PL317E3 - CYStech Electronics Corp.

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 1/9

PL317E3 CYStek Product Specification

Three Terminal Adjustable Output

Positive Voltage Regulators

PL317E3

The PL317E3 is an adjustable 3–terminal positive voltage regulator capable

of supplying in excess of 1.5 A over an output voltage range of 1.2 V to 37 V.

This voltage regulator is exceptionally easy to use and requires only two ex-

ternal resistors to set the output voltage. Further, it employs internal current

limiting, thermal shutdown and safe area compensation, making it essentially

blow–out proof.

The PL317E3 serves a wide variety of applications including local, on-card

regulation. This device can also be used to make a programmable output regu-

lator, or by connecting a fixed resistor between the adjustment and output, the

PL317E3 can be used as a precision current regulator.

 Output Current in Excess of 1.5 A

 Output Adjustable between 1.2 V and 37 V

 Internal Thermal Overload Protection

 Internal Short Circuit Current Limiting Constant with Temperature

 Output Transistor Safe–Area Compensation

 Floating Operation for High Voltage Applications

 Eliminates Stocking many Fixed Voltages

Standard Application

+ +

PL317

R1

R2

CoutCin

Vin Vout

Maximum Ratings

Rating Symbol Value Unit

Input-Output Voltage Differential VI-VO 40 V

Power Dissipation

TA=25℃

Thermal Resistance, Junction-to-Ambient

Thermal Resistance, Junction-to-Case

PD

JA

JC

Internally Limited

65

5.0

W

℃/W

Operating Junction Temperature Range TJ -40 to +125 ℃

Storage Temperature Range Tstg -65 to +150 ℃

TO-220AB

1.0µF 0.1µF

＊Cin is required if regulator is located an appreciate

distance from power supply filter.

＊＊Cout is not needed for stability, however, it does

improve transient response.

Vout=1.25(1+R2/R1)+IAdjR2

Since IAdj is controlled to less than 100 µA, the

error associated with this term is negligible in

most applications.

IAdj

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 2/9

PL317E3 CYStek Product Specification

Electrical Characteristics(VI-VO=5V,IO=0.5A,TJ=0 to 125℃, unless otherwise noted)

Characteristics Symbol Conditions Min Typ Max Unit

Line Regulation(Note 1) Reg line TA=25℃,3.0VVI-VO40V - 0.01 0.04 %/V

Load Regulation(Note 1) Reg

load TA=25℃,10mAIO1.5A

VO5.0V

VO5.0V

-

5.0

0.1

25

0.5

mV

%VO

Thermal Regulation(Note 4) Reg therm TA=25℃, 20ms pulse - 0.03 0.07 %VO/W

Adjust Pin Current IAdj - 50 100 µA

Adjust Pin Current Change IAdj 2.5VVI-VO40V,10mAIL1.5A

PD20W

- 0.2 5.0 µA

Reference Voltage Vref 3.0VVI-VO40V,10mAIO1.5A

PD20W

1.2 1.25 1.3 V

Temperature Stability Ts 0TJ125℃ - 0.7 - %VO

Minimum Load Current to

maintain Regulation

ILmin V

I-VO=40V - 3.5 10 mA

Maximum Output Current Imax VI-VO15V,PD20W

VI-VO40V,PD20W,TA=25℃

1. 5

0.15

2.2

0.4

-

A

RMS Noise N % of VO,TA=25℃,10Hzf10kHz - 0.003 - %VO

Ripple Rejection(Note 2) RR VO=10V,f=120Hz

Without CAdj

CAdj=10µF

-

66

65

80

-

dB

Long-Term Stability(Note 3) S TJ=125℃,TA=25℃ for endpoint

measurements

- 0.3 1.0 %/1.0k

Hrs

Notes:1.Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be

taken into account separately. Pulse testing with low duty cycle is used.

2.CAdj, when used, is connected between the adjustment pin and ground.

3.Since long-term stability cannot be measured on each device before shipment, this specification is an engineering

estimate of average stability from lot to lot.

4.Power dissipation within an IC voltage regulator produces a temperature gradient on the die, affecting individual IC

components on the die. These effects can be minimized by proper integrated circuit design and layout techniques.

Thermal regulation is the effect of these temperature gradients on the output voltage and is expressed in percentage

of output change per watt of power change in a specified time.

