Industrial Converter and Protector IC

AM460

analog microelectronics

April 2003

12/18

R6 and R7:

6

.

1

1

6

.

2

1

7

6

=

−

≈

−

=

BG

CVREF

V

V

R

R

The following example values are produced for the resistors:

R7 = 10kΩ

R6 = 16kΩ

OPERATING AM460: IMPORTANT POINTS TO NOTE

1. When using AM460 it is imperative that external capacitor C1 (a top-grade ceramic capacitor) is always

connected (cf. Figure 2). Care must be taken that the value of the capacitor, also within the temperature

range, does not exceed the range of values given in the boundary conditions on page 6. 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 entire system (AM460 plus all external components, in-

cluding the configuration resistors) must not exceed the sum of IOUTmin (usually 4mA).

3. All AM460 function blocks not required by the application must be connected to a defined (and allowed)

potential.

4. With operation of the voltage output the load resistance at pin VOUT must be at least 2k

Ω.

5. When operating the current output a maximum load resistance of 600

Ω is permitted.

6. 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 6.

APPLICATIONS

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

Figure 7 shows a 3-wire application in which AM460 amplifies and converts a positive voltage signal refer-

enced to ground. The unused blocks (e.g. OP2) have been set to defined operating points. Alternatively, these

function groups can also be used here (e.g. to supply external components).

In this particular application, using Equations 1 and 2 output voltage VOUT is calculated as:

INP

V

OUT

V

G

V

=

with

2

.

2

1

2

1

⋅













+

=

=

R

R

G

G

G

OP

GAIN

V

(14)

For output current IOUT the following applies according to Equation 3:

SET

I

INP

OUT

I

R

G

V

I

+

⋅

=

0

8

with

2

1

1

R

R

G

G

GAIN

I

+

=

=

and

0

=

SET

I