1
LTK001
001fa
, LTC and LT are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. For typical performance curves and
applications circuits consult the LT1025 data sheet.
■
0.75°C Initial Accuracy (A Version)
■
Extremely Low Warmup Drift
■
Preset Outputs for Type E, J, K, R, S, T
■
Single 5V to ± 20V Operation
■
480µA Typical Supply Current
■
Available in 8-Pin DIP Package
■
Thermocouple Cold Junction Compensation
Thermocouple Cold Junction
Compensator and
Matched Amplifier
Type K 10mV/°C Thermometer
The LTK001 is a thermocouple amplifier supplied with a
matched cold junction compensator. By separating the
amplifier and compensator functions, the problem of
compensator temperature rise is virtually eliminated. The
compensator is a selected version of the LT
®
1025 cold
junction compensator. The amplifier, which is also avail-
able separately as LTKA0x has been specially selected for
thermocouple applications. It has low supply current to
minimize warmup drift, very low offset voltage (<35µV),
high gain, and extremely low input bias currents (<600pA)
to allow high impedance input filters to be used without
degrading offset voltage or drift.
Matching of the kits is accomplished by separating the
compensators and amplifiers according to the polarity of
their initial (room temperature) errors. This eliminates the
need to sum the errors of the two components to find the
worst-case error.
The LTK001 has direct thermocouple outputs of
60.9µV/°C (E), 51.7µV/°C (J), 40.6µV/°C (K, T), and
5.95µV/°C
(R, S). It also has a 10mV/°C output which can
be scaled to match any arbitrary thermocouple.
For multiple thermocouple applications using one com-
pensator, amplifiers may be ordered separately (LTKA0x),
still matched to the compensator.
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
–
+
V+
V–
V+
V–
LTKA0x
R4*
TYPE K
GND R–
K
V0
VOUT
10mV/°C
VIN
LT1025 C1
0.1µF
C2
0.1µF
R1
1k
1%
R3**
255k
1%
R2
100Ω
FULL-SCALE TRIM
+– *
V–
*R4 ≤ 30µA , R4 IS NOT REQUIRED (OPEN) FOR
LT1025 TEMPERATURES ≥ 0°C.
**SELECTED FOR 0°C–100°C RANGE LTK001 TA01
TYPICAL APPLICATIO
U
2
LTK001
001fa
Amplifier (LTKA0x)
Supply Voltage (Total V
+
to V
–
) ............................... 40V
Differential Input Current (Note 2) ...................... ±10mA
Common Mode Input Voltage ............. Equal to Supplies
Output Short-Circuit Duration .......................... Indefinite
Compensator (LT1025)
Supply Voltage (V
IN
to Ground Pin) ......................... 36V
Output Voltage (Forced) ............................................ 5V
Output Short-Circuit Duration .......................... Indefinite
PACKAGE/ORDER I FOR ATIO
UU
W
ABSOLUTE AXI U RATI GS
WWWU
Note A: The polarity of the amplifier is indicated by the 0 or 1 in the part
number. An LT1025 with a 0 identifier is properly matched with an LTKA00,
while an LT1025 with a 1 identifier should be used with an LTKA01.
Consult factory for parts specified with wider operating temperature ranges.
