Industrial V/I Converter and Protector IC

AM462

Analog Microelectronics GmbH

An der Fahrt 13, D – 55124 Mainz

Oktober 2007 – Rev.2.5 -Page 12/20

Phone: +49 (0)6131/91 073-0

Fax: +49 (0)6131/91 073-30

Internet:

http://www.analogmicro.de

Email: info@analogmicro.de

POINTS TO NOTE: INITIAL OPERATION OF AM462

1. When operating AM462 it is imperative that external capacitor C1 is always connected (cf.

Figure 2). Care must be taken that the value of the capacitance does not lie beyond its given

range, even across the range of temperature (see Boundary Conditions on page 7). In 2-wire

operation ceramic capacitor C2 must also be used (cf. Figure 8).

2. In a 2-wire setup the power consumption of the overall system (AM462 plus all external

components, including the configuration resistors) must not exceed the sum of IOUTmin (usually

4mA).

3. All AM462 function blocks not required by the application must be connected to a defined (and

allowed) potential.

4. A load resistance of 600

Ω maximum is permitted for the current output.

5. The values of external resistors R0, R1, R2, R3, R4 and R5 must be selected within the permissible

range given in the boundary conditions on page 7.

APPLICATIONS

Typical 3-wire application with an input signal referenced to ground

Figure 7 shows a 3-wire application in which AM462 amplifies and converts a positive voltage

signal referenced to ground. The unused blocks (e.g. OP2) have been set to defined operating points

in the application. Alternatively, these function groups can also be used here (e.g. to supply external

components).

For output current IOUT the following applies according to Equations (1) and (2):

SET

GAIN

INP

OUT

I

R

G

V

I

+

⋅

=

0

8

with

2

1

1

R

R

G

GAIN

+

=

Example: 0…20mA Voltage-To-Current Converter

To convert a signal of VINP = 0...1V at the OP1 input the external components are to be dimensioned

in such a way that the output current has a range of 0...20mA (i.e. ISET = 0 ⇒ SET = GND). With

R0 = 27Ω:

0

0

8

8

R

G

V

I

R

G

V

I

GAIN

INP

SET

GAIN

INP

OUT

⋅

=

+

⋅

=

The following then applies to the gain: