Datasheet

15
Figure 21. 4 to 20 mA HCNR200 receiver circuit.
Figure 22. 4 to 20 mA HCNR200 transmitter circuit.
-
+
V
OUT
-
+
HCNR200 fig 21
V
CC
5.5 V
R1
10 kΩ
+ILOOP
HCNR200
PD1
-ILOOP
R2
10 kΩ
R4
100 Ω
2N3906
Z1
5.1 V
0.1 µF
R3
25 Ω
0.001 µF
R5
80 kΩ
LM158
HCNR200
PD2
0.001 µF
2
HCNR200
LED
LM158
+
-
HCNR200 fig 22
V
CC
R3
10 kΩ
+ILOOP
HCNR200
PD2
-ILOOP
R4
10 kΩ
R6
140 Ω
2N3904
Z1
5.1 V
0.1 µF
R7
3.2 kΩ
0.001 µF
R1
80 kΩ
LM158
HCNR200
PD1
0.001 µF
1
R8
100 kΩ
V
IN
V
CC
5.5 V
R2
150 Ω
HCNR200
LED
2N3906
2N3904
2N3904
R5
25 Ω
LM158
-
+
DESIGN EQUATIONS:
VOUT / ILOOP = K3 (R5 R3) / R1 + R3)
K3 = K2 / K1 = CONSTANT = 1
NOTE: THE TWO OP‑AMPS SHOWN ARE TWO SEPARATE LM158, AND NOT TWO CHANNELS IN A SINGLE
DUAL PACKAGE, OTHERWISE THE LOOP SIDE AND OUTPUT SIDE WILL NOT BE PROPERLY ISOLATED.
DESIGN EQUATIONS:
(ILOOP / VIN) = K3 (R5 + R3) / R5 R1)
K3 = K2 / K1 = CONSTANT = 1
NOTE: THE TWO OP‑AMPS SHOWN ARE TWO SEPARATE LM158, AND NOT TWO CHANNELS IN A SINGLE
DUAL PACKAGE, OTHERWISE THE LOOP SIDE AND OUTPUT SIDE WILL NOT BE PROPERLY ISOLATED.