ltk001 Linear Technology Corporation, ltk001 Datasheet - Page 5

• Manufacturer Part Number: ltk001
• Description: Thermocouple Cold Junction Compensator And Matched Amplifier
• Manufacturer: Linear Technology Corporation

PARAMETER
Input Offset Voltage
Input 0ffset Voltage Drift with Temperature
Input Bias Current
Input Bias Current Drift with Temperature
lnput 0ffset Current
lnput Offset Current Drift with Temperature
Large Signal Voltage Gain
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Common Mode Input Voltage Range
Output Voltage Swing (Notes 6, 8)
Supply Current
Supply Voltage Range
ELECTRICAL CHARACTERISTICS
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.
The
V
S
= ±15V, V
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
CM
= 0V, T
J
= 25°C unless otherwise noted.
CONDITIONS
(Note 6)
0°C ≤ T
– 55°C ≤ T
(Note 6)
0°C ≤ T
– 55°C ≤ T
(Note 6)
R
V
± 2.5V ≤ V
Notes 6, 7
Referred to Supplies
Total V
CM
L
= 10kΩ
= ± 13.5V
+
A
A
to V
≤ 70°C
≤ 70°C
(Amplifier LTKA0x)
S
A
A
≤ ± 20V (Note 5)
≤ 125°C
≤ 125°C
–
Voltage
Above V
Below V
I
I
Note 9: Temperature error is defined as the deviation from the following
formula:
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:
Load regulation is 30µA ≤ I
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
OUT
OUT
V
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
0.34°C bow for 25°C temperature change, and 1.36°C bow for 50°C
change.
∆V
∆V
®
= 0.1mA
= 1mA
OUT
1050 or LTC1052 operational amplifiers.
OUT
OUT
+
–
= α(T) + α ß (T – 25°C)
(Line) = ∆V
(Load) = (∆I
= LT1025 supply current
IN
load)
(I
●
●
●
●
●
●
●
●
●
●
●
q
(V
+ I
O
IN
≤ 1mA for T
load
)(150°C/W)
MIN
0.75
400
106
106
4.5
2
)(150°C/W)
AMPLIFIER (LTKA0x)
A
≤ 0°C.
± 200
± 300
± 100
± 200
2000
130
125
400
TYP
0.6
0.8
1.1
10
0.3
1
± 1500
± 600
± 500
± 700
–4
MAX
800
1.0
1.5
40
35
4
, generating
5
LTK001
A
= 25°C.
UNITS
µV/°C
pA/°C
pA/°C
V/mV
5
001fa
µV
pA
pA
pA
pA
dB
dB
µA
V
V
V
V
V