1-6
Silicon Diodes
1987
COMPE
Silicon Diodes
DT-470 and DT-471 Features and Description
DT-470 Features
•
Advanced, hermetic
ceramic and sapphire
packaging with the lowest
self-heating errors
•
Monotonic temperature
response over its useful
range from 1.4 K to 475 K
•
All sensors follow a
standard temperature
response curve (Curve 10)
•
Available in five tolerance
bands to a standard curve
(Curve 10)
•
Repeatability at 4.2 K
typically ±10 mK over
repeated thermal cycling
•
High sensitivity for critical
low temperature
measurements
•
Accommodates a variety
of mounting adapters and
probe assemblies
•
Useful above 60 K in
magnetic fields up to
5 tesla
•
SoftCal™ calibration
available
Interchangeable – The DT-470/471 Silicon
Diode temperature sensors incorporate
remarkably uniform sensing elements that
exhibit precise, repeatable, monotonic
temperature response over a wide range.
The elements are mounted into rugged,
hermetically-sealed packages that have been
specifically designed for proper thermal
behavior in a cryogenic environment. The result
is a family of sensors with temperature
characteristics so predictable, tightly grouped
and stable, that the sensors in most
applications can be routinely interchanged with
one another.
Repeatable – The small silicon chip in each
sensor has a temperature characteristic that is
well known and stable. The SD sensor package
is designed to withstand repeated cycling to low
temperatures without mechanical failure.
Repeatability at 4.2 K over repeated thermal
cycling from room temperature to helium
temperature is typically ±10 mK or better.
Repeatability from 1.4 K to 330 K is typically
better than ±20 mK. For long term stability, see
the specifications.
Accurate – All DT-470/471 Silicon Diodes follow
a standard temperature response curve, Curve
10 (See the Reference Section). For the DT-470
diodes, five tolerance bands are offered to allow
sensor selection that will meet both technical
and economic requirements. Within these five
bands, low temperature accuracies of ±0.25 K,
±0.5 K and ±1 K are available. For the DT-471
diodes, accuracy is ±1.5 K or ±1.5% of
temperature reading, whichever is greater, from
10 K to 475 K. For more demanding
requirements, DT-470/DT-471 diodes can be
used with SoftCal™, or these sensors can be
calibrated to accuracies of ±50 mK or better.
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Silicon Diodes
DT-470/DT-471-SD
Typical Magnetic Field-Dependent
Temperature Errors
(1)
∆T/T
(%)
at B (magnetic induction) for Silicon Diodes
Package Base Parallel to Field
B (tesla)
1
2
3
4
-200
-300
-10
-20
-4
-6
-0.5
-1
< 0.1
-0.5
< -0.1 < -0.1
-350
-25
-8
-2
-0.8
< -0.1
-400
-30
-10
-3
-1.1
< -0.1
T(K)
4.2
20
40
60
80
300
5
-500
-40
-12
-3.5
-1.5
< -0.1
T(K)
4.2
20
40
60
80
300
Package Base Perpendicular to Field
B (tesla)
1
2
3
4
5
-8
-4
-1.5
-0.5
-0.1
<0.1
-9
-5
-3
-0.7
-0.3
0.2
-11
-5
-4
-0.8
-0.5
0.5
-15
-5
-5
-1
-0.6
0.6
-20
-10
-5.5
-1.1
-0.7
0.6
DT-471 Features
•
Temperature range: 10 K
to 475 K
•
Follows Curve 10 from
10 K to 475 K
•
Accuracy: ±1.5 K or
±1.5% of temperature
reading, whichever is
greater
•
Shares other benefits with
the DT-470
Repeatability
Sensitivity
Mounting
B dependence
•
SoftCal™ calibration
available
(1) As can be seen from the table above, magnetic
field-induced temperature errors are strongly
orientation dependent. To minimize this effect, the
sensor should be oriented so that the package base is
perpendicular to the magnetic field flux lines; this
results in the diode current being parallel to the
magnetic field.
The DT-471 Silicon Diode sensors offer an
inexpensive alternative for situations in
which temperature measurement below
10 K is not necessary and a tolerance band
wider than Band 13 is acceptable. The upper
operating temperature is 475 K for the Model
DT-471-SD, and it's available with (CO)
mounting adapter to 475 K. Because the
DT-471 package/mounting adapter
configurations are identical to those for the
DT-470 diodes, installation and operation
procedures are identical.