ORDER PART NUMBER
KIT
LTK001CN8
LTK001ACN8
LTK001MJ8
LTK001AMJ8
TJMAX = 100°C, θJA = 130°C/W (N8) TJMAX = 150°C, θJA = 150°C/W, θJC = 45°C/W
1
2
3
4
8
7
6
5
TOP VIEW
E
N8 PACKAGE
8-LEAD PDIP
COMPENSATOR
(LT1025)
TJMAX = 150°C, θJA = 100°C/W (J8)
J8 PACKAGE
8-LEAD CERDIP
COMPENSATOR
(LT1025)
VO
10mV/°C
60.9µV/°C
GND
VIN
J
51.7µV/°C
K,T
40.6µV/°C
R,S
6µV/°C
R–
COMMON
ORDER PART NUMBER
AMPLIFIER ONLY
(Note A)
LTKA00CN8
LTKA01CN8
1
2
3
4
8
7
6
5
TOP VIEW
VOS TRIM
–IN
+IN
V–
VOS TRIM
V+
OUT
OVER COMP
N8 PACKAGE
8-LEAD PDIP AMPLIFIER
(LTKA0x)
ORDER PART NUMBER
AMPLIFIER ONLY
(Note A)
LTKA00MH
LTKA01MH
TOP VIEW
V+
VOS TRIM
VOS
TRIM
–IN OUT
OVER COMP
+IN
V–
8
7
6
5
3
2
1
4
H PACKAGE
8-LEAD TO-5 METAL CAN
AMPLIFIER (LTKA0x)
+
–
TJMAX = 100°C, θJA = 130°C/W
Consider the N8 Package for Alternate Source
OBSOLETE PACKAGE OBSOLETE PACKAGE
(Note 1)
Both Devices
Operating Temperature Range
LTK001AMJ8, LTK001MJ8 (OBSOLETE)
......................................................... –55°C to 125°C
LTK001ACN8, LTK001CN8 ...................... 0°C to 70°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature Range (Soldering, 10 sec.)...... 300°C
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LTK001
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TA = 25°C, VS = ±15V (Amplifier), VS = 5V (Compensator)
LTK001A LTK001
PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
Total Temperature Error at 25°C Type E 0.75 2.5 °C
(Note 3) Type J 0.75 2.5 °C
Type K, T 0.86 2.5 °C
Type R, S (Note 12) 5.0 5.0 °C
Slope Error (Notes 4 and 9) 0°C ≤ T
J
≤ 70°C Type E 0.05 0.09 °C/°C
Type J 0.06 0.09 °C/°C
Type K, T 0.07 0.10 °C/°C
Type R, S 0.28 0.32 °C/°C
Total Temperature Error at 0°C ≤ T
J
≤ 70°C Type E 2.0 5 °C
Temperature Extremes (Note 9) Type J 2.1 5 °C
Type K, T 2.6 5.2 °C
Type R, S (Note 12) 16 16 °C
– 55°C ≤ T
J
≤ 125°C Type E 6 8.5 °C
Type J 6 8.5 °C
Type K, T 6.3 9 °C
Type R, S (Note 12) 30 30 °C
Temperature Error Change with 0.1 0.1 °C/V
Supply Voltage (Note 5)
Supply Current 480 900 480 900 µA
ELECTRICAL CHARACTERISTICS
(Matched Amplifier and Compensator)
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LTK001
001fa
COMPENSATOR (LT1025)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Temperature Error at 10mV/°C Output (Note 9) T
J
= 25°C, LTK001A 0.3 0.5 °C
T
J
= 25°C, LTK001 0.5 2.0 °C
Full Temperature Span ●
Temperature Error at Individual Outputs (Note 10) LTK001A: E, J, K, T 0.4 0.75 °C
LTK001A: R, S 0.4 1.5 °C
LTK001: E, J, K, T 0.8 2.4 °C
LTK001: R, S 1.2 3.5 °C
Full Temperature Span ●
Supply Current 4V ≤ V
IN
≤ 36V 80 100 µA
0°C ≤ T
J
≤ 70°C●150 µA
– 55°C ≤ T
J
≤ 125°C●200 µA
Change in Supply Current 4V ≤ V
IN
≤ 36V 0.01 0.05 µA/V
Line Regulation (Note 11) 4V ≤ V
IN
≤ 36V ●0.003 0.02 °C/V
10mV/°C Output
Load Regulation (Note 11) 0 ≤ I
O
≤ 1mA ●0.04 0.2 °C
10mV/°C Output
Divider Impedance E 2.5 kΩ
J 2.1 kΩ
K, T 4.4 kΩ
R, S 3.8 kΩ
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
VS = 5V unless otherwise noted.
