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璽erminal 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璷ut 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瑼rea Compensation
Floating Operation for High Voltage Applications
Eliminates Stocking many Fixed Voltages

Standard Application

PL317

Cout

Cin

Vin

Vout

Maximum Ratings

Rating Symbol

Value

Unit

Input-Output Voltage Differential

-V

Power Dissipation
T

=25

Thermal Resistance, Junction-to-Ambient
Thermal Resistance, Junction-to-Case

Internally Limited

5.0

Operating Junction Temperature Range

-40 to +125

Storage Temperature Range

Tstg

-65 to +150

TO-220AB

1.0礔

0.1礔

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.

out=

1.25(

)+I

Adj

Since

Adj

is controlled to less than 100 礎, the

error associated with this term is negligible in
most applications.

Adj

CYStech Electronics Corp.

Spec. No. : C513E3
Issued Date : 2003.04.09
Revised Date : . .
Page No. : 2/9

PL317E3

CYStek Product Specification

Electrical Characteristics

-V

=5V,I

=0.5A,T

=0 to 125, unless otherwise noted

)

Characteristics

Symbol

Conditions

Min Typ Max Unit

Line Regulation(

Note 1

)

Reg

line

=25,3.0VV

-V

40V

- 0.01

0.04 %/V

Load Regulation(

Note 1

) Reg

load

=25,10mAI

1.5A

5.0V

-
-

5.0
0.1

0.5

Thermal Regulation(

Note 4

)

Reg

therm

=25, 20ms pulse

- 0.03

0.07

Adjust Pin Current

Adj

- 50 100 礎

Adjust Pin Current Change I

Adj

2.5VV

-V

40V,10mAI

1.5A

20W

- 0.2 5.0 礎

Reference Voltage

Vref

3.0VV

-V

40V,10mAI

1.5A

20W

1.2 1.25 1.3 V

Temperature Stability

125

- 0.7 - %V

Minimum Load Current to
maintain Regulation

Lmin

-V

=40V -

3.5

Maximum Output Current Imax

-V

15V,P

20W

-V

40V,P

20W,T

=25

1. 5

0.15

2.2
0.4

-
-

RMS Noise

% of V

=25,10Hzf10kHz

- 0.003 - %V

Ripple Rejection(

Note 2

) RR V

=10V,f=120Hz

Without C

Adj

=10礔

65
80

-
-

Long-Term Stability(

Note 3)

=125,T

=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 V

due to heating effects must be

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

2.C

Adj

, 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

0.1F

IAdj

Adjust

Vin

Vout

PL317

VIL

VIH

VOH
VOL

Fig 1. Line Regulation and I

Adj

/Line test circuit

Pulse testing required
1% Duty Cycle is
suggested

-V

Line Regulation(%/V)= �100
V

CYStech Electronics Corp.

Spec. No. : C513E3
Issued Date : 2003.04.09
Revised Date : . .
Page No. : 4/9

PL317E3

CYStek Product Specification

Cin

0.1F

IAdj

Adjust

Vin

Vout

PL317

(max load)

(min load)

Vo(min load)
Vo(max load)

*Pulse testing required.

1% Duty Cycle is suggest

Cin

0.1F

IAdj

Adjust

Vin

Vout

PL317

ISET

Vref

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 I

Adj

/Load test circuit

Pulse testing required.

1% Duty Cycle is suggested.

To calculate R2: Vout=I

SET

R2+1.250V

Assume I

SET

=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

0.1F

Adjust

Vin

Vout

PL317

D1 *

CAdj

10F

1N4002

Vout=10V

* 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)+I

Adj

Since the current from the adjustment terminal (I

Adj

) represents an error term in the equation, the PL317

was designed to control I

Adj

to less than 100 礎 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.

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 0.1礔 disc or 1.0礔 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 (C

Adj

)

prevents ripple from being amplified as the output voltage is increased. A 10礔 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 1.0礔
tantalum or 25礔 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>25礔,C

Adj

>10礔). Diode D1 prevents Co from discharging thru the IC

during an input short circuit. Diode D2 protects against capacitor C

Adj

discharging through the IC during

an output short circuit. The combination of diodes D1 and D2 prevents C

Adj

from discharging through the

IC during an input short circuit.

Vout

Adjust

Vin

PL317

CAdj

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

2N5640

1N4001

2N3822

1N4001

1.0k

5.0k

RSC

D6*

1N4002

240

10F

1.0F

Vout

Vout 2

Vin 2

Vout

1N4001

Tantalum

Vin 1

Vin

32V to 40 V

0.1F

Adjust 1

Current Limit Adjust

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:0Vo25V

0Io1.5A

Vss*

2N5640

1N4001

100

Vout

Vin

+25V

Adjust

PL317

Iout

1.25

*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+I

DSS

) R2Vref/I

DSS

+1.25V+Vss

Lmin

-I

DSS

<Io<1.5A

As shown 0<Io<1.0A

Fig 8. Adjustable Current Limiter

PL317

Adjust

720

MPS2222

1.0k

TTL

Control

1.0F

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. : 9/9

PL317E3

CYStek Product Specification

TO-220AB Dimension

: Typical

Inches Millimeters

DIM

Min. Max. Min. Max.

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.

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

4.Vout

3-Lead TO-220AB Plastic Package

CYStek Package Code: E3

Marking:

317

协谢械泻褌褉芯薪薪褘泄 泻芯屑锌芯薪械薪褌: PL317E3

协谢械泻褌褉芯薪薪褘泄泻芯屑锌芯薪械薪褌: PL317E3