AD590_02 INTERSIL [Intersil Corporation], AD590_02 Datasheet - Page 7

• Manufacturer Part Number: AD590_02
• Description: 2-Wire, Current Output Temperature Transducer
• Manufacturer: INTERSIL [Intersil Corporation]

The AD590 produces a temperature-dependent voltage
across R (C is for filtering noise). Setting R
scale-zero voltage. For the celsius scale, make R = 1kΩ
and V
V
Meter displays current output directly in degrees Kelvin.
using the AD590J, sensor output is within ±10 degrees over
the entire range. See Figure 10.
ALL values are in kΩ.
The ICL7106 has a V
(V+ -0.5V) to (V- +1V). R is scaled to bring each range within
V
500mV maximum rending on the celsius range 199.9
limited by the (short-term) maximum allowable sensor tem-
perature. Maximum reading on the fahrenheit range is
+
-
FIGURE 11. BASIC DIGITAL THERMOMETER, CELSIUS AND
ZERO
CM
n
o
o
∑
R
C
F
5
=
+
-
1
AD590
R
while not exceeding V
ZERO
n
= 0.460V. See Figure 9.
AD590
9.00
5.00
=
R
R
R
R
R
R
1
2
3
4
5
FIGURE 10. SIMPLEST THERMOMETER
28kΩ
FAHRENHEIT SCALES
= 0.273V. For Fahrenheit, R = 1.8kΩ and
nominal
4.02
4.02
R
1
IN
span of ±2.0V and a V
REF HI
REF LO
IN HI
COMMON
IN LO
ICL7106
2.0
2.0
R
2
IN
V+
V
. V
-
12.4
5.11
REF
R
3
for both scales is
10.0
5.0
R
2
4
CM
4V < V
produces a
+
500µA
M
range of
<30V
-
BATT
11.8
R
0
5
AD590
o
C
+
-
7
199.9
See Figure 11 and notes below.
The Kelvin scale version reads from 0 to 1999
theoretically, and from 223
resistor brings the input within the ICL7106 V
general-purpose silicon diodes or an LED may be substi-
tuted. See Figure 12 and notes below.
This circuit allows “zero adjustment” as well as slope
adjustment. the ICL8069 brings the input within the com-
mon-mode range, while the 5kΩ pots trim any offset at
218
notes below.
Notes for Figure 11, Figure 12 and Figure 13
Since all 3 scales have narrow V
of ICL7106 components can be made to lower noise and
FIGURE 13. BASIC DIGITAL THERMOMETER, KELVIN SCALE
FIGURE 12. BASIC DIGITAL THERMOMETER, KELVIN SCALE
+
-
2.26kΩ
1.00kΩ
o
1kΩ
0.1%
ICL8069
1.235V
K (-55
o
F (93.3
12kΩ
402Ω
+
-
5kΩ
7.5kΩ
15kΩ
o
AD590
5kΩ
WITH ZERO ADJUST
C), and set the scale factor. See Figure 13 and
ZERO
ADJ
o
26.1kΩ
AD590
C) limited by the number of display digits.
1.000V
7.5kΩ
SCALE
5kΩ
ADJ
SCALE
ADJ
15kΩ
o
REF HI
REF LO
IN HI
COMMON
IN LO
K to 473
ICL7106
REF HI
REF LO
IN HI
COMMON
IN LO
lN
V+
V
spans, some optimization
ICL7106
-
o
K actually. The 2.26kΩ
V+
V
-
CM
range: 2
o
K