am452 AME, Inc., am452 Datasheet - Page 12

• Manufacturer Part Number: am452
• Description: Voltage-to-current Transducer Ic With A Differential Input - Analog Microelectronics
• Manufacturer: AME, Inc.

Selecting the supply voltage
"System" supply voltage V
operation. The word "system" here refers to the IC plus its external circuitry.
When using current output pin 8 (IOUT) in conjunction with the external transistor V
dependent on the relevant load resistor R
applicable to the minimum system supply voltage V
Here, I
voltage which is dependent on the selected reference voltage:
For the 3-wire version the load resistance is limited to R
V
Equation 7 is also valid for the 2-wire version; here, however, the R
does not apply. Here, load resistor R
Setting the offset and output current range for V
When adjusting AM452 a preset should first be made. To this end the offset of the output
current is compensated for, in which the two IA inputs are first short-circuited (V
then both set to a permitted potential (c.f. CMIR in ELECTRICAL SPECIFICATIONS). With
the short-circuit at the input the following is derived from Equations (3) and (4) when the
voltage divider from R
for example):
Figure 5: Working range in conjunction with the load
OUT max
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
600
300
R
AM452 – Voltage-to-current transducer IC
L
0
[ ]
OUTmax
0
= 12V @ V
resistor in 3-wire operation
6
stands for the maximum output current and V
R
L
V
CC
S
I
12
OUTmax
V
3
V
V
with a differential input
CCmin
and R
18V.
CC
S
min
S
18
I
needed to operate AM452 is dependent on the selected mode of
OUT
4
Operating range
is taken into account for reference voltage V
V
max
REF
24
R
Lmax
L
1
V
= 900 when V
V
CC
L
min
used by the application. The following is then
35
V
R
I
OUTmax
CCmin
Lmax
S
:
= 6V
= 600
= 20mA
V
S
S
= 24V.
[V]
Lmax
IN
CCmin
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February 2008 - Rev 1.2 - Page 12/21
= 0
= 600 due to the condition:
for the minimum IC supply
In Equation (7) of Figure 5
the ohmic resistance of
power supply lines R
taken into consideration. This
is entered as an additive
quantity (I
calculation of V
(7).
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http://www.analogmicro.de
Lmax
= 600 limitation
REF
OUT max
(see Figure 2,
S
in Equation
R
IN
R
) to the
= 0) and
R
is not
S
(7)
(8)
is