1B21AN Analog Devices Inc, 1B21AN Datasheet - Page 7

• Manufacturer Part Number: 1B21AN
• Description: IC CONV V TO I HYBRID 38-DIP
• Manufacturer: Analog Devices Inc
• Type: Voltage and Current Controllerr

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

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