AD7795 Analog Devices, AD7795 Datasheet - Page 25

• Manufacturer Part Number: AD7795
• Description: 6-Channel, Low Noise, Low Power, 16-Bit Sigma Delta ADC with On-Chip In-Amp and Reference
• Manufacturer: Analog Devices

Specifications of AD7795

• Resolution (bits): 16bit
• # Chan: 6
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (2Vref/PGA Gain) p-p
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

OFFSET REGISTER
RS2, RS1, RS0 = 1, 1, 0; Power-On/Reset = 0x8000
(AD7795), 0x800000 (AD7794))
The offset register is a 16-bit register on the AD7795 and a 24-bit
register on the AD7794. The offset register holds the offset
calibration coefficient for the ADC and its power-on reset value
is 0x8000/0x800000, for the AD7794/AD7795, respectively. The
AD7794/AD7795 each have four offset registers. Channel AIN1
to Channel AIN3 have dedicated offset registers while the
AIN4, AIN5, and AIN6 channels share an offset register. Each
of these registers is a read/write register. The register is used in
conjunction with its associated 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 AD7794/AD7795 must be placed in
power-down mode or idle mode when writing to the offset
register.
Rev. D | Page 25 of 36
FULL-SCALE REGISTER
RS2, RS1, RS0 = 1, 1, 1; Power-On/Reset = 0x5XXX
(AD7795), 0x5XXX00 (AD7794)
The full-scale register is a 16-bit register on the AD7795 and a
24-bit register on the AD7794. The full-scale register holds the
full-scale calibration coefficient for the ADC. The AD7794/
AD7795 each have four full-scale registers. The AIN1, AIN2,
and AIN3 channels have dedicated full-scale registers, while the
AIN4, AIN5, and AIN6 channels share a register. The full-scale
registers are read/write registers. However, when writing to the
full-scale registers, the ADC must be placed in power-down
mode or idle mode. These registers are configured on power-on
with factory calibrated full-scale calibration coefficients, the
calibration being performed at gain = 1. Therefore, every device
has different default coefficients. The coefficients are different,
depending on whether the internal reference or an external
reference is selected. The default value is automatically
overwritten if an internal or system full-scale calibration is
initiated by the user or the full-scale register is written to.
AD7794/AD7795