AD7764 datasheet(20/21 Pages) AD

20 / 21 page

AD7764

Preliminary Technical Data

Rev. PrC | Page 20 of 21

NON BIT-MAPPED REGISTERS

Gain Register (Address 0x0004, 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 gives a

full scale digital output when the input is at 80% of VREF. This ties in with the maximum analog input range of ±80% of VREF Pk-Pk.

Over Range Register (Address 0x0005, Default Value 0xCCCC)

The Over Range register value is compared with the output of the first decimation filter to obtain an overload indication with minimum

propagation delay. This is prior to any gain scaling or offset adjustment. The default value is 0xCCCC which corresponds to 80% of VREF

(the maximum permitted analog input voltage) Assuming VREF = 4.096V, the bit will then be set when the input voltage exceeds

approximately 6.55v pk-pk differential. Note that the over-range bit is also set immediately if the analog input voltage exceeds 100% of

VREF for more than 4 consecutive samples at the modulator rate.

AD7764 Datasheet(PDF) 20 Page - Analog Devices