working

safety when the environment temperature is larger than 140^oC or output current is larger than 3.2A.

Stable Reference Output Voltage

The band-gap module provides stable reference voltage, whose temperature coefficient is compensated by

careful design considerations. The temperature coefficient is under 100ppm/^oC. And the accuracy of

output voltage is guaranteed by trimming technique.

Application Hints

See Schematic 1

1. Recommend 10uF Tan capacitor (C_IN) as bypass capacitor for all application circuit.

2. Recommend 22uF Tan capacitor (C_OUT) to assure circuit stability.

3. Using a bypass capacitor (C_ADJ) between the adjust terminal and ground can improve ripple rejection, this

bypass capacitor prevents ripple from being amplified as the output voltage is increase. The impedance

of C_ADJshould be less than the resistor’s (R1) which is normally in the range of 120Ω ~ 200Ω, the value of

C_ADJshould satisfy this equation: 2 x F_RIPPLEx ＜R1. Recommend using 10uF Tan capacitor.

Output Voltage of Adjustable Version

The A1085-ADJ adjustable version provides 1.25V reference voltage. Any output voltage between 1.25V ~

13.8V can be available by choosing two external resistors (connection method is shown in Schematic 1), R1

and R2 are the two external resistors.

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 7 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

Example

The output voltage of A1085-ADJ adjustable version satisfies this followed equation:

_OUT=V_REFx (1+R2/R1) + I_ADJx R2

We can ignore I_ADJbecause I_ADJ(about 50uA) is much less than the current of R1 (about 4mA).

The value of R1 should be in the range 120Ω ~ 200Ω to assure chip working normally without any load. To

assure the electrical performance showed in Table 1, the output than 4mA, the best working condition is to

assure that the output current exceeds 10mA.

(Schematic 1)

Adjustable Version

V_OUT=V_REFx (1+R2/R1) + I_ADJx R2

Fixed Output Version

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 8 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

PACKAGE INFORMATION

Dimension in TO-252 (Unit: mm)

Tape Dimension

Reel Dimension

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 9 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

Dimension in TO-263-2 (Unit: mm)

Tape Dimension

Reel Dimension

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 10 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

Dimension in TO-263-3 (Unit: mm)

Tape Dimension

Reel Dimension

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 11 -

A1085

AiT Semiconductor Inc.

www.ait-ic.com

3A LOW-DROPOUT POSITIVE VOLTAGE REGULATOR

THERMAL SHUTDOWN AND CURRENT LIMIT FUNCTIONS

IMPORTANT NOTICE

AiT Semiconductor Inc. (AiT) reserves the right to make changes to any its product, specifications, to

discountinue any integrated circuit product or service without notice, and advises its customers to obtain the

latest version of relevant information to verify, before placing orders, that the information being relied on is

current.

AiT Semiconductor Inc.'s integrated circuit products are not designed, intended, authorized, or warranted to

be suitable for use in life support applications, devices or systems or other critical applications. Use of AiT

products in such applications is understood to be fully at the risk of the customer.

As used herein may

In order to

involve potential risks of death, personal injury, or servere property, or environmental damage.

minimize risks associated with the customer's applications, the customer should provide adequate design and

operating safeguards.

AiT Semiconductor Inc. assumes to no liability to customer product design or application support. AiT

warrants the performance of its products of the specifications applicable at the time of sale.

REV1.2

-AUG 2006 RELEASED – SEP 2008 REVISED -

- 12 -

A1085S3VR-50 [AITSEMI]

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