Datasheet

®
RCV420
9
1
2
3
15
14
V
RCV420
12
13
5
OPA237
O
20kΩ
10
11
C
T
4–20mA
(5–0V)
+6.25V
12kΩ
+10V
+6.25V
R
S
R
S
C
T
1
2
3
RCV420
–In
+In
15
14
12
5
V
O
I
1
I
2
13
R
S
R
S
C
T
1
2
3
RCV420
–In
+In
10
11
12
15
14
13
4–20mA
5
(1)
V
O
(0–5V)
R
S
R
S
C
T
1
2
3
RCV420
–In
+In
10
11
12
15
14
13
5
(N)
V
O
(0–5V)
R
CM
(1)
R
G
(1)
FIGURE 10. Series 4-20mA Receivers.
FIGURE 13. Power Supply Current Monitor Circuit.
FIGURE 12. 4-20mA to 5-0V Conversion.
V
O
= 6.25V – (0.3125) (I
IN
)
NOTE: (1) R
CM
and R
G
are used to provide a first order correction of CMR
and Gain Error, respectively. Table 1 gives typical resistor values for R
CM
and R
G
when as many as three RCV420s are stacked. Table II gives
typical CMR and Gain Error with no correction. Further improvement in
CMR and Gain Error can be achieved using a 500kΩ potentiometer for
R
CM
and a 100Ω potentiometer for R
G
.
RCV420 R
CM
(kΩ)R
G
(Ω)
1
∞ 0
2 200 7
367 23
TABLE 1. Typical Values for R
CM
and R
G
.
TABLE II. Typical CMR and Gain Error
Without Correction.
RCV420 CMR (dB) GAIN ERROR %
1 94 0.025
2 68 0.075
3 62 0.200
FIGURE 11. Differential Current-to-Voltage Converter.
V
O
= 0.3125 (I
1
– I
2
)
Max Gain Error = 0.1% (RCV420BG)
(
I
L MAX
16mA
–1
)
NOTE: (1) R
X
= R
S
/
C
T
15
5
12
13
3
2
1
14
RCV420
+In
+In
Load
Load
Power 
Supply
C
T
15
5
12
13
14
RCV420
–In
I
L
+In
Power
Supply
–40V (max)
+40V (max)
R
X
(1)
R
X
(1)
R
X
(1)
R
X
(1)
R
S
R
S
R
S
R
S
V
O

(0-5V)
V
O

(0-5V)
I
L