AD594/AD595
Table I. Output Voltage vs. Thermocouple Temperature (Ambient +25°C, V
S
= –5 V, +15 V)
Thermocouple
Temperature
°C
–200
–180
–160
–140
–120
–100
–80
–60
–40
–20
–10
0
10
20
25
30
40
50
60
80
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
Type J
Voltage
mV
–7.890
–7.402
–6.821
–6.159
–5.426
–4.632
–3.785
–2.892
–1.960
–.995
–.501
0
.507
1.019
1.277
1.536
2.058
2.585
3.115
4.186
5.268
6.359
7.457
8.560
9.667
10.777
11.887
12.998
14.108
15.217
16.325
17.432
18.537
19.640
20.743
21.846
22.949
24.054
25.161
26.272
AD594
Output
mV
–1523
–1428
–1316
–1188
–1046
–893
–729
–556
–376
–189
–94
3.1
101
200
250
300
401
503
606
813
1022
1233
1445
1659
1873
2087
2302
2517
2732
2946
3160
3374
3588
3801
4015
4228
4441
4655
4869
5084
Type K
Voltage
mV
–5.891
–5.550
–5.141
–4.669
–4.138
–3.553
–2.920
–2.243
–1.527
–.777
–.392
0
.397
.798
1.000
1.203
1.611
2.022
2.436
3.266
4.095
4.919
5.733
6.539
7.338
8.137
8.938
9.745
10.560
11.381
12.207
13.039
13.874
14.712
15.552
16.395
17.241
18.088
18.938
19.788
AD595
Output
mV
–1454
–1370
–1269
–1152
–1021
–876
–719
–552
–375
–189
–94
2.7
101
200
250
300
401
503
605
810
1015
1219
1420
1620
1817
2015
2213
2413
2614
2817
3022
3227
3434
3641
3849
4057
4266
4476
4686
4896
Thermocouple
Temperature
°C
500
520
540
560
580
600
620
640
660
680
700
720
740
750
760
780
800
820
840
860
880
900
920
940
960
980
1000
1020
1040
1060
1080
1100
1120
1140
1160
1180
1200
1220
1240
1250
Type J
Voltage
mV
27.388
28.511
29.642
30.782
31.933
33.096
34.273
35.464
36.671
37.893
39.130
40.382
41.647
42.283
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
AD594
Output
mV
5300
5517
5736
5956
6179
6404
6632
6862
7095
7332
7571
7813
8058
8181
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
Type K
Voltage
mV
20.640
21.493
22.346
23.198
24.050
24.902
25.751
26.599
27.445
28.288
29.128
29.965
30.799
31.214
31.629
32.455
33.277
34.095
34.909
35.718
36.524
37.325
38.122
38.915
39.703
40.488
41.269
42.045
42.817
43.585
44.439
45.108
45.863
46.612
47.356
48.095
48.828
49.555
50.276
50.633
AD595
Output
mV
5107
5318
5529
5740
5950
6161
6371
6581
6790
6998
7206
7413
7619
7722
7825
8029
8232
8434
8636
8836
9035
9233
9430
9626
9821
10015
10209
10400
10591
10781
10970
11158
11345
11530
11714
11897
12078
12258
12436
12524
thermocouples Table I should not be used in conjunction with
European standard thermocouples. Instead the transfer function
given previously and a DIN thermocouple table should be used.
ANSI type K and DIN N
I
C
R
-N
I
thermocouples are composed
CONSTANTAN
(ALUMEL)
14
13
SINGLE AND DUAL SUPPLY CONNECTIONS
+5V
12
11
10
9
10mV/ C
8
The AD594/AD595 is a completely self-contained thermocouple
conditioner. Using a single +5 V supply the interconnections
shown in Figure 1 will provide a direct output from a type J
thermocouple (AD594) or type K thermocouple (AD595) mea-
suring from 0°C to +300°C.
Any convenient supply voltage from +5 V to +30 V may be
used, with self-heating errors being minimized at lower supply
levels. In the single supply configuration the +5 V supply con-
nects to Pin 11 with the V– connection at Pin 7 strapped to
power and signal common at Pin 4. The thermocouple wire in-
puts connect to Pins 1 and 14 either directly from the measuring
point or through intervening connections of similar thermo-
couple wire type. When the alarm output at Pin 13 is not used it
should be connected to common or –V. The precalibrated feed-
back network at Pin 8 is tied to the output at Pin 9 to provide a
10 mV/°C nominal temperature transfer characteristic.
By using a wider ranging dual supply, as shown in Figure 2, the
AD594/AD595 can be interfaced to thermocouples measuring
both negative and extended positive temperatures.
–3–
OVERLOAD
DETECT
AD594/
AD595
G
G
+A
ICE
POINT
COMP. –TC
+TC
IRON
(CHROMEL)
1
2
3
4
5
6
7
COMMON
Figure 1. Basic Connection, Single Supply Operation
of identical alloys and exhibit similar behavior. The upper tem-
perature limits in Table I are those recommended for type J and
type K thermocouples by the majority of vendors.
REV. C
AD [ ANALOG DEVICES ]
