Diodes AP1184 User Manual

AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

FIXED-MODE REGULATOR

Features

General Description

• 0.85V maximum dropout voltage at 4A load current

• Built-in Thermal shutdown

• Output current limiting

• Adjustable or fixed output voltage1.5V, 1.8V, 2.5V,

3.3V, 5.0V

• Fast transient response

• Good noise rejection

• Packages: TO220-5L and TO263-5L

• Lead Free Finish/ RoHS Complian (Note 1)

AP1184 is a 4A regulator with extremely low dropout voltage. This product is specifically designed to provide well regulated supply for applications requiring 2.8V or lower voltages from 3.3V ATX power supplies where high efficiency of the switch can be achieved without the cost and complexity associated with switching regulator. One such application is the new graphic chipsets that requires anywhere from 2.4V to 2.7V supply.

Ordering Information

XX

Vout

Package

K5 : TO263-5L T5 : TO220-5L

AP1184

Blank : Adj 15 = 1.5V 18 = 1.8V 25 = 2.5V 33 = 3.3V 50 = 5.0V

Device

AP1184K5XXL-U K5 TO263-5L 50 -U NA NA

Lead-free

AP1184K5XXL-13 K5 TO263-5L NA NA 800/Tape & Reel -13

Lead-free

AP1184T5XXL-U T5 TO220-5L 50 -U NA NA

Lead-free

Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes.

2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at http://www.diodes.com/datasheets/ap02001.pdf

Package

Code

Packaging

(Note 2)

.

L X

XX

-

Quantity

-

Lead Free

L : Lead Free

Tube 13” Tape and Reel

Part Number

Suffix

Packing

U : Tube

13 : Tape & Reel

Quantity

Part Number

Suffix

AP1184 Rev. 5 1 of 12 SEPTEMBER 2008

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A

Pin Assignments

FRONT VIEW

5 4 3

2 1

Tab is Vout

AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

FIXED-MODE REGULATOR

Vin Vctrl Vout

Adj(GND)

Vsense

FRONT VIEW

5

4 3

2 1

Tab is Vout

Vin Vctrl Vout Adj(GND) Vsense

TO263-5L

Pin Descriptions

Pin Numbers with standard type are for TO220-5L, TO263-5L packages.

Name I/O Description

Adj

(GND)

resistor divider from this pin to the Vout pin and ground sets the output voltage. (GND

only for fixed mode)

This pin is the positive side of the reference that allows remote load sensing to achieve

Vsense I

excellent load regulation. A minimum of 10uF capacitor must be connected from this pin to ground to insure stability.

The input of the regulator. Typically a large storage capacitor is connected from this pin

Vin I

to ground to insure that the input voltage does not sag below the minimum dropout voltage during the load transient response. This pin must always be higher than Vout in order for the device to regulate. This pin is the supply pin for the internal control circuit as well as the base drive for the

Vctrl I

pass transistor. This pin must always be higher than the Vout pi n in ord er to regu late the device. A minimum of 100uF capacitor must be connected from this pin to ground to insure stability.

Vout O

The output of the regulator. A minimum of 100uF capacitor must be connected from this pin to ground to insure stability.

Block Diagram

TO220-5L

Vin

Vctrl

CURRENT

LIMIT

THERMAL

SHUTDOWN

+

-

1.25V

+

-

Vout

Vsense

Adj

AP1184 Rev. 5 2 of 12 SEPTEMBER 2008

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AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

Typical Application Circuit

(1) Adjustable Regulator

3.3V

FIXED-MODE REGULATOR

5V

470µF

Vctrl

Vout

Vsense

Tab is Vout

(2) 3.3V to 2.5V Fixed Mode Regulator

3.3V

470µF

Vctrl

Vout

GND

Vsense

Vin

Adj

Vin

V:Note +×=

OUT

V

REF

R1

R2

121

1(

470µF

Ω

2.5V/ 4A

470µF

R

2

)

R

1

5V

470µF

2.5V/ 4A

470µF

Tab is Vout

Absolute Maximum Ratings

Symbol Parameter Rating Unit

VIN Input Voltage 16 V

V

Control Input voltage 18 V

ctrl

PD Power dissipation Internally limited TST Storage temperature Range -65 to +150 TOP Operation Junction Temperature Range 0 to +125

AP1184 Rev. 5 3 of 12 SEPTEMBER 2008

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o

C

o

C

AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

FIXED-MODE REGULATOR

Electrical Characteristics (Under Operating Conditions)

Unless otherwise specified, these specifications apply over, Cin = 1uF, C V

out

= V

sense

Sym. Parameter Test Condition Min Typ. Max Unit

=10mA, TA = 25oC, (Vin-V

I

V

Reference Voltage AP1184-Adj

REF

Line Regulation AP1184-XXX

AP1184-1.5 AP1184-1.8

V

Output Voltage

out

AP1184-2.5 AP1184-3.3 AP1184-5.0 AP1184-Adj AP1184-1.5

Load

Regulation

AP1184-1.8 AP1184-2.5 AP1184-3.3 AP1184-5.0

= 0V for all conditions below.