What is SoftCal™ ?
SoftCal™ is a 2-point or 3-point calibration
which offers improved accuracy without the cost
of a full calibration. SoftCal™ is available for
Silicon Diodes and platinum sensors.
For detailed information on SoftCal™,
CalCurve™ and Curve 10, see the Reference
Section.
Lake Shore
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(614) 891-2244
Fax:
(614) 818-1600
www.lakeshore.com EMail:
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Silicon Diodes
1-7
DT-414, DT-420 Series Features and Description
DT-414 Features
•
Temperature range:
1.4 K to 375 K
(Calibration not
available above 325 K)
•
Small mass for rapid
thermal response
•
Incorporates
non-magnetic materials
DT-414 Unencapsulated Silicon Diodes
The Model DT-414 uses the Silicon Diode chip
used in the DT-470s. It is mounted on a flat
substrate. This chip-level sensor offers
minimal thermal mass and minimal physical
size. Die attachment is with silver epoxy. The
chip is unencapsulated, leaving the fragile
gold wires exposed.
The DT-414 is supplied in a Gel-Pak™ with
0.5" to 1" long, 50
µm
diameter gold leads. If it
is desired to wirebond the chip into a circuit
using the user's wire, the gold ball bonds can
be removed using a sharp blade. This will
leave more room for attachment of new gold
or aluminum wire. The leads (as supplied) can
also be thermo-compression bonded or
soldered at their free ends.
Silicon Diodes
DT-420 Features
•
Temperature range:
1.4 K to 325 K
•
Repeatability (at 4.2 K)
typically ±50 mK over
repeated thermal
cycling
•
Exposed flat substrate
for surface mounting
•
Incorporates
non-magnetic materials
•
Small mass for rapid
thermal response
DT-420 Miniature Silicon Diode
The DT-420 subminiature Silicon Diode
temperature sensor is configured for
installation on flat surfaces. The DT-420
sensor package exhibits precise, monotonic
temperature response over its useful range
and is designed to withstand repeated cycling
to low temperatures without mechanical
failure. The sensor chip is in direct contact
with the epoxy dome which causes increased
voltage at 4.2 K and prevents full range
conformity to the Curve 10. The anode lead is
electrically connected to the platinum base
and should be isolated by the user for
installation on metallic surfaces (see
Reference Section). Also see the Accuracy
specification for the difference between the
DT-421 and DT-422.
Typical Voltage and Sensitivity Values for Silicon Diodes
Lake Shore
¤
(614) 891-2244
Fax:
(614) 818-1600
www.lakeshore.com EMail:
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1-8
Silicon Diodes
Specifications
Temperature
Useful range
Minimum
Maximum
Maximum storage temperature
Standard curve
Voltage (typical)
Sensitivity (typical)
Repeatability (typically)
Accuracy (interchangeability)
Accuracy (SoftCal™)
2 point
(77 K and 305 K)
DT-470-SD and DT-471-SD
DT-414
Silicon Diodes
1.4 K (10 K for the DT-471)
1.4 K
475 K
375 K
305 K
305 K
Curve 10 (5 tolerance bands for DT-470)
Curve 10
1.626 V at 4.2 K; 1.020 V at 77 K; 0.507 V at 305 K (both models)
-33.6 mV/K at 4.2 K (DT-470 only); -1.91 mV/K at 77 K;
-33.6 mV/K at 4.2 K; -1.91 mV/K at 77 K;
-2.41 mV/K at 305 K
-2.41 mV/K at 305 K
±10 mK or better at 4.2 K; ±20 mK (1.4 K to 330 K)
±10 mK or better at 4.2 K; ±20 mK (1.4 K to 330 K)
DT-470: Curve 10 (Band 11 to Band 13
±1.5 K or ±1.5% whichever is greater
DT-471: ±1.5 K or ±1.5% whichever is greater(10 K to 475 K)