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 3/9

PL317E3 CYStek Product Specification

Representative Schematic Diagram

Vin

Vout

Adjust

+

Vcc

Cin 0.1μF

IAdj

Adjust

Vin Vout

PL317

R2

1%

R1

1%

Co 1μFRL

VIL

VIH VO

H

VOL

Fig 1. Line Regulation and IAdj/Line test circuit

Pulse testing required

1% Duty Cycle is

suggested

∣VOH-VOL∣

Line Regulation(%/V)= ×100

∣VOL∣

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 4/9

PL317E3 CYStek Product Specification

+

VI

Cin 0.1μF

IAdj

Adjust

Vin Vout

PL317

R2

1%

R1

1%

Co 1μFRL

IL

RL

(max load)

(min load)

*

Vo(min load

)

Vo(max load

)

*Pulse testing required.

1% Duty Cycle is sugges

t

+

Cin 0.1μF

IAdj

Adjust

Vin Vout

PL317

R2

1%

R1

1%

Co

1μFRL

IL

ISET

Vref

Vo

VI

Vo(min load)-Vo(max load)

Load Regulation(mV)=Vo(min load)-Vo(max load) Load Regulation(%Vo)= ×100

Vo(min load)

Fig 2. Load Regulation and IAdj/Load test circuit

＊ Pulse testing required.

1% Duty Cycle is suggested.

To calculate R2: Vout=ISETR2+1.250V

Assume ISET=5.25mA

Fig 3. Standard Test Circuit

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 5/9

PL317E3 CYStek Product Specification

+

Cin 0.1μF

Adjust

Vin Vout

PL317

R2

1%

R1

1%

Co

1μFRL

Vo

+

D1 *

CAdj 10μF

1N4002

Vout=10

V

* D1 Discharges CAdj if output is shorted to ground

24V

14V

f=120Hz

Application Information

Basic Circuit Operation

The PL317 is a 3-terminal floating regulator. In operation, the PL317 develops and maintains a nominal

1.25V reference (Vref) between its output and adjustment terminals. This reference voltage is converted

to a programming current (Iprog) by R1(see Fig 5), and this constant current flows through R2 to ground.

The regulated output voltage is given by:

Vout=Vref(1+R2/R1)+IAdjR2

Since the current from the adjustment terminal (IAdj) represents an error term in the equation, the PL317

was designed to control IAdj to less than 100 µA and keep it constant. To do this, all quiescent operating

current is returned to the output terminal. This imposes the requirement for a minimum load current. If

the load current is less than this minimum, the output voltage will rise.

Since the PL317 is a floating regulator, it is only the voltage differential across the circuit which is

important to performance, and operation at high voltages with respect to ground is possible.

R1

R2

Vout

Adjust

Vin Vout

IAdj

PL317

Iprog

Vref

Vref=1.25V typical

Fig 4. Ripple Rejection Test Circuit

Fig 5. Basic Circuit Configuration

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 6/9

PL317E3 CYStek Product Specification

Load Regulation

The PL317 is capable of providing extremely good load regulation, but a few precautions are needed to

obtain maximum performance. For best performance, the programming resistor (R1) should be connected

as close to the regulator as possible to minimize line drops which effectively appear in series with the

reference, thereby degrading regulation. The ground end of R2 can be returned near the load ground to

provide remote ground sensing and improve load regulation.

External Capacitors

A 0.1µF disc or 1.0µF tantalum input bypass capacitor (Cin) is recommended to reduce the sensitivity to

input line impedance.

The adjustment terminal may be bypassed to ground to improve ripple rejection. This capacitor (CAdj)

prevents ripple from being amplified as the output voltage is increased. A 10µF capacitor should improve

ripple rejection about 15 dB at 120 Hz in a 10V application.

Although the PL317 is stable with no output capacitance, like any feedback circuit, certain values of

external capacitance can cause excessive ringing. An output capacitance (Co) in the form of a 1.0µF

tantalum or 25µF aluminum electrolytic capacitor on the output swamps this effect and insures stability.

Protection Diodes

When external capacitors are used with any IC regulator, it is sometimes necessary to add protection

diodes to prevent the capacitors from discharging through low current points into the regulator.

