®

ISC300

6

Figure 4 shows the configuration for voltage measurement.

A full scale input range of

±10V can be accepted by the

ISC300. The two sense lines can be connected to give open

or short circuit detection. An open circuit will result in an

output of < –5.1V and a short circuit will give a < 0.1V

output. See the Applications section under Fault Conditions

for more information.

Figure 7 shows a possible circuit configuration using jump-

ers to select voltage or RTD operation.

ISOLATED SUPPLIES

The two isolated supplies available on the input side are

capable of supplying

±11.5V min at 5mA. These can be used

to provide power for external front-end circuitry for addi-

tional signal processing. When using the isolated supplies, it

is necessary to decouple them as close to the device as

possible. 10

µF tantalum capacitors should be used. This will

also improve the signal-to-noise ratio.

FIGURE 3. Resistance Measurement Configuration.

FIGURE 4. Voltage Measurement Configuration.

+V

ISO

Sense 2

–In

+In

Sense 1

Filter and

MUX

Line Resistance

–10V

to

+10V

–V

ISO

Com 1

PGA

20M

Ω

20M

Ω

+V

ISO

I

1

I

2

Sense 2

Com 1

– In

+In

Com 1

I

REF1

I

REF2

–V

ISO

Filter and

MUX

Line Resistance

0

to

500

Ω

Ω

R

S

20M

Ω

PGA