V

adj

Dropout Voltage

–V

(V

)

ctrl

out

Dropout Voltage (Vin – V

out

)

Current Limit

Minimum Load Current

= 2.05V, Io = 1.5A

V

in

V

= 2.05V, Io = 3A

in

= 2.05V, Io = 4A

V

in

V

= 0V for all conditions below.

adj

V

= 2.75V, Io = 1.5A

ctrl

= 2.75V, Io = 3A

V

ctrl

V

=2.75V, Io =4A

ctrl

V

= 2.75V, Vin = 2.05V, ΔVo = 100mV, V

ctrl

V

= 5V, Vin = 3.3V, V

ctrl

Thermal Regulation 30mS Pulse 0.01 0.02 %/W Ripple Rejection

Vctrl = 5V, Vin = 5V, Io = 4A, Vadj = 0V, Tj = 25, Vripple =1Vpp at 120Hz Vadj = 0V for all conditions below.

Control Pin Current

Vctrl = 2.75V, Vin = 2.05V, Io = 1.5A Vctrl = 2.75V, Vin = 2.05V, Io = 3A Vctrl = 2.75V, Vin = 2.05V, Io = 4A

o

= VIN+1V

V

ctrl

= 10mA, V

I

O

V

= VIN+1V

ctrl

= 10mA, TA = 25oC, 2.2VVIN12V

I

OUT

= VIN+1V

V

ctrl

= 10mA, TA = 25oC, 2.5VVIN12V

I

OUT

V

= VIN+1V

ctrl

= 10mA, TA = 25oC, 3.2VVIN12V

I

OUT

= VIN+1V

V

ctrl

= 10mA, TA = 25oC, 4.0VVIN12V

I

OUT

V

= VIN+1V

ctrl

= 10mA, TA = 25oC, 5.7VVIN12V

I

OUT

= VIN+1V

V

ctrl

0mA<Io<4A, T (V

- V

IN

= 3V, 0mA<Io<4A, TA = 25oC

V

IN

= 4V

V

ctrl

= 3.3V, 0mA<Io<4A, TA = 25oC

V

IN

V

= 4.3V

ctrl

= 4V, 0mA<Io<4A, TA = 25oC

V

IN

= 5V

V

ctrl

= 5V, 0mA<Io<4A, TA = 25oC

V

IN

V

= 6V

ctrl

= 8V, 0mA<Io<4A, TA = 25oC

V

IN

V

= 9V

ctrl

OUT

A

) =2V ,V

OUT

= 0V 5 10 mA

adj

= 10uF, and Tj = 0 to 150oC. Typical value refer to TA = 25oC.

out

) = 0.7V,

out

+0.7V<VIN<12V, TA = 25oC

1.225 1.250 1.275 V

0.2 %

1.470 1.500 1.530 V

1.764 1.800 1.836 V

2.450 2.500 2.550 V

3.235 3.300 3.365 V

4.900 5.000 5.100 V

= 25oC

= VIN + 1V

ctrl

1 % 12 15 mV 15 18 mV 20 25 mV 26 33 mV 40 50 mV

1.10

0.26

0.50

0.70

adj

= 0V

4.2 A

60 70 dB

6 30 33

1.15

1.18

1.25

0.38

0.60

0.85

25 60 70

V

mA

V

AP1184 Rev. 5 4 of 12 SEPTEMBER 2008

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AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

FIXED-MODE REGULATOR

Electrical Characteristics (Continued)

Unless otherwise specified, these specifications apply over, Cin = 1uF, C V

= V

t

ou

sense

.

Sym. Parameter Test Condition Min Typ. Max Unit

I

adj

Adjust Pin Current

= 2.75V, Vin = 2.05,V

V

ctrl

adjj

= 0

= 10uF, and Tj = 0 to 150oC. Typical value refer to TA = 25oC.

out

50 150 µA

θ

Thermal Resistance

JA

Junction-to-Ambient

θ

Thermal Resistance

JC

Junction-to-Case

Notes: 3. AP1184-ADJ incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the allowable maximum junction temperature.

