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MAX1358/MAX1359/MAX1360
16-Bit Data-Acquisition Systems with ADC, DACs,
UPIOs, RTC, Voltage Monitors, and Temp Sensor
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The OFFSET CAL register contains the 24-bit data of
the most recently completed offset calibration.
OFFSET<23:0>: Offset-calibration bits. The data format
is two’s complement and is subtracted from the ADC
output before being written to the DATA register. The
offset calibration allows input offset errors between
VREF ±50% to be corrected in unipolar or bipolar mode.
The MAX1358/MAX1359/MAX1360 can perform system
offset calibration or self offset calibration. Self-calibra-
tion performs a calibration for the entire signal path.
See the ADC Calibration section for more details.
The ADC input voltage range specifications must
always be obeyed and the OFFSET CAL register effec-
tively offsets the ADC digital scale to a “zero” value
determined by the calibration.
MSB
OFFSET23
OFFSET22
OFFSET21
OFFSET20
OFFSET19
OFFSET18
OFFSET17
OFFSET16
OFFSET15
OFFSET14
OFFSET13
OFFSET12
OFFSET11
OFFSET10
OFFSET9
OFFSET8
LSB
OFFSET7
OFFSET6
OFFSET5
OFFSET4
OFFSET3
OFFSET2
OFFSET1
OFFSET0
OFFSET CAL Register (Power-On State: 0000 0000 0000 0000 0000 0000)
MSB
GAIN23
GAIN22
GAIN21
GAIN20
GAIN19
GAIN18
GAIN17
GAIN16
GAIN15
GAIN14
GAIN13
GAIN12
GAIN11
GAIN10
GAIN9
GAIN8
LSB
GAIN7
GAIN6
GAIN5
GAIN4
GAIN3
GAIN2
GAIN1
GAIN0
GAIN CAL Register (Power-On State: 1000 0000 0000 0000 0000 0000)
GAIN<23:0>: Gain-calibration bits. The data format is
unsigned binary with 23 bits to the right of the decimal
point and scales the ADC output before being written to
the DATA register. The gain calibration allows full-scale
errors between -VREF / 2 and +VREF / 2 to be corrected
in unipolar mode, and full-scale errors between (+50%
x VREF) and (+200% x VREF) in unipolar or bipolar
mode. The MAX1358/MAX1359/MAX1360 can perform
system gain calibration or self gain calibration. Self-cali-
bration performs a calibration for offsets in the ADC and
system calibration performs a calibration for the entire
signal path. See the ADC Calibration section for more
details.
The ADC input voltage range specifications must always
be obeyed and the GAIN CAL register effectively scales
the ADC digital output to a full-scale value determined
by the calibration. The usable gain-calibration range is
limited to less than the full GAIN CAL register digital-
scaling range by the internal noise of the ADC.