Fig 6 shows the PL317 with the recommended protection diodes for output voltages in excess of 25V or

high capacitance values (Co>25µF,CAdj>10µF). Diode D1 prevents Co from discharging thru the IC

during an input short circuit. Diode D2 protects against capacitor CAdj discharging through the IC during

an output short circuit. The combination of diodes D1 and D2 prevents CAdj from discharging through the

IC during an input short circuit.

R1

R2

Vout

Adjust

Vin

PL317

+C

o

CAdj

D2

D1

1N4002

Cin 1N4002

Fig 6. Voltage Regulator with Protection Diodes

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 7/9

PL317E3 CYStek Product Specification

Application Circuits

+

-10V

Q2

2N5640

1N4001

D4

D3

Q1

2N3822

D2

D1

1N4001

1.0k 5.0k

RSC

D6*

1N4002

240 D5

10μF

1.0μF

Vout

Vout 2

Vin 2Vout

1N4001

Tantalum

Vin 1

Vin

32V to 40 V

0.1μF

Adjust 1

Current Limit Adjust

PL317 PL317

(1) (2)

Adjust 2

Iout

Voltage Adjust

Diodes D1 and D2 and transistor Q2 are added to

* D6 protects both LM317's during an input short circuit.

allow adjustment of output voltage to 0V.

Output Range:0≦Vo≦25V

0≦Io≦1.5A

Vss*

2N5640

D2

D1

1N400

1

1N400

1

100

R1

Vout

Vin

+25V

Adjust

PL317

Iout

1.25

R2

*To provide current limiting of Io to the system

groung, the source of the FET must be tied to a

negative voltage below -1.25V.

Fig 7. “Laboratory” Power Supply with Adjustable Current Limit and Output Voltage

R1=Vref/(Iomax+IDSS) R2Vref/IDSS

Vo <BVDSS+1.25V+Vss

ILmin-IDSS<Io<1.5A

As shown 0<Io<1.0A

Fig 8. Adjustable Current Limiter

+

PL317

Adjust

720 MPS2222

1.0k

TTL

Control

1.0μF

120

Vout

D1*

1N4002

Vin

*D1 protects the device during an input short circuit.

Fig 9. 5.0V Electronic Shutdown Regulator

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 8/9

PL317E3 CYStek Product Specification

PL317

Adjust

R2

MPS2907

240

Vout

Vin

+10μF

50k 1N4001

Fig 10. Slow Turn-on Regulator

R1

Vout

Adjust

Vin Iout

IAdj

PL317

Iout=(Vref/R1)+IAdj

=1.25V/R1

10mA≦Iout≦1.5A

Fig 11. Current Regulator

CYStech Electronics Corp.

Spec. No. : C513E3

Issued Date : 2003.04.09

Revised Date : . .

Page No. : 9/9

PL317E3 CYStek Product Specification

TO-220AB Dimension

*

: Typical

Inches Millimeters Inches Millimeters

DIM Min. Max. Min. Max.

A 0.2197 0.2949 5.58 7.49 I - *0.1508 - *3.83

B 0.3299 0.3504 8.38 8.90 K 0.0295 0.0374 0.75 0.95

C 0.1732 0.185 4.40 4.70 M 0.0449 0.0551 1.14 1.40

D 0.0453 0.0547 1.15 1.39 N - *0.1000 - *2.54

E 0.0138 0.0236 0.35 0.60 O 0.5000 0.5618 12.70 14.27

G 0.3803 0.4047 9.66 10.28 P 0.5701 0.6248 14.48 15.87

H -

*0.6398 - *16.25

Notes: 1.Controlling dimension: millimeters.

2.Maximum lead thickness includes lead finish thickness, and minimum lead thickness is the minimum thickness of base material.

3.If there is any question with packing specification or packing method, please contact your local CYStek sales office.

Material:

• Lead: 42 Alloy ; solder plating

• Mold Compound: Epoxy resin family, flammability solid burning class: UL94V-0

Important Notice:

• All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of CYStek.

• CYStek reserves the right to make changes to its products without notice.

• CYStek semiconductor products are not warranted to be suitable for use in Life-Support Applications, or systems.

• CYStek assumes no liability for any consequence of customer product design, infringement of patents, or application assistance.

AB

E

G

IK

M

O

P

3

2

1

C

N

H

D

4

Style: Pin 1.Adj 2.Vout 3.Vin

4.Vout

3-Lead TO-220AB Plastic Package

CYStek Package Code: E3

Marking:

317