Datasheet

MAX11359A
16-Bit Data-Acquisition System with ADC, DAC,
UPIOs, RTC, Voltage Monitors, and Temp Sensor
38
Maxim Integrated
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
V
REF
±50% to be corrected in unipolar or bipolar mode.
The MAX11359A can perform system offset calibration
or self offset calibration. Self-calibration performs a cali-
bration 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
ADC15 ADC14 ADC13 ADC12 ADC11 ADC10 ADC9 ADC8
LSB
ADC7 ADC6 ADC5 ADC4 ADC3 ADC2 ADC1 ADC0
DATA Register (Power-On State: 0000 0000 0000 0000)
ADC<15:0> Analog-to-digital conversion data bits.
These 16 bits are the results from the most recently
completed conversion. The data format is unsigned;
binary for unipolar mode, and two’s complement for
bipolar mode.
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 -V
REF
/2 and +V
REF
/2 to be corrected in
unipolar mode, and full-scale errors between (+50% x
V
REF
) and (+200% x V
REF
) in unipolar or bipolar mode.
The MAX11359A can perform system gain calibration
or self gain calibration. Self-calibration performs a cali-
bration 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.