AM452 – Voltage-to-current transducer IC
with a differential input
FEATURES
•
Instrumentation amplifier input with a
wide voltage range of ±400mV
•
Adjustable gain and offset
•
Adjustable current output
(e.g. of 0/4...20mA)
•
2- and 3-wire operation
•
Suitable for HART
®
applications
•
Protection against reverse polarity and
short-circuiting
•
Output signal limiting
•
Integrated current source
•
Adjustable integrated reference voltage
source of 5 to 10V
•
Modular configuration
•
Supply voltage of 6...35V
•
Temperature range of -40°C...+85°C
•
RoHS compliant
GENERAL DESCRIPTION
AM452 is an integrated transducer with an
adjustable current output which has been
specifically designed for the conditioning of
differential input signals. It permits the
independent adjustment of the offset and full-
scale current using just a few components.
The IC consists of various functional modules. In
addition to the instrumentation amplifier in the
signal path there is an operational amplifier which
is used to set the gain. The offset can be adjusted
using the Zero adjust stage and/or the SET stage
module.
An additional operational amplifier can supply
external components. The adjustable current
output stage permits 2- and 3-wire operation by
way of a simple amendment to the circuitry.
The IC is distinguished by its many protective
functions which include protection against
reverse polarity and short-circuiting and also an
internal current limit.
SCHEMATIC
Prog. Reference
Reference Offset
OP2 Output
1
12
15
16
OP2
Input
Differential
input
voltages
2
V
BG
3
4
SET Stage
11
10
OP2
Voltage Reference
V/I Converter
VCC
Output
9
8
IA
ZERO Stage
13
5
OP1
AM452
7
14
Offset
Amplifier
GND
Figure 1:
Block diagram of AM452
Figure 1:
Schematic of AM452
Phone: +49 (0)6131/91 073-0
Fax:
+49 (0)6131/91 073-30
Internet:
http://www.analogmicro.de
Email: info@analogmicro.de
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
February 2008 - Rev 1.2 - Page 3/21
AME [ ANALOG MICROELECTRONICS ]