4. Test conditions for TO263-5L : Devise mounted on 2oz copper, minimum recommended pad layout , FR-4 PCB.

5. Test conditions for TO220-5L : with copper area of approximately 3in

TO263-5L: Control Circuitry/Power Transistor (Note 4) TO220-5L: Control Circuitry/Power Transistor (Note 5)

2

, 1oz.

61 31

7 5

O

C/W

O

C/W

O

C/W

O

C/W

Package Max Pd. Remarks

TO263-5L/TO220-5L 2.4W~4.4W With heat sink or amount of copper board needed.

Functional Descriptions

Introduction

The AP1184 regulator is a 5 terminal device designed specifically to provide extremely low dropout voltages comparable to the PNP type without the disadvantage of the extra power dissipation due to the base current associated with PNP regulators. This is done by bringing out the control pin of the regulator that provides the base current to the power NPN and connecting it to a voltage that is greater than the

voltage present at the motherboard with an ATX style power supply that provides 5V and 3.3V to the board. One such application is the new graphic chip sets that require anywhere from 2.4V to 2.7V supply. The AP1184 can easily be programmed with the addition of two external resistors to any voltages within the range of 1.25V to 15.5V. Another major requirement of these graphic chips is the need to switch the load current from zero to several amps in tens of nanoseconds at the processor pins, which translates to an approximately 300 to 500ns of current step at the regulator. In addition, the output voltage tolerances are also extremely tight and they include the transient response as part of the specification.

The AP1184 is specifically designed to meet the fast current transient needs as well as providing an accurate initial voltage, reducing the overall system cost with the need for fewer number of output capacitors. Another feature of the device is its true remote sensing capability that allows accurate voltage setting at the load rather than at the device.

Output Voltage Setting

The AP1184-ADJ can be programmed to any voltages in the range of 1.25V to 15.5V with the addition of R1 and R2 external resistors according to the following formula:

V

pin. This flexibility makes the AP1184 ideal for applications where dual inputs are available such as a computer

in

AP1184 Rev. 5 5 of 12 SEPTEMBER 2008

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AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

Functional Descriptions (Continued)

Vout = Vref (1+R2/R1) + Iadj * R2 where : Vref = 1.25V & Iadj=50uA Typically

FIXED-MODE REGULATOR

Vin

Vctrl

AP1184-ADJ

Adj

Iadj=50uA

Vsense

Vref

R1+

R2+

Vout

The AP1184-ADJ keeps a constant 1.25V between the Vsense pin and the Adj pin. By placing a resistor R1 across these two pins and connecting the Vsense and Vout pin together, a constant current flows through R1, adding to the Iadj current and into the R2 resistor producing a voltage equal to the (1.25/R1)*R2 + Iadj*R2. This voltage is then added to the 1.2 5V to set the output voltage. This is summarized in the above equation. Since the minimum load current requirement of the AP1184-ADJ is 10mA, R1 is ty pically selected to be a 121Ω resistor so that it automatically satisfies this condition. Notice that since the Iadj is typically in the range of 50uA it only adds a small error to the output voltage and should be considered when very precise output voltage setting is required.

Load Regulation

Since the AP1184 has separate pins for the output (Vout) and the sense (Vsense), it is ideal for providing true remote sensing of the output voltage at the load. This means that the voltage drops due to parasitic resistance such as PCB traces between the regulator and the load are compensated for using remote sensing. Figure following shows a typical application of the AP1184-ADJ with remote sensing.

Vin

Vctrl

Vin

Vctrl

AP1184-ADJ

Adj

Vout

Vsense

R1

R

L

R2

Stability

The AP1184-XXX requires the use of an output capacitor as part of the frequency compensation in order to make the regulator stable. Typical designs for the microprocessor applications use standard electrolytic capacitors with typical ESR in the range of 50 to 100mΩ and an output capacitance of 100uF to 1000uF. Fortunately as the capacitance increases, the ESR dec reases resulting in a fixed RC time constant. The AP1184-XXX takes advantage of the phenomena in making the overall regulator loop stable. For most applications a minimum of 100uF aluminum electrolytic capacitor insures both stability and good transient response.

