LM117/217
LM317
1.2V TO 37V VOLTAGE REGULATOR
November 1999
s
OUTPUT VOLTAGE RANGE : 1.2 TO 37V
s
OUTPUT CURRENT IN EXCESS OF 1.5A
s
0.1% LINE AND LOAD REGULATION
s
FLOATING OPERATION FOR HIGH
VOLTAGES
s
COMPLETE SERIES OF PROTECTIONS :
CURRENT LIMITING, THERMAL
SHUTDOWN AND SOA CONTROL
DESCRIPTION
The
LM117/LM217/LM317
are
monolithic
integrated circuit in TO-220, ISOWATT220, 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
TO-220
D
2
PAK
ABSOLUTE MAXIMUM RATING
Symbol
Parameter
Value
Unit
V
i-o
Input-output Differential Voltage
40
V
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
C
o
C
o
C
P
tot
Power Dissipation
I nternally Limited
T
st g
Storage Temperature
- 65 to 150
o
C
THERMAL DATA
Symbol
Parameter
TO-3
TO-220
ISOW ATT220
D
2
PAK
Unit
R
thj- ca se
R
thj- amb
Thermal Resistance Junction-case
Max
Thermal Resistance Junction-ambient
Max
4
35
3
50
4
60
3
62. 5
o
C/W
o
C/W
ISOWATT220
1/11
CONNECTION DIAGRAM AND ORDERING NUMBERS (top view)
TO-220
D
2
PAK
TO-3
Type
TO-3
TO-220
ISOWATT220
D
2
PAK
LM117
LM117K
LM217
LM217K
LM217T
LM217D2T
LM317
LM317K
LM317T
LM317P
LM317D2T
SCHEMATIC DIAGRAM
ISOWATT220
LM117/217/317
2/11
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
V
o
5V
I
o
= 10 mA to I
MAX
T
j
= 25
o
C
5
15
5
25
mV
20
50
20
70
mV
V
o
5V
I
o
= 10 mA to I
MAX
T
j
= 25
o
C
0.1
0. 3
0.1
0.5
%
0.3
1
0.3
1.5
%
I
ADJ
Adjustment Pin Current
50
100
50
100
A
I
ADJ
Adjustment Pin Current V
i
- V
o
= 2.5 to 40 V
I
o
= 10 mA to I
MAX
0.2
5
0.2
5
A
V
REF
Reference Voltage
(between pin 3 and pin
1)
V
i
- V
o
= 2.5 to 40 V
I
o
= 10 mA to I
MAX
P
D
P
MAX
1.2
1.25
1. 3
1.2
1.25
1.3
V
V
o
V
o
Output Voltage
Temperature Stability
1
1
%
I
o (m in)
Minimum Load Current V
i
- V
o
= 40 V
3.5
5
3.5
10
mA
I
o (max )
Maximum Load
Current
V
i
- V
o
15 V
P
D
< P
MAX
1.5
2.2
1.5
2.2
A
V
i
- V
o
= 40 V
P
D
< P
MAX
T
j
= 25
o
C
0.4
0.4
A
e
N
Output Noise Voltage
(percentance of V
O
)
B = 10Hz to 10KHz
T
j
= 25
o
C
0.003
0.003
%
SVR
Supply Voltage
Rejection (*)
T
j
= 25
o
C
f = 120 Hz
C
ADJ
=0
65
65
dB
C
ADJ
=10
F
66
80
66
80
dB
(*) 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
C;
LM 217 T
j
= 25 to 150
C ; LM 317 T
j
= 0 to 125
C.
LM117/217/317
3/11
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:
V
O
= V
REF
(
1
+
R
2
R
1
)
+ I
ADJ
R
2
The device was designed to minimize the term
I
ADJ
(100
A max) and to maintain it very constant
with line and load changes. Usually, the error
term I
ADJ
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
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
F
An adjustment terminal to ground 10
F capacitor
Figure 4 : Basic Adjustable Regulator.
Figure 1 : Output Current vs. Input-output
Differential Voltage.
Figure 2 : Dropout Voltage vs. Junction
Temperature.
Figure 3 : Reference Voltage vs. Junction
LM117/217/317
4/11
to improve the ripple rejection of about 15 dB
(C
ADJ
).
An 1
F tantalium (or 25
FAluminium electrolitic)
capacitor on the output to improve transient
response.
In additional to external capacitors, it is good
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
r ef
R
1
+
I
ADJ
1.25
V
R
1
LM117/217/317
5/11
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