ES5106

3 1/2 DIGIT A/D CONVERTER W/LCD

03/05/14

9

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Operation Mode

Analog Common

The Common pin is used to set the common-mode voltage for

the system in which the input signals are floating with respect to the

power supply of the ES5106. In all most of the applications, IN LO,

REF LO and COMMON pins are tied to the same point, so that the

common mode voltage can be removed from the reference system

and the converter. In some applications, IN LO may not at the same

point with COMMON and thus a common mode voltage exists in

the system, the high CMRR (86db typical) of the ES 5106 can take

care of this common mode voltage. Neverthereless, it should be care

to prevent the output of the integrator from saturation.

The COMMON pin is also used as a voltage reference. It sets a

voltage which is around 2.9 volts more negative than the positive

supply. The COMMON voltage of ES5106 has a 0.001 %/% voltage

coefficient and a low output impedance of 15Ω typical.

The analog COMMON is tied internally to an N channel FET

capable of sinking 30mA. This FET will hold the COMMON

voltage at 2.9 volts when an external load attempt to pull the

COMMON voltage toward the positive supply.