LM117_LM217_LM317.pdf

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LM117/217

LM317

1.2V TO 37V VOLTAGE REGULATOR

OUTPUT VOLTAGE RANGE : 1.2 TO 37V

OUTPUT CURRENT IN EXCESS OF 1.5A

0.1% LINE AND LOAD REGULATION

FLOATING OPERATION FOR HIGH

VOLTAGES

COMPLETE SERIES OF PROTECTIONS :

CURRENT LIMITING, THERMAL

SHUTDOWN AND SOA CONTROL

DESCRIPTION

The LM117/LM217/LM317 are monolithic

integrated circuit in TO-220, TO-220FP, TO-3 and

D 2 PAK packages intended for use as positive

adjustable voltage regulators.

They are designed to supply more than 1.5A of

load current with an output voltage adjustable

over a 1.2 to 37V range.

The nominal output voltage is selected by means

of only a resistive divider, making the device

exceptionally easy to use and eliminating the

stocking of many fixed regulators.

TO-3

D 2 PAK

TO-220

TO-220FP

ABSOLUTE MAXIMUM RATING

Symbol

Parameter

Value

Unit

V i-o

Input-output Differential Voltage

I O

Output Current

I ntenrally Limited

T op

Operating Junction Temperature for: LM117

LM217

LM317

-55 to 150

-25 to 150

0 to 125

o o o C

P tot

Power Dissipation

I nternally Limited

T stg Storage Temperature

- 65 to 150

o C

THERMAL DATA

Symbol

Parameter

TO-3

TO-220

TO-220FP

D 2 PAK

Unit

R thj-ca se

R thj-amb

Thermal Resistance Junction-case

Max

62.5

o C/W

Thermal Resistance Junction-ambient

Max

November 2000

1/11

LM117/217/317

CONNECTION DIAGRAM AND ORDERING NUMBERS (top view)

TO-220

TO-220FP

D 2 PAK

TO-3

Type

TO-3

TO-220

TO-220FP

D 2 PAK

LM117

LM117K

LM217

LM217K

LM217T

LM217D2T

LM317

LM317K

LM317T

LM317P

LM317D2T

SCHEMATIC DIAGRAM

2/11

LM117/217/317

BASIC ADJUSTABLE REGULATOR

ELECTRICAL CHARACTERISTICS (V i -V o = 5 V, I o = 500 mA, I MAX = 1.5A and P MAX = 20W, unless

otherwise specified)

Symbol

Parameter

Test Conditions

LM117/LM217

LM317

Unit

Min. Typ. Max. Min. Typ. Max.

V o Line Regulation

V i -V o = 3 to 40 V

T j =25 o C

0.01 0.02

0.01 0.04 %/V

0.02 0.05

0.02 0.07 %/V

V o Load Regulation

I o =10mAtoI MAX

T j =25 o C

I o =10mAtoI MAX

T j =25 o C

0.1

0.3

0.1

0.5

0.3

1.5

I ADJ Adjustment Pin Current

100

I ADJ Adjustment Pin Current V i -V o = 2.5 to 40 V

I o =10mAtoI MAX

0.2

V REF Reference Voltage

(between pin 3 and pin

V i -V o = 2.5 to 40 V

I o =10mAtoI MAX

P D

.2.5. 3 .2.5.3 V

P MAX

Output Voltage

Temperature Stability

I o(min) Minimum Load Current V i -V o = 40 V

3.5

I o(max) Maximum Load

Current

15 V

P D <P MAX

.5.2

i -V o =40V

P D <P MAX

T j =25 o C

0.4

e N

Output Noise Voltage

(percentance of V O )

B = 10Hz to 10KHz

T j =25 o C

0.003

SVR Supply Voltage

Rejection (*)

T j =25 o C

f = 120 Hz

C ADJ =0

C ADJ =10

F 66

(*) CADJ is connected between pin 1 and ground.

Note:

(1) Unless otherwise specified the above specs, apply over the following conditions : LM 117 T j = – 55 to 150

LM 217 T j = – 25 to 150

C ; LM 317 T j = 0 to 125

3/11

V o

V i -V o 3

LM117/217/317

Figure 1 : Output Current vs. Input-output

Differential Voltage.

Figure 2 : Dropout Voltage vs. Junction

Temperature.

Figure 3 : Reference Voltage vs. Junction

Figure 4 : Basic Adjustable Regulator.

APPLICATION INFORMATION

The LM117/217/317 provides an internal

reference voltage of 1.25V between the output

and adjustments terminals. This is used to set a

constant current flow across an external resistor

divider (see fig. 4), giving an output voltage V O of:

voltage, supplies of very high voltage with respect

to ground can be regulated as long as the

maximum input-to-output differential is not

exceeded. Furthermore, programmable regulator

are easily obtainable and, by connecting a fixed

resistor between the adjustment and output, the

device can be used as a precision current

regulator.

In order to optimise the load regulation, the

current set resistor R1 (see fig. 4) should be tied

as close as possible to the regulator, while the

ground terminal of R2 should be near the ground

of the load to provide remote ground sensing.

Performance may be improved with added

capacitance as follow:

An input bypass capacitor of 0.1 m F

An adjustment terminal to ground 10 m F capacitor

V O =V REF

(

R 2

R 1 )

+I ADJ R 2

V R 2 can be neglected. To obtain the

previous requirement, all the regulator quiescent

current is returned to the output terminal,

imposing a minimum load current condition. If the

load is insufficient, the output voltage will rise.

Since the LM117/217317 is a floating regulator

and ”sees” only the input-to-output differential

4/11

The device was designed to minimize the term

I ADJ (100 m A max) and to maintain it very constant

with line and load changes. Usually, the error

term I ADJ

LM117/217/317

FAluminium electrolitic)

capacitor on the output to improve transient

response.

In additional to external capacitors, it is good

F tantalium (or 25

practice to add protection diodes, as shown in

fig.5.

D1 protect the device against input short circuit,

while D2 protect against output short circuit for

capacitance discharging.

Figure 5 : Voltage Regulator with Protection Diodes.

D1 protect the device against input short circuit, while D2 protects against output short circuit for capacitors discharging

Figure 6 : Slow Turn-on 15V Regulator.

Figure 7 : Current Regulator.

I o =

V ref

R 1 +

I ADJ 9

1.25V

R 1

5/11

to improve the ripple rejection of about 15 dB

(C ADJ ).

An 1

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