1B21AN Analog Devices Inc, 1B21AN Datasheet - Page 7
1B21AN
Manufacturer Part Number
1B21AN
Description
IC CONV V TO I HYBRID 38-DIP
Manufacturer
Analog Devices Inc
Type
Voltage and Current Controllerr
Datasheet
1.1B21AN.pdf
(8 pages)
Specifications of 1B21AN
Rohs Status
RoHS non-compliant
Full Scale
±50ppm/°C
Linearity
±0.02%
Mounting Type
Through Hole
Package / Case
38-DIP (0.500", 12.70mm), 8 Leads
Ic Function
Voltage To Current Converter IC
Supply Voltage Range
14.25V To 15.75V
Operating Temperature Range
-40°C To +85°C
Digital Ic Case Style
DIP
No. Of Pins
38
Lead Free Status / Rohs Status
Not Compliant
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Price
APPLICATIONS INFORMATION
OUTPUT PROTECTION
In many industrial applications, it may be necessary to protect
the current output from accidental shorts to ac line voltages in
addition to high common-mode voltages and short circuits
to ground. The circuit show in Figure 6 can be used for this
purpose. The maximum permissible load resistance will be
lowered by the fuse resistance (typically 8 Ω) when protection
circuitry is utilized.
REF OUT
LOW DRIFT INPUT NETWORK
Figure 7 shows a configuration suitable for applications where
errors have to be minimized over a wide temperature range. A
temperature tracking network such as a 50 k Beckman (PN 698-
3R50KD) can be used to implement both offset and gain for
either 0 mA to 20 mA or 4 mA to 20 mA current loops. For
0 V to 10 V signals either IN1 or IN2 can be used for input.
For 0 V to 5 V signals, jumper In1 to In2. Similarly, for 4 mA
to 20 mA operation the 4 mA node should be jumpered to
OFFSET, while for 0 mA to 20 mA it should be tied to COM.
INPUT
+15V
COM
–15V
FB
18
17
19
20
21
22
REF
OSCILLATOR
Figure 6. Output Protection Circuitry
1B21
RECTIFIER
38
1
1N4002
V
1N4002
LOOP
50V
0.1µF
1/16A (S.B.)
GE
VARISTOR
V27ZA1
FUSE
R
LOAD
Rev. C | Page 7 of 8
NOTES
1. NODES LABELLED FOR ILLUSTRATION ONLY.
MULTILOOP ISOALTION
Multiple 1B21s can be connected to a single loop supply in
parallel as show in Figure 8. The amperage of the loop supply
should be sufficient to drive all the loops at full-scale output.
OFFSET
COM
4mA
IN2
IN1
1B21
1B21
Figure 7. Low Tempco Resistor Network Configuration
BECKMAN 50kΩ R/N
Figure 8. Multiple 1B21s with Single Loop Supply
38
38
1
1
V
LOOP
24.3kΩ
+15V
1%
COM
–15V
18
17
19
20
21
22
FB
INPUT
REF
OSCILLATOR
1B21
RECTIFIER
R
R
L1
L2
1B21
38
1