AD7764 datasheet(33/34 Pages) AD

33 / 34 page

AD7764

Data Sheet

Rev. B | Page 32 of 33

GAIN REGISTER—ADDRESS 0x0004

Nonbit Mapped, Default Value: 0xA000

The gain register is scaled such that 0x8000 corresponds to a

gain of 1.0. The default value of this register is 1.25 (0xA000).

This value results in a full-scale digital output when the input is

at 80% of VREF+, tying in with the maximum analog input range

of ±80% of VREF+ p-p.

OVERRANGE REGISTER—ADDRESS 0x0005

Nonbit Mapped, Default Value: 0xCCCC

The overrange register value is compared to the output of the

first decimation filter to obtain an overload indication with

minimum propagation delay. This comparison is prior to any

gain scaling. The default value is 0xCCCC, which corresponds

to 80% of VREF+ (the maximum permitted analog input voltage).

Assuming VREF+ = 4.096 V, the bit is then set when the input

voltage exceeds approximately 6.55 V p-p differential. The over-

range bit is set immediately if the analog input voltage exceeds

100% of VREF+ for more than four consecutive samples at the

modulator rate.

AD7764 Datasheet(PDF) 33 Page - Analog Devices