Thermal Design

The AP1184-XXX incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the allowable maximum junction temperature. Although this device can operate with junction temperatures in the range of 150 recommended that the selected heat sink be chosen such that during maximum continuous load operation, the junction temperature is kept below this number. The example below shows the steps in selecting the proper surface mount package.

o

C, it is

AP1184 Rev. 5 6 of 12 SEPTEMBER 2008

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AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

FIXED-MODE REGULATOR

Functional Descriptions (Continued)

Assuming, the following conditions:

= 2.5V

V

out

V

= 3.3V

in

V

= 5V

ctrl

I

= 2A DC Avg.

out

Calculate the maximum power dissipation using the following equation:

= I

P P

Using table below select the proper package and the amount of copper board needed.

* ( Vin - V

d

out

= 2 * (3.3-2.5) + (2/60) * (5-2.5) = 1.68W

d

Package Copper Area θ

TO263-5L Pad Size-1.4”X1.4” 25-45 2.4W-4.4W 2.0W-3.6W

Notes: 6. Above table is based on the maximum junction temperature of 135oC.

As shown in the above table, any of the two packages will do the job.

out

) + ( I

/60) * ( V

out

ctrl

- V

)

out

(oC/W) Max Pd (TA = 25oC) Max Pd (TA = 45oC)

JA

AP1184 Rev. 5 7 of 12 SEPTEMBER 2008

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

Performance Characteristics

1200

Vpower = 2.05 V

1100

1000

Tj = 20 oC

900

Tj = 120 oC

Vcontrol Dropout Voltage (mV)

800

0

V

control

0.5

1.5

1.0 Output Current (A)

2.0

2.5 3.0 3.5 4.0

Dropout Voltage vs Output Current

FIXED-MODE REGULATOR

800

Vcontrol = 2.75 V

750 700 650 600 550 500 450 400 350 300 250 200 150

Vpower Dropout Voltage (mV)

100

50

0

V

power

0.5

Dropout Voltage vs Output Current

Tj = 120 oC

1.0

1.5 2.0

Output Current (A)

AP1184

Tj = 20 oC

2.5

3.0 3.5 4.0

1. 253

1. 252

1. 251

1. 250

1. 249

Reference Voltage (V)

1. 248

1. 247

20

0

40 60 80 100 120

Junction Temperature (oC)

Reference Voltage vs Junction Temperature

0. 15

0. 14

0. 12

0. 10

0. 08

0. 06

0. 04

Load Regulation (%)

0. 02

0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

0

Load Regulation vs Output Current

Tj = 120 oC

Tj = 20 oC

Output Current (A)

AP1184 Rev. 5 8 of 12 SEPTEMBER 2008

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

Performance Characteristic (Continued)

AP1184

FIXED-MODE REGULATOR

Transient Response

V

CONTROL

= 3.3V

V

POWER

= 2.5V

V

OUT

C

CONTROL

= 100uF

C

POWER

C

= 0.1uF

ADJ

= 470uF

C

OUT

I

LOAD

10mA to 4A

= 5.0V

=10uF

AP1184 Rev. 5 9 of 12 SEPTEMBER 2008

Marking Information

(1) TO263-5L

1184-XX: Voltage

1184: Adj

1184-15 : 1.5V 1184-18 : 1.8V 1184-25 : 2.5V 1184-33 : 3.3V

1184-50 : 5.0V

AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

FIXED-MODE REGULATOR

( Top View )

Logo

1184-XX YY WW

X

L : Lead Free

ID code

Xth week : 01~52 Year :

"07" = 2007 "08" = 2008

~

(2) TO220-5L

1184-XX: Voltage

1184: Adj 1184-15: 1.5V 1184-18: 1.8V 1184-25: 2.5V 1184-33: 3.3V 1184-50: 5.0V

( Top view )

1184-XX YY WW X X

Logo L : Lead Free Package

ID code Xth week: 01~52

Year:

"07" = 2007 "08" = 2008

~

AP1184 Rev. 5 10 of 12 SEPTEMBER 2008

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

Package Information (All Dimensions in mm)

(1) Package Type: TO263-5L

AP1184

FIXED-MODE REGULATOR

(2) Package Type: TO220-5L

AP1184 Rev. 5 11 of 12 SEPTEMBER 2008

AP1184

4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE OR

FIXED-MODE REGULATOR

IMPORTANT NOTICE

Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither does it convey any license under its patent rights, nor the rights of others. The user of products in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on our website, harmless against all damages.

LIFE SUPPORT

Diodes Incorporated products are not authorized for use as critical components in life support devices or systems without the expressed written approval of the President of Diodes Incorporated.

AP1184 Rev. 5 12 of 12 SEPTEMBER 2008