MAX11200 Datasheet, PDF (25/27 Pages) Maxim Integrated Products – 24-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADCs with GPIO

24-Bit, Single-Channel, Ultra-Low-Power,
Delta-Sigma ADCs with GPIO
IREF1 = K x IREF2
IREF2
RREF
IREF1
RRTD
REFP
MAX11200
REFN MAX11210
AINP
AINN
GND
Figure 8. RTD Temperature Measurement Circuit
AVDD
REFP
REFN
MAX11200
AINP MAX11210
AINN
Applications Information
See Figure 8 for the RTD temperature measurement
circuit and Figure 9 for a resistive bridge measurement
circuit.
Magnetic force restoration (MFR) force-measuring (typi-
cally weight) systems are a good design example requir-
ing an ADC that has exceptional dynamic range and lin-
earity. MFR devices use a lever and fulcrum to balance
an unknown weight (the object to be measured) with
an electromagnetic force coil. The current necessary to
keep the balance in equilibrium is equal to the force of
gravity exerted to the object to be weighed.
These currents can be as large as several hundred
amperes, or as small as several microamperes, all in the
same system. Often, it is necessary to maintain the given
accuracy across the entire scale.
This application requires a quantizing device with
enough resolution and dynamic range to match the sen-
sor system. In the past, this was done using an audio
ADC and DAC under the control of a microprocessor to
build a discrete delta-modulator-style A/D. This was very
expensive, and could decrease the mean time between
failure (MTBF) for measurement devices requiring high
reliability. The MAX11200/MAX11210 ADCs offer a much
simpler solution with excellent resolution and dynamic
range. See Figure 10.
PROCESS: BiCMOS
Chip Information
Figure 9. Resistive Bridge Measurement Circuit
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