Datasheet

Industrial V/I Converter and Protector IC
AM462
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz Oktober 2007 – Rev.2.5 -Page 13/20
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.de
32.4
V1
mA20
2788
0
≈⋅Ω⋅==
INP
OUT
GAIN
V
I
RG ⇒
32.3132.4
2
1
=−=
R
R
Observing the boundary conditions the following values are obtained for the external components:
R
1
≈ 33.2kΩ R
2
= 10kΩ R
0
= 27Ω R
5
= 39Ω R
L
= 0...600Ω C
1
= 2.2µF
Typical 2-wire application with an input signal referenced to ground
In a 2-wire version (cf. Figure 8) system supply voltage V
S
is connected up to pin 11 (RS+) and pin
10 (VCC) to pin9 (RS-). The ground of the IC at pin14 (GND) is connected to the node between
resistor R
5
and load resistor R
L
. IC ground (GND) is not the same as system ground (Ground). The
output signal is picked up via load resistor R
L
which connects current output I
OUT
to the system
ground.
It must be ensured that in 2-wire operation an additional current load (use of current/voltage source)
is limited to 4mA due to the domestic current supply and limitation.
For output current I
OUT
the following applies according to Equations (1) (2) and (4):
SET
Gain
INPOUT
I
R
G
VI +⋅=
0
8
with
2
1
1
R
R
GG
GAINI
+== and
43
4
0
2 RR
R
R
V
I
REF
SET
+
⋅=
Ground
R
5
R
L
1
Single-ended
input voltage
Connections setting unused function blocks to a defined operating point
3-wire connection
1
2
AM462
OP2
R
1
R
2
4
OP1
5
3
Vol ta ge Ref er enc e
R
0
14
6
13
11
8
9
10
V
I
T
1
D
1
C
1
15
16
I
SET
= 0
V
IN P
V
S
I
OUT
V
BG
Figure 7: Typical application for input signals referenced to ground