±0.25 K (30 K to 60 K)
±0.15 K (60 K to 345 K)
±0.25 K (345 K to 375 K)
±1.0 K (375 K to 475 K)
±0.5 K (2 K to 30 K)
±0.25 K (30 K to 60 K)
±0.15 K (60 K to 345 K)
± 0.25 K (345 K to 375 K)
±1.0 K (375 K to 475 K)
Not applicable
3 point (DT-470 only)
(4.2 K, 77 K and 305 K)
Not applicable
Accuracy (calibrated)
Stability
Short-term
Long-term (per year)
Thermal response time (SD package)
Recommended recalibration schedule
Excitation
Recommended
Maximum reverse voltage (diode)
Maximum forward current (diode)
Maximum current before damage
Dissipation at rated excitation
Units range
Lead wire configuration (polarity)
Physical Specifications
Materials in the sensor/construction
±20 mK < 10 K; ±50 mK (10 K to 330 K); ±55 mK (330 K to 475 K) (all models)
±20 mK or better (1.4 K to 330 K)
±10 mK or better at 4.2 K
±20 mK or better (1.4 K to 330 K)
±10 mK/year at 4.2 K
±10 mK/year at 4.2 K
±40 mK/year at 77 K
±40 mK/year at 77 K
±25 mK/year at 300 K
±25 mK/year at 300 K
Typical <10 milliseconds at 4.2 K; 100 milliseconds at 77 K; 200 milliseconds at 305 K (all models)
Annual
Annual
10
µA
±0.05%
10
µA
±0.05%
40 VDC
40 VDC
500
µA
continuous or 5 mA in <100 microsecond pulses (all models)
1 mA continuous
1 mA continuous
17
µW
at 4.2 K; 10
µW
at 77 K; 5
µW
at 300 K
17
µW
at 4.2 K; 10
µW
at 77 K; 5
µW
at 300 K
0 to 2 volts
0 to 2 volts
Positive lead on right with package lid up
Positive lead on left with chip up and
and leads towards user.
leads towards user.
Sapphire base with alumina body and lid
Molybdenum/manganese metallization on base and lid
top with nickel and gold plating. Gold-tin solder as
hermetic lid seal. Silicon chip with aluminum metallization.
1 mm high x 1.9 mm wide x 3.2 mm long
37 milligrams
0.38 mm x 0.1 mm thick x 12.7 mm long
Two (2)
Nickel and gold plated Kovar
None
Package hermetically sealed
Alumina base, with metallization 0.1 mm of
molybdenum, 0.2 mm gold
0.5 mm high x 0.63 mm wide x 1.52 mm dia.
3 milligrams
50
µm
diameter x 2.54 mm long
Two (2)
Gold
None
Not applicable
Size
Mass
Leads
Size
Number
Material
Insulation
Internal atmosphere
Environmental
Radiation effects
Magnetic fields
Vacuum vs. liquid differences at 4.2 K
ESD sensitivity
Noise sensitivity
See Reference Section
See Reference Section
Not recommended for use in magnetic field applications below 60 K. Low magnetic field dependence when
used in fields up to 5 tesla above 60 K (all three models).
Typically 5 mK to 35 mK depending on configuration. See application note Self-heating Temperature
Errors in Silicon Diode Temperature Sensors in the Reference Section (both models).
Better than 3000 static volts
3000 static volts
Can be significant
(1)
Can be significant
(1)
(1) See the application note titled "Measurement system induced errors in diode thermometry,"
Rev. Sci. Instrum. 57 (4),
April 1986. Lake Shore order number 1420.
Also see the Reference Section.
Lake Shore
¤
(614) 891-2244
Fax:
(614) 818-1600
www.lakeshore.com EMail:
sales@lakeshore.com
Silicon Diodes
1-9
Specifications
Temperature
Useful range
Minimum
Maximum
Maximum storage temperature
Standard curve
DT-421/ 422
1.4 K (must be calibrated for use below 10 K)
325 K
305 K
DT-421 follows Curve 10 to a tolerance of 2.0 K or 1.5%
of temperature from 10 K to 325 K, whichever is greater.
DT-422 follows Curve 10 to a tolerance of 1.0 K or 1.0%
of temperature from 40 K to 325 K, whichever is greater.
