Datasheet

AD594/AD595–SPECIFICATIONS
REV. B
–2–
Model AD594A AD594C AD595A AD595C
Min Typ Max Min Typ Max Min Typ Max Min Typ Max Units
ABSOLUTE MAXIMUM RATING
+V
S
to –V
S
36 36 36 36 Volts
Common-Mode Input Voltage –V
S
– 0.15 +V
S
–V
S
– 0.15 +V
S
–V
S
– 0.15 +V
S
–V
S
– 0.15 +V
S
Volts
Differential Input Voltage –V
S
+V
S
–V
S
+V
S
–V
S
+V
S
–V
S
+V
S
Volts
Alarm Voltages
+ALM –V
S
–V
S
+ 36 –V
S
–V
S
+ 36 –V
S
–V
S
+ 36 –V
S
–V
S
+ 36 Volts
–ALM –V
S
+V
S
–V
S
+V
S
–V
S
+V
S
–V
S
+V
S
Volts
Operating Temperature Range –55 +125 –55 +125 –55 +125 –55 +125 °C
Output Short Circuit to Common Indefinite Indefinite Indefinite Indefinite
TEMPERATURE MEASUREMENT
(Specified Temperature Range
0°C to +50°C)
Calibration Error at +25°C
1
63 61 63 61 °C
Stability vs. Temperature
2
60.05 60.025 60.05 60.025 °C/°C
Gain Error 61.5 60.75 61.5 60.75 %
Nominal Transfer Function 10 10 10 10 mV/°C
AMPLIFIER CHARACTERISTICS
Closed Loop Gain
3
193.4 193.4 247.3 247.3
Input Offset Voltage (Temperature in °C) × (Temperature in °C) × (Temperature in °C) × (Temperature in °C) ×
51.70 µV/°C 51.70 µV/°C 40.44 µV/°C 40.44 µV/°C µV
Input Bias Current 0.1 0.1 0.1 0.1 µA
Differential Input Range –10 +50 –10 +50 –10 +50 mV
Common-Mode Range –V
S
– 0.15 –V
S
– 4 –V
S
– 0.15 –V
S
– 4 –V
S
– 0.15 –V
S
– 4 –V
S
– 0.15 –V
S
– 4 Volts
Common-Mode Sensitivity – RTO 10 10 10 10 mV/V
Power Supply Sensitivity – RTO 10 10 10 10 mV/V
Output Voltage Range
Dual Supply –V
S
+ 2.5 +V
S
– 2 –V
S
+ 2.5 +V
S
– 2 –V
S
+ 2.5 +V
S
– 2 –V
S
+ 2.5 +V
S
– 2 Volts
Single Supply 0 +V
S
– 2 0 –V
S
– 2 0 +V
S
+ 2 0 +V
S
– 2 Volts
Usable Output Current
4
±5 ±5 ±5 ±5mA
3 dB Bandwidth 15 15 15 15 kHz
ALARM CHARACTERISTICS
V
CE(SAT)
at 2 mA 0.3 0.3 0.3 0.3 Volts
Leakage Current 61 61 61 61 µA max
Operating Voltage at – ALM +V
S
– 4 +V
S
– 4 +V
S
– 4 +V
S
– 4 Volts
Short Circuit Current 20 20 20 20 mA
POWER REQUIREMENTS
Specified Performance +V
S
= 5, –V
S
= 0 +V
S
= 5, –V
S
= 0 +V
S
= 5, –V
S
= 0 +V
S
= 5, –V
S
= 0 Volts
Operating
5
+V
S
to –V
S
≤ 30 +V
S
to –V
S
≤ 30 +V
S
to –V
S
≤ 30 +V
S
to –V
S
≤ 30 Volts
Quiescent Current (No Load)
+V
S
160 300 160 300 160 300 160 300 µA
–V
S
100 100 100 100 µA
PACKAGE OPTION
TO-116 (D-14) AD594AD AD594CD AD595AD AD595CD
Cerdip (Q-14) AD594AQ AD594CQ AD595AQ AD595CQ
NOTES
1
Calibrated for minimum error at +25°C using a thermocouple sensitivity of 51.7 µV/°C. Since a J type thermocouple deviates from this straight line approximation,
the AD594 will normally read 3.1 mV when the measuring junction is at 0°C. The AD595 will similarly read 2.7 mV at 0°C.
2
Defined as the slope of the line connecting the AD594/AD595 errors measured at 0°C and 50°C ambient temperature.
3
Pin 8 shorted to Pin 9.
4
Current Sink Capability in single supply configuration is limited to current drawn to ground through a 50 kΩ resistor at output voltages below 2.5 V.
5
–V
S
must not exceed –16.5 V.
Specifications shown in boldface are tested on all production units at final electrical test. Results from those tests are used to calculate outgoing quality levels. All min and max specifications
are guaranteed, although only those shown in boldface are tested on all production units.
Specifications subject to change without notic
e.
(@ + 258C and V
S
= 5 V, Type J (AD594), Type K (AD595) Thermocouple,
unless otherwise noted)
INTERPRETING AD594/AD595 OUTPUT VOLTAGES
To achieve a temperature proportional output of 10 mV/°C and
accurately compensate for the reference junction over the rated
operating range of the circuit, the AD594/AD595 is gain trimmed
to match the transfer characteristic of J and K type thermocouples
at 25°C. For a type J output in this temperature range the TC is
51.70 µV/°C, while for a type K it is 40.44 µV/°C. The resulting
gain for the AD594 is 193.4 (10 mV/°C divided by 51.7 µV/°C)
and for the AD595 is 247.3 (10 mV/°C divided by 40.44 µV/°C).
In addition, an absolute accuracy trim induces an input offset to
the output amplifier characteristic of 16 µV for the AD594 and
11 µV for the AD595. This offset arises because the AD594/
AD595 is trimmed for a 250 mV output while applying a 25°C
thermocouple input.
Because a thermocouple output voltage is nonlinear with respect
to temperature, and the AD594/AD595 linearly amplifies the
compensated signal, the following transfer functions should be
used to determine the actual output voltages:
AD594 output = (Type J Voltage + 16 µV) × 193.4
AD595 output = (Type K Voltage + 11 µV) × 247.3 or conversely:
Type J voltage = (AD594 output/193.4) – 16 µV
Type K voltage = (AD595 output/247.3) – 11 µV
Table I lists the ideal AD594/AD595 output voltages as a func-
tion of Celsius temperature for type J and K ANSI standard
thermocouples, with the package and reference junction at
25°C. As is normally the case, these outputs are subject to cali-
bration, gain and temperature sensitivity errors. Output values
for intermediate temperatures can be interpolated, or calculated
using the output equations and ANSI thermocouple voltage
tables referred to zero degrees Celsius. Due to a slight variation
in alloy content between ANSI type J and DIN F
E -C U N I