MAX110 Datasheet, PDF (16/24 Pages) Maxim Integrated Products – Low-Cost, 2-Channel, ±14-Bit Serial ADCs

Low-Cost, 2-Channel, ±14-Bit Serial ADCs
Table 2. Allowable Input Multiplexer Configurations
CAL NUL CHS NO-OP ADC IN+ ADC IN-
DESCRIPTION
000
1
IN1+
IN1- Channel 1 connected to ADC inputs. Conversion begins when CS returns high.
001
010
011
11X
10X
XXX
X = Don't Care
1
IN2+
IN2- Channel 2 connected to ADC inputs. Conversion begins when CS returns high.
1
IN1-
IN1-
IN1- connected to the ADC inputs; offset-null mode selected. Autonull conversion
begins when CS returns high, and the results are stored in the null register.
1
IN2-
IN2-
IN2- connected to the ADC inputs; offset-null mode selected. Autonull conversion
begins when CS returns high, and the results are stored in the null register.
1
REF-
REF-
REF- connected to the ADC inputs; offset-null mode selected. Autonull conversion
begins when CS returns high, and the results are stored in the null register.
REF+ and REF- connected to the ADC inputs; gain-calibration mode
1
REF+ REF- selected. Autocal conversion begins when CS returns high, and the results are
stored in the 16-bit I/O register.
0
No
Change
No
Change
Input control word is not transferred to the control register. ADC
configuration remains unchanged and no new conversion starts when CS
returns high.
Table 3. Procedure to Calibrate the ADC
STEP
DESCRIPTION
Sets the new conversion speed (if required)
and performs an offset correction conversion
1
with the internal ADC inputs shorted to REF-.
The result is stored in the null register.
(This step also selects the speed/resolution
for the ADC.)
CONTROL WORD
NO-OP
Not
Used
CONV1- DV2 &
CONV4 DV4
Not
Used
CHS
CAL
NUL
PDX
PD
1
00
New
Data
XX
00
X
1
1
0
0
Performs a gain-calibration conversion with
2 the null register contents as the starting value. 1
The result is stored in the calibration register.
00
No
Change
XX
00
X
1
0
0
0
Performs an offset-null conversion with the
internal ADC inputs shorted to the selected
3 input channel's negative input (IN1- or IN2-).
The next operation performs the first signal
1
00
No
Change
XX
0
00 or
1
0
1
0
0
conversion with the new setup.
X = Don't Care
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