1.789 V at 4.2 K; 1.020 V at 77 K; 0.507 V at 305 K
-36 mV/K at 4.2 K; -2 mV/K at 100 K; -2.4 mV/K at 305 K
Repeatability at 4.2 K is required to be better than ±50 mK over three thermal cycles for device acceptance.
Repeatability is typically better than ±10 mK.
DT-421: ±2 K or ±1.5% temperature from 10 K to 325 K, whichever is greater
DT-422: ±2 K from 10 K to 40 K; Band 13; from 40 K to 325 K, whichever is greater
2 point:
±0.25 K (30 K to 60 K)
±0.15 K (60 K to 325 K)
±50 mK or better
±25 mK at 4.2 K
±10 mK/year at 4.2 K
±40 mK/year at 77 K
±25 mK/year at 300 K
<10 milliseconds at 4.2 K; 100 milliseconds at 77 K; 200 milliseconds at 305 K (both models)
Annual
10
µA
±0.05%
40 VDC
500
µA
continuous or 5 mA in <100 microsecond pulses
2 mW continuous
17
µW
at 4.2 K; 10
µW
at 77 K, 5
µW
at 300 K
0 to 2 volts
Positive lead is right-hand ribbon with the platinum disk down and the leads towards the user.
The sensing element is mounted to a platinum disk and covered with a dome of Stycast
®
epoxy.
<1 mm high x 1.25 mm diameter
23 milligrams
0.5 mm x 0.25 mm x 25 mm long
Two (2)
Platinum ribbon with ends tinned with 60/40 PbSn solder.
None
See Reference Section
Not recommended for use in magnetic field applications below 60 K. Low magnetic field dependence when used
in fields up to 5 tesla above 60 K.
<100 mK at 4.2 K typical greased to copper block in vacuum
3000 static volts or better
Can be significant
(1)
Silicon Diodes
Voltage (typical)
Sensitivity (typical)
Repeatability
Accuracy (interchangeability)
Accuracy (SoftCal™)
Accuracy (calibrated)
Stability
Short-term
Long-term (per year)
Thermal response time
Recommended recalibration schedule
Excitation
Recommended
Maximum reverse voltage (diode)
Maximum forward current (diode)
Maximum power before damage
Dissipation at rated excitation
Units range
Lead wire configuration (polarity)
Physical Specifications
Materials in the sensor/construction
Size in millimeters
Mass
Leads
Size
Number
Material
Insulation
Environmental
Radiation effects
Magnetic fields
Vacuum vs. liquid differences
ESD sensitivity
Noise sensitivity
(1) See the application note titled "Measurement system induced errors in diode thermometry,"
Rev. Sci. Instrum. 57 (4),
April 1986. Lake Shore order number 1420.
Also see the Reference Section.
For information on Packages
for Sensor Installation,
see pages 1-40 to 1-42.
Adding lead length to
sensors - see page 1-43.
Lake Shore
¤
(614) 891-2244
Fax:
(614) 818-1600
www.lakeshore.com EMail:
sales@lakeshore.com
1-10
Silicon Diodes
Curve 10
Measurement Current = 10 microamperes, ±0.05%
All DT-470, DT-471, DT-421*,
DT-422* and DT-414 Silicon
Diode temperature sensors
follow the same standard
temperature response curve,
Curve 10 (table below).
Consequently, Lake Shore's
Silicon Diodes can be
interchanged with one another
routinely in any application
utilizing this response curve.
Curve 10 is programmed into
all Lake Shore temperature
controllers, digital
thermometers and cryopump
monitors.
Shaded portion highlights truncated portion of Curve 10 corresponding to the
reduced temperature range of DT-471 diode sensors. Note that packaging may
limit the allowable temperature range, especially at the high end.
* Partial conformances
T
(K)
1.40
1.60
1.80
2.00
2.20
2.40
2.60
2.80
3.00
3.20
3.40
3.60
3.80
4.00
4.20
4.40
4.60
4.80
5.00
5.50
6.00
6.50
7.00
7.50
8.00
8.50
9.00
9.50
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
Tolerance Bands for
DT-470 Silicon Diodes
Standard Curve 10 Tolerance Bands
Band
11
11A
12
12A
13
2 K - 100 K
± 0.25 K
± 0.25 K
± 0.5 K
± 0.5 K
± 1.0 K
100 K - 305 K
± 0.5 K
± 1% of temp.
