AD7796/AD7797

Rev. A | Page 15 of 24

OFFSET REGISTER

RS2, RS1, RS0 = 1, 1, 0; Power-On/Reset = 0x8000 (AD7796)/0x800000 (AD7797)

The analog input channel has an offset register that holds the offset calibration coefficient for the channel. This register is 16 bits wide on

the AD7796 and 24 bits wide on the AD7797, and its power-on/reset value is 0x8000(00). The offset register is used in conjunction with

the full-scale register to form a register pair. The power-on/reset value is automatically overwritten if an internal or system zero-scale

calibration is initiated by the user. The offset register is a read/write register. However, the AD7796/AD7797 must be in idle mode or

power-down mode when writing to this register.

FULL-SCALE REGISTER

RS2, RS1, RS0 = 1, 1, 1; Power-On/Reset = 0x5XXX (AD7796)/0x5XXX00 (AD7797)

The full-scale register is a 16-bit register on the AD7796 and a 24-bit register on the AD7797. The full-scale register holds the full-scale

calibration coefficient for the ADC. The full-scale register is a read/write register. However, when writing to the full-scale register, the

ADC must be placed in power-down mode or idle mode. The full-scale register is configured on power-on with the factory-calibrated

full-scale calibration coefficient. Therefore, every device has a different default coefficient. The default value is automatically overwritten

if a system full-scale calibration is initiated by the user, or if the full-scale register is written to.