(Compensator LT1025)
See Curve on LT1025 Data Sheet
See Curve on LT1025 Data Sheet
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LTK001
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AMPLIFIER (LTKA0x)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Input Offset Voltage 10 35 µV
Input 0ffset Voltage Drift with Temperature (Note 6) ● 0.3 1.5 µV/°C
Input Bias Current 0°C ≤ T
A
≤ 70°C●± 200 ± 600 pA
– 55°C ≤ T
A
≤ 125°C●± 300 ± 1500 pA
Input Bias Current Drift with Temperature (Note 6) 1 5 pA/°C
lnput 0ffset Current 0°C ≤ T
A
≤ 70°C●± 100 ± 500 pA
– 55°C ≤ T
A
≤ 125°C●± 200 ± 700 pA
lnput Offset Current Drift with Temperature (Note 6) ●0.6 4 pA/°C
Large Signal Voltage Gain R
L
= 10kΩ●400 2000 V/mV
Common Mode Rejection Ratio V
CM
= ± 13.5V ●106 130 dB
Power Supply Rejection Ratio ± 2.5V ≤ V
S
≤ ± 20V (Note 5) ●106 125 dB
Common Mode Input Voltage Range Notes 6, 7 Above V
–
0.75 V
Below V
+
1.0 V
Output Voltage Swing (Notes 6, 8) Referred to Supplies I
OUT
= 0.1mA 0.8 V
I
OUT
= 1mA 1.1 V
Supply Current ●400 800 µA
Supply Voltage Range Total V
+
to V
–
Voltage ●4.5 40 V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The inputs of the LTKA0x amplifier are clamped with diodes, so a
differential voltage rating does not apply.
Note 3: Total temperature error is the overall error at 25°C taking into
account the offset of the amplifier, the offset at the compensator 10mV/°C
output, and the error in the compensator divider network. Warmup drift is
not included.
Note 4: Slope error is the increase in total temperature error as ambient
temperature is increased. It is guaranteed by design and by other tests,
but is not tested directly.
Note 5: This is a worst-case limit assuming that any or all supply voltages
change.
Note 6: Guaranteed, but not tested.
Note 7: By referring common mode range to the supplies, the range
referred to ground can be quickly calculated for any given supply voltage.
With a single 5V supply, for instance, which has a worst-case low value of
4.7V, the upper common mode limit is 4.7V – 1V = 3.7V. The lower
common mode limit is 0V + 0.75V = 0.75V. With ±15V supplies, the limits
would be 14V and –14.25V, respectively. Common mode range has a
temperature sensitivity of ≈ 2mV/°C.
Note 8: Absolute output voltage swing is calculated by subtracting the
given limits from actual supply voltage. These limits indicate the point
where offset voltage has changed suddenly by 5µV.
Note 9: Temperature error is defined as the deviation from the following
formula:
V
OUT
= α(T) + α
ß
(T – 25°C)
2
α = Typical thermocouple Seebeck coefficient as follows,
E = 60.9µV/°C, J = 51.7µV/°C, K, T = 40.6µV/°C, R, S = 5.95µV/°C.
α = 10mV/°C at the 10mV output.
ß
= Nonlinearity coefficient built into the LT1025 to help compensate
for the nonlinearities of thermocouples.
ß
= 5.5 x 10
–4
, generating
0.34°C bow for 25°C temperature change, and 1.36°C bow for 50°C
change.
Note 10: Temperature error at the individual outputs is the sum of the
10mV/°C output error plus the resistor divider error.
Note 11: Line and load regulation do not take into account the effects of
self-heating. Output changes due to self-heating can be calculated as
follows:
∆V
OUT
(Line) = ∆V
IN
(I
q
+ I
load
)(150°C/W)
∆V
OUT
(Load) = (∆I
load)
(V
IN
)(150°C/W)
= LT1025 supply current
Load regulation is 30µA ≤ I
O
≤ 1mA for T
A
≤ 0°C.
