TL H 8446
LM368-25
Precision
Voltage
Reference
December 1994
LM368-2 5 Precision Voltage Reference
General Description
The LM368-2 5 is a precision monolithic temperature-com-
pensated voltage reference The LM368-2 5 makes use of
thin-film technology enhanced by the discrete laser trim-
ming of resistors to achieve excellent Temperature coeffi-
cient (Tempco) of V
OUT
(as low as 11 ppm C) along with
tight initial tolerance (as low as 0 02%) The trim scheme is
such that individual resistors are cut open rather than being
trimmed (partially cut) to avoid resistor drift caused by elec-
tromigration in the trimmed area The LM368-2 5 also pro-
vides excellent stability vs changes in input voltage and
output current The output is short circuit proof A trim pin is
made available for fine trimming of V
OUT
or for obtaining
intermediate values without greatly affecting the Tempco of
the device
Features
Y
400 mA operating current
Y
Low output impedance
Y
Excellent line regulation ( 0001% V typical)
Y
Single-supply operation
Y
Externally trimmable
Y
Low temperature coefficient
Y
Excellent initial accuracy (0 02% typical)
Y
Best reference available for low-voltage operation
(V
S
e
5V V
REF
e
2 500V)
Connection Diagram
Metal Can Package (TO-5)
TL H 8446 1
Top View
case connected to V
b
Order Number LM368H-2 5 LM368YH-2 5
See NS Package Number H08C
Typical Applications
Low Voltage Reference
TL H 8446 2
C1995 National Semiconductor Corporation
RRD-B30M115 Printed in U S A
Absolute Maximum Ratings
(Note 7)
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
Input Voltage
35V
Power Dissipation
600 mW
Storage Temperature Range
b
60 C to
a
150 C
Operating Temperature Range
0 C to
a
70 C
Soldering Information
TO-5 (H) Package (10 sec )
a
300 C
See AN-450 ``Surface Mounting Methods and Their Effect
on Product Reliability'' (Appendix D) for other methods of
soldering surface mount devices
Electrical Characteristics
(Note 1)
LM368-2 5
Tested
Design
Units
Parameter
Conditions
Typical
Limit
Limit
(Max unless
(Note 2)
(Note 3)
noted)
V
OUT
Error LM368
g
0 02
g
0 2
%
Line Regulation
5 0V
s
V
IN
s
30V
g
0 0001
g
0 0005
% V
Load Regulation (Note 8)
0 mA
s
I
SOURCE
s
10 mA
g
0 0003
g
0 0025
% mA
Thermal Regulation
T
e
20 mS (Note 4)
g
0 005
g
0 02
% 100 mW
Quiescent Current
350
550
m
A
Change of Quiescent Current vs V
IN
5 0V
s
V
IN
s
30V
3
5
m
A V
Temperature Coefficient
of V
OUT
(see graph) LM368Y-2 5
0 C
s
T
A
s
70 C
g
11
g
20
ppm C
(Note 5)
LM368-2 5
0 C
s
T
A
s
70 C
g
15
g
30
ppm C
Short Circuit Current
V
OUT
e
0
30
70
100
mA
Noise
0 1 10 Hz
12
uVp-p
100 Hz 10 kHz
420
nV
0
Hz
V
OUT
Adjust Range
0
s
V
PIN5
s
V
OUT
1 9 5 2
2 2 5 0
V min
Note 1
Unless otherwise noted these specifications apply T
A
e
25 C 4 9V
s
V
IN
s
10 5V 0
s
I
LOAD
s
0 5 mA 0
s
C
L
s
200 pF
Note 2
Tested Limits are guaranteed and 100% tested in production
Note 3
Design Limits are guaranteed (but not 100% production tested) over the indicated temperature and supply voltage ranges These limits are not used to
calculate outgoing quality levels
Note 4
Thermal Regulation is defined as the change in the output Voltage at a time T after a step change in power dissipation of 100 mW
Note 5
Temperature Coefficient of V
OUT
is defined as the worst case delta-V
OUT
measured at Specified Temperatures divided by the total span of the Specified
Temperature Range (See graphs) There is no guarantee that the Specified Temperatures are exactly at the minimum or maximum deviation
Note 6
In metal can (H) i
J-C
is 75 C W and i
J-A
is 150 C W
Note 7
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur DC and AC electrical specifications do not apply when operating
the device beyond its Rated Operating Conditions (see Note 1 and Conditions)
Note 8
Load regulation is measured on the output pin at a point
below the base of the package Regulation is measured at constant junction temperature
using pulse testing with a low duty cycle Changes in output voltage due to heating effects are covered under the specification for thermal regulation
2
Typical Performance Characteristics
(Note 1)
Quiescent Current vs Input
Voltage and Temperature
Dropout Voltage vs
Output Current
Output Change vs
Output Current
Output Impedance vs
Frequency
Ripple Rejection vs
Frequency
(1) LM368 as is
(2) with 0 01 mf Mylar Trim to Gnd
(3) with 10X in series with 10 mf
V
OUT
to Gnd
(4) with Both
Temperature Coefficient
LM368-2 5 (Curve A)
Output Noise vs
Frequency
TL H 8446 3
Typical Temperature Coefficient Calculations
LM368-2 5 (see Curve A)
T C
e
1 7 mV (70
c
2 5V)
e
9 7 ppm C
3
Typical Applications
Wide Range Trimmable Regulator
TL H 8446 5
Narrow Range Trimmable Regulator (
g
1% min )
TL H 8446 6
Improved Noise Performance
TL H 8446 7
g
2 5V
g
1 25V References
LM358A
e
LM324A or
TL H 8446 8
R
e
Thin Film Resistor Network
g
0 05% Matching and 5 ppm Tracking
(Beckman 694-3-R-10K-A)
(Caddock T-914-10K-100-05)
or similar
4
Typical Applications
(Continued)
Multiple Output Voltages
TL H 8446 10
R
e
Thin Film Resistor Network
0 05% Matching and 5 ppm Tracking
(Beckman 694-3-R-10K-A)
(Caddock T-914-10K-100-05)
or similar
TL H 8446 9
Reference with Booster
TL H 8446 11
100 mA Boosted Reference
TL H 8446 12
5
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