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 9/20
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http://www.analogmicro.de
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.de
()
43
4
0
2
0
RR
R
R
V
IVI
REF
SETINDAIOUT
+
⋅===
(4)
and thus for the ratio of the resistors R
3
/R
4
:
1
2
04
3
−=
SET
REF
IR
V
R
R
(5)
The output current range is set in conjunction with the selected external resistors R
1
and R
2
(or fine
adjustment with R
0
). Using Equations 1 and 2 the following is calculated for output current I
OUT
:
SET
GAIN
INPOUT
I
R
G
VI +=
0
8
with
2
1
1
R
R
G
GAIN
+=
(6)
Selecting the supply voltage
System supply voltage V
S
needed to operate AM462 is dependent on the selected mode of
operation.
When using current output pin IOUT (in conjunction with the external transistor) the value of V
S
is
dependent on that of the relevant load resistor R
L
(max. 600Ω) used by the application. The
minimum system supply voltage V
S
is then:
minmax CCLOUTS
VRIV +≥ (7)
Here, I
OUTmax
stands for the maximum output current and V
CCmin
for the minimum IC supply voltage
which is dependent on the selected reference voltage:
V1
min
+
≥
REFCC
VV (8)
V
S
[V]
R
L
[Ω
]
6
35
V
CC min
= 6V
R
Lmax
= 600Ω
I
OUTmax
= 20mA
18
2412
600
Working range
0
300
0
R
VV
I
L
SCCmin
OUTmax
−
Figure 4: Working range in conjunction with the load resistor