Note 12: Larger errors with type R and S thermocouples are due mostly to
35µV offset of the amplifier. This error can be reduced to 5µV max with the
LTC®1050 or LTC1052 operational amplifiers.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
VS = ±15V, VCM = 0V, TJ = 25°C unless otherwise noted.
(Amplifier LTKA0x)
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LTK001
001fa
OBSOLETE PACKAGE
U
PACKAGE DESCRIPTIO
.050
(1.270)
MAX
.016 – .021**
(0.406 – 0.533)
.010 – .045*
(0.254 – 1.143)
SEATING
PLANE
.040
(1.016)
MAX .165 – .185
(4.191 – 4.699)
GAUGE
PLANE
REFERENCE
PLANE
.500 – .750
(12.700 – 19.050)
.305 – .335
(7.747 – 8.509)
.335 – .370
(8.509 – 9.398)
DIA
.200
(5.080)
TYP
.027 – .045
(0.686 – 1.143)
.028 – .034
(0.711 – 0.864)
.110 – .160
(2.794 – 4.064)
INSULATING
STANDOFF
45°
H8(TO-5) 0.200 PCD 0204
LEAD DIAMETER IS UNCONTROLLED BETWEEN THE REFERENCE PLANE
AND THE SEATING PLANE
FOR SOLDER DIP LEAD FINISH, LEAD DIAMETER IS .016 – .024
(0.406 – 0.610)
*
**
PIN 1
H Package
8-Lead TO-5 Metal Can (.200 Inch PCD)
(Reference LTC DWG # 05-08-1320)
7
LTK001
001fa
OBSOLETE PACKAGE
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
U
PACKAGE DESCRIPTIO
J8 0801
.014 – .026
(0.360 – 0.660)
.200
(5.080)
MAX
.015 – .060
(0.381 – 1.524)
.125
3.175
MIN
.100
(2.54)
BSC
.300 BSC
(7.62 BSC)
.008 – .018
(0.203 – 0.457) 0° – 15°
.005
(0.127)
MIN
.405
(10.287)
MAX
.220 – .310
(5.588 – 7.874)
1234
87
65
.025
(0.635)
RAD TYP
.045 – .068
(1.143 – 1.650)
FULL LEAD
OPTION
.023 – .045
(0.584 – 1.143)
HALF LEAD
OPTION
CORNER LEADS OPTION
(4 PLCS)
.045 – .065
(1.143 – 1.651)
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
J8 Package
8-Lead CERDIP (Narrow .300 Inch, Hermetic)
(Reference LTC DWG # 05-08-1110)
8
LTK001
001fa
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear-tech.com
LT/LT 0305 REV A • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 2001
U
PACKAGE DESCRIPTIO
N8 1002
.065
(1.651)
TYP
.045 – .065
(1.143 – 1.651)
.130 ± .005
(3.302 ± 0.127)
.020
(0.508)
MIN
.018 ± .003
(0.457 ± 0.076)
.120
(3.048)
MIN
12 34
87 65
.255 ± .015*
(6.477 ± 0.381)
.400*
(10.160)
MAX
.008 – .015
(0.203 – 0.381)
.300 – .325
(7.620 – 8.255)
.325 +.035
–.015
+0.889
–0.381
8.255
()
NOTE:
1. DIMENSIONS ARE INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.100
(2.54)
BSC
PART NUMBER DESCRIPTION COMMENTS
LT1012 Picoamp Input Current Amplifier V
OS
= 120µV MAX, I
OS
= 280pA MAX
LT1025 Thermocouple Cold Junction Comparator Micropower, 0.5°C Initial Accuracy
LTC1050 Zero Drift Amplifier V
OS
= 5µV MAX, A
VOL
= 1V/µV MAX
LTC2050 SOT-23 Zero Drift Amplifier V
OS
= 3µV MAX
RELATED PARTS
N8 Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
