ZXCT1080 datasheet(8/12 Pages) ZETEX

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ZXCT1080

Issue 1 - November 2007

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Application information

The ZXCT1080 has been designed to allow it to operate with 5V supply rails while sensing

common mode signals up to 60V. This makes it well suited to a wide range of industrial and power

supply monitoring applications that require the interface to 5V systems while sensing much

higher voltages.

To allow this its VCC pin can be used independently of S+.

Figure 1 shows the basic configuration of the ZXCT1080.

Figure 1

Typical configuration of ZXCT1080

Load current from the input is drawn through RSENSE developing a voltage VSENSE across the

inputs of the ZXCT1080.

The internal amplifier forces VSENSE across internal resistance RGT causing a current to flow

through MOSFET M1. This current is then converted to a voltage by RG. A ratio of 10:1 between

RG and RGT creates the fixed gain of 10. The output is then buffered by the unity gain buffer.

The gain equation of the ZXCT1080 is:

The maximum recommended differential input voltage, VSENSE, is 150mV; it will however

withstand voltages up to 800m . This can be increased further by the inclusion of a resistor, RLIM,

between S- pin and the load; typical value is of the order of 10k .

ZXCT1080

OUT

GND

VCC

R GT

R G

R SENSE

Input

Load

S+

S-

A2+1

OUT

LRSENSE

----------

SENSE

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