AD594/AD595–SPECIFICATIONS
Model
Min
ABSOLUTE MAXIMUM RATING
+V
S
to –V
S
Common-Mode Input Voltage
Differential Input Voltage
Alarm Voltages
+ALM
–ALM
Operating Temperature Range
Output Short Circuit to Common
TEMPERATURE MEASUREMENT
(Specified Temperature Range
0°C to +50°C)
Calibration Error at +25°C
1
Stability vs. Temperature
2
Gain Error
Nominal Transfer Function
AMPLIFIER CHARACTERISTICS
Closed Loop Gain
3
Input Offset Voltage
Input Bias Current
Differential Input Range
Common-Mode Range
Common-Mode Sensitivity – RTO
Power Supply Sensitivity – RTO
Output Voltage Range
Dual Supply
Single Supply
Usable Output Current
4
3 dB Bandwidth
ALARM CHARACTERISTICS
V
CE(SAT)
at 2 mA
Leakage Current
Operating Voltage at – ALM
Short Circuit Current
POWER REQUIREMENTS
Specified Performance
Operating
5
Quiescent Current (No Load)
+V
S
–V
S
PACKAGE OPTION
TO-116 (D-14)
Cerdip (Q-14)
AD594A
Typ
Max
36
+V
S
+V
S
–V
S
+ 36
+V
S
+125
Min
–V
S
– 0.15
–V
S
–V
S
–V
S
–55
Indefinite
–V
S
– 0.15
–V
S
–V
S
–V
S
–55
Indefinite
(@ +25 C and V
S
= 5 V, Type J (AD594), Type K (AD595) Thermocouple,
unless otherwise noted)
Min
AD595A
Typ
Max
36
+V
S
+V
S
–V
S
+ 36
+V
S
+125
Min
AD595C
Typ
Max
36
+V
S
+V
S
–V
S
+ 36
+V
S
+125
Units
Volts
Volts
Volts
Volts
Volts
°C
AD594C
Typ
Max
36
+V
S
+V
S
–V
S
+ 36
+V
S
+125
–V
S
– 0.15
–V
S
–V
S
–V
S
–55
Indefinite
–V
S
– 0.15
–V
S
–V
S
–V
S
–55
Indefinite
3
0.05
1.5
10
193.4
(Temperature in
°C) ×
51.70
µV/°C
0.1
–10
+50
–V
S
– 0.15
–V
S
– 4
10
10
–V
S
+ 2.5
0
±
5
15
0.3
1
+V
S
– 4
20
+V
S
= 5, –V
S
= 0
+V
S
to –V
S
≤
30
160
100
AD594AD
AD594AQ
300
20
+V
S
– 2
+V
S
– 2
1
0.025
0.75
10
193.4
(Temperature in
°C) ×
51.70
µV/°C
0.1
–V
S
– 0.15
–V
S
– 4
10
10
+V
S
– 2
–V
S
– 2
3
0.05
1.5
10
247.3
(Temperature in
°C) ×
40.44
µV/°C
0.1
–10
+50
–V
S
– 0.15
–V
S
– 4
10
10
–V
S
+ 2.5
0
±
5
15
0.3
+V
S
– 2
+V
S
+ 2
1
0.025
0.75
10
247.3
(Temperature in
°C) ×
40.44
µV/°C
0.1
–10
+50
–V
S
– 0.15
–V
S
– 4
10
10
–V
S
+ 2.5
0
±
5
15
0.3
+V
S
– 2
+V
S
– 2
°C
°C/°C
%
mV/°C
µV
µA
mV
Volts
mV/V
mV/V
Volts
Volts
mA
kHz
Volts
µA
max
Volts
mA
Volts
Volts
–V
S
+ 2.5
0
±
5
15
0.3
1
+V
S
– 4
20
+V
S
= 5, –V
S
= 0
+V
S
to –V
S
≤
30
160
100
AD595AD
AD595AQ
1
+V
S
– 4
20
+V
S
= 5, –V
S
= 0
+V
S
to –V
S
≤
30
300
160
100
AD595CD
AD595CQ
1
+V
S
– 4
+V
S
= 5, –V
S
= 0
+V
S
to –V
S
≤
30
160
100
AD594CD
AD594CQ
300
300
µA
µA
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.
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
–2–
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
REV. C
AD [ ANALOG DEVICES ]
