H28 Datasheet, PDF (9/11 Pages) –

APPLICATION INFORMATION
Figure 3. Resistive sensor connection circuit
Together with a resistive pressure sensor, H28 can
be used in pressure measurement applications.
Control can be performed with a micro-controller
through the I²C serial interface.
The sensor is connected between the power supply
voltage (VDD) and H28 signal ground (COMMON)
which can be internally (switch inside of H28)
connected to ground (GND). Sensor output is read
as a differential signal through PI (positive input) and
NI (negative input) to the converter in H28.
In the pressure measurement mode, the switches
marked “P” are closed and the sensor output is fed
through to the ADC. In the temperature
measurement mode, the switches marked “T” are
closed and the voltage at the ADC input is
determined by the internal resistor array and the
temperature-dependent resistance of the sensor. In
this configuration the sensor bridge is connected as
part of single four resistor bridge circuit where other
four resistors (R1, R2, R3, R4) are inside the IC.
To guarantee conversion accuracy a supply voltage
decoupling capacitor of 4.7 µF or more should be
placed between VDD and GND of H28 (see
CV D D in figure 3).