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PDF LM369H Data sheet ( Hoja de datos )
| Número de pieza | LM369H | |
| Descripción | Precision Voltage Reference | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de LM369H (archivo pdf) en la parte inferior de esta página. Total 14 Páginas | ||
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December 1994
LM169 LM369 Precision Voltage Reference
General Description
The LM169 LM369 are precision monolithic temperature-
compensated voltage references They are based on a bur-
ied zener reference as pioneered in the LM199 references
but do not require any heater as they rely on special tem-
perature-compensation techniques (Patent Pending) The
LM169 makes use of thin-film technology enhanced by the
discrete laser trimming of resistors to achieve excellent
Temperature coefficient (Tempco) of Vout (as low as 1
ppm C) along with tight initial tolerances (as low as 0 05%
max) The trim scheme is such that individual resistors are
cut open rather than being trimmed (partially cut) to avoid
resistor drift caused by electromigration in the trimmed area
The LM169 also provides excellent stability vs changes in
input voltage and output current (both sourcing and sinking)
The devices have a 10 000V output and will operate in ei-
ther series or shunt mode the output is short-circuit-proof to
ground A trim pin is available which permits fine-trimming of
Vout and also permits filtering to greatly decrease the out-
put noise by adding a small capacitor (0 05 to 0 5 mF)
Features
Y Low Tempco
3 ppm C (max)
Y Excellent initial accuracy
g5 mV (max)
Y Excellent line regulation
4 ppm V (max)
Y Excellent output impedance
g0 8X (max)
Y Excellent thermal regulation g20 ppm 100 mW (max)
Y Low noise
Y Easy to filter output noise
Y Operates in series or shunt mode
Applications
Y High-Resolution Data Acquisition Systems
Y Digital volt meters
Y Weighing systems
Y Precision current sources
Y Test Equipment
Connection Diagrams
Metal Can Package (H)
Dual-In-Line Package (N)
or S O Package (M)
Top View
TL H 9110 – 5
Top View
(Case is connected to ground )
TL H 9110 – 1
Do not connect internal connection for factory trims
Order Number LM169H LM169BH
LM169H 883 LM369H or LM369BH
See NS Package Number H08C
Order Number LM369DM LM369DMX LM369N
LM369BN LM369CN or LM369DN
See NS Package Number M08A or N08E
X denotes 2500 units on Tape and Reel and is not included in the device
part number marking
TO-226 Plastic Package (RC)
Bottom View
TL H 9110 – 28
Order Number LM369DRC
See NS Package Number RC03A
Teflon and Mylar are registered trademarks of E I DuPont Corp
C1995 National Semiconductor Corporation TL H 9110
RRD-B30M115 Printed in U S A
1 page  
Application Hints
The LM169 LM369 can be applied in the same way as any
other voltage reference The adjacent Typical Applications
Circuits suggest various uses for the LM169 LM369 The
LM169 is recommended for applications where the highest
stability and lowest noise is required over the full military
temperature range The LM369 is suitable for limited-tem-
perature operation The curves showing the Noise vs Ca-
pacitance in the Typical Performance Characteristics sec-
tion show graphically that a modest capacitance of 0 1 to
0 3 microfarads can cut the broadband noise down to a lev-
el of only a few microvolts less than 1 ppm of the output
voltage The capacitor used should be a low-leakage type
For the temperature range 0 to 50 C polyester or Mylar
will be suitable but at higher temperatures a premium film
capacitor such as polypropylene is recommended For oper-
ation at a125 C a Teflon capacitor would be required to
ensure sufficiently low leakage Ceramic capacitors may
seem to do the job but are not recommended for produc-
tion use as the high-K ceramics cannot be guaranteed for
low leakage and may exhibit piezo-electric effects convert-
ing vibration or mechanical stress into excessive electrical
noise
Additionally the inherent superiority of the LM169 369’s
buried Zener diode provides freedom from low-frequency
noise wobble and jitter in the frequency range 0 01 to 10
Hertz where capacitive filtering is not feasible
Pins 1 3 7 and 8 of the LM169 369 are connected to
internal trim circuits which are used to trim the device’s out-
put voltage and Tempco during final testing at the factory
Do not connect anything to these pins or improper opera-
tion may result These pins would not be damaged by a
short to ground or by Electrostatic Discharges however
keep them away from large transients or AC signals as
stray capacitance could couple noises into the output
These pins may be cut off if desired Alternatively a shield
foil can be laid out on the printed circuit board surrounding
these pins and pin 5 and this guard foil can be connected to
ground or to Vout effectively acting as a guard against AC
coupling and DC leakages
The trim pin (pin 5) should also be guarded away from noise
signals and leakages as it has a sensitivity of 15 millivolts of
DVout per microampere The trim pin can also be used in
the circuits shown to provide an output trim range of g10
millivolts Trimming to a wider range is possible but is not
recommended as it may degrade the Tempco and the
Tempco linearity at temperature extremes For example if
the output were trimmed up to 10 240V the Tempco would
be degraded by 8 ppm C As a general rule Tempco will
be degraded by 1 ppm C per 30 mV of output adjustment
The output can sink current as well as source it but the
output impedance is much better for sourcing current Also
the LM169 369 requires a 0 1 mF tantalum capacitor (or
0 1 mF in series with 10X) bypass from the output to ground
for stable operation in shunt mode (output sinking current)
The output has a class-B stage so if the load current chang-
es from sourcing to sinking an output transient will occur
To avoid this transient it may be advisable to preload the
output with a few milliamperes of load to ground The
LM169 369 does have an excellent tolerance of load ca-
pacitance and in cases of load transients electrolytic or
tantalum capacitors in the range 1 to 500 microfarads have
been shown to improve the output impedance without de-
grading the dynamic stability of the device The LM169 369
are rated to drive an output of g10 mA but for best accura-
cy any load current larger than 1 mA can cause thermal
errors (such as 1 mA c 5V c 4 ppm 100 mW e 0 2 ppm
or 2 microvolts) and degrade the ultimate precision of the
output voltage
The output is short-circuit-proof to ground However avoid
overloads at high ambient temperatures as a prolonged
short-circuit may cause the junction temperature to exceed
the Absolute Maximum Temperature The device does not
include a thermal shut-down circuit If the output is pulled to
a positive voltage such as a15 or a20V the output current
will be limited but overheating may occur Avoid such over-
loads for voltages higher than a20 V for more than 5 sec-
onds or at high ambient temperatures
The LM169 369 has an excellent long-term stability and is
suitable for use in high-resolution Digital Voltmeters or Data
Acquisition systems Its long-term stability is typically 3 to 10
ppm per 1000 hours when held near Tmax and slightly bet-
ter when operated at room temperature Contact the factory
for availability of devices with proven long-term stability
Typical Applications
Series Reference
Shunt Reference with Optional Trim
Series Reference with
Optional Filter
for Reduced Noise
TL H 9110–2
NOTE Pin numbers for H M or N packages
TL H 9110 – 3
5
TL H 9110 – 4
5 Page 
Physical Dimensions inches (millimeters)
Metal Can Package (H)
Order Number LM169BH LM169H
LM169H 883 LM369BH or LM369H
NS Package Number H08C
11
11 Page | ||
| Páginas | Total 14 Páginas | |
| PDF Descargar | [ Datasheet LM369H.PDF ] | |
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