MAX1403 Maxim, MAX1403 Datasheet - Page 33

• Manufacturer Part Number: MAX1403
• Description: +3V / 18-Bit / Low-Power / Multichannel / Oversampling Sigma-Delta ADC
• Manufacturer: Maxim

Connect the differential inputs of the MAX1403 to the
bridge network of the strain gauge. In Figure 14, the
analog positive supply voltage powers the bridge net-
work and the MAX1403 along with its reference voltage.
The on-chip PGA allows the MAX1403 to handle an
analog input voltage range as low as 10mV full scale.
The differential inputs of the device allow this analog
input range to have an absolute value anywhere
between AGND and V+.
Figure 14. Strain-Gauge Application with MAX1403
DUMMY
ACTIVE
GAUGE
GAUGE
R
REF
ANALOG SUPPLY
R
R
OUT1
OUT2
AIN1
AIN2
REFIN+
REFIN-
CALIBRATION
______________________________________________________________________________________
ADDITIONAL
CHANNELS
ANALOG
AND
+3V, 18-Bit, Low-Power, Multichannel,
Strain-Gauge Operation
SWITCHING
NETWORK
Oversampling (Sigma-Delta) ADC
AGND
V+
BUFFER
BUFFER
BUFFER
BUFFER
MAX1403
AGND
Figure 15 shows a connection from a thermocouple to
the MAX1403. In this application, the MAX1403 is oper-
ated in its buffered mode to allow large decoupling
capacitors on the front end. These decoupling capaci-
tors eliminate any noise pickup from the thermocouple
leads. When the MAX1403 is operated in buffered
mode, it has a reduced common-mode range. In order
to place the differential voltage from the thermocouple
on a suitable common-mode voltage, the AIN2 input of
the MAX1403 is biased at the reference voltage,
+1.25V.
V+
PGA
DGND
DAC
V
DD
MODULATOR
Temperature Measurement
DIVIDER
INTERFACE
CONTROL
DIGITAL
FILTER
AND
CLOCK
GEN
CLKIN
CLKOUT
SCLK
DIN
DOUT
INT
CS
RESET
DS1
DS0
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