± 1.0 K
± 1% of temp.
305 K - 475 K
± 1.0 K
± 1% of temp.
± 2.0 K
± 1% of temp.
Silicon Diodes
± 1% of temperature
Voltage
(V)
1.69812
1.69521
1.69177
1.68786
1.68352
1.67880
1.67376
1.66845
1.66292
1.65721
1.65134
1.64529
1.63905
1.63263
1.62602
1.61920
1.61220
1.60506
1.59782
1.57928
1.56027
1.54097
1.52166
1.50272
1.48443
1.46700
1.45048
1.43488
1.42013
1.40615
1.39287
1.38021
1.36809
1.35647
1.34530
1.33453
1.32412
1.31403
1.30422
1.29464
1.28527
dV/dT
(mV/K)
-13.1
-15.9
-18.4
-20.7
-22.7
-24.4
-25.9
-27.1
-28.1
-29.0
-29.8
-30.7
-31.6
-32.7
-33.6
-34.6
-35.4
-36.0
-36.5
-37.6
-38.4
-38.7
-38.4
-37.3
-35.8
-34.0
-32.1
-30.3
-28.7
-27.2
-25.9
-24.8
-23.7
-22.8
-21.9
-21.2
-20.5
-19.9
-19.4
-18.9
-18.6
T
(K)
16.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
21.0
22.0
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
32.0
34.0
36.0
38.0
40.0
42.0
44.0
46.0
48.0
50.0
52.0
54.0
56.0
58.0
60.0
65.0
70.0
75.0
77.35
80.0
85.0
90.0
95.0
Voltage
(V)
1.27607
1.26702
1.25810
1.24928
1.24053
1.23184
1.22314
1.21440
1.19645
1.17705
1.15558
1.13598
1.12463
1.11896
1.11517
1.11212
1.10945
1.10702
1.10263
1.09864
1.09490
1.09131
1.08781
1.08436
1.08093
1.07748
1.07402
1.07053
1.06700
1.06346
1.05988
1.05629
1.05267
1.04353
1.03425
1.02482
1.02032
1.01525
1.00552
0.99565
0.98564
dV/dT
(mV/K)
-18.2
-18.0
-17.7
-17.6
-17.4
-17.4
-17.4
-17.6
-18.5
-20.6
-21.7
-15.9
-7.72
-4.34
-3.34
-2.82
-2.53
-2.34
-2.08
-1.92
-1.83
-1.77
-1.74
-1.72
-1.72
-1.73
-1.74
-1.75
-1.77
-1.78
-1.79
-1.80
-1.81
-1.84
-1.87
-1.91
-1.92
-1.93
-1.96
-1.99
-2.02
T
(K)
100.0
110.0
120.0
130.0
140.0
150.0
160.0
170.0
180.0
190.0
200.0
210.0
220.0
230.0
240.0
250.0
260.0
270.0
273.15
280.0
290.0
300.0
305.0
310.0
320.0
330.0
340.0
350.0
360.0
370.0
380.0
390.0
400.0
410.0
420.0
430.0
440.0
450.0
460.0
470.0
475.0
Voltage
(V)
0.97550
0.95487
0.93383
0.91243
0.89072
0.86873
0.84650
0.82404
0.80138
0.77855
0.75554
0.73238
0.70908
0.68564
0.66208
0.63841
0.61465
0.59080
0.58327
0.56690
0.54294
0.51892
0.50688
0.49484
0.47069
0.44647
0.42221
0.39783
0.37337
0.34881
0.32416
0.29941
0.27456
0.24963
0.22463
0.19961
0.17464
0.14985
0.12547
0.10191
0.09062
dV/dT
(mV/K)
-2.04
-2.08
-2.12
-2.16
-2.19
-2.21
-2.24
-2.26
-2.28
-2.29
-2.31
-2.32
-2.34
-2.35
-2.36
-2.37
-2.38
-2.39
-2.39
-2.39
-2.40
-2.40
-2.41
-2.41
-2.42
-2.42
-2.43
-2.44
-2.45
-2.46
-2.47
-2.48
-2.49
-2.50
-2.50
-2.50
-2.49
-2.46
-2.41
-2.30
-2.22
Lake Shore
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