Pressure Sensor; Figure 5. Pressure Measurement Schematic Diagram - ST STM32373C-EVAL User Manual

Hardware layout and configuration
2.19

Pressure sensor

An absolute pressure sensor with 1000 HP, full scale MPX2102, and an analog front end is
implemented on the STM32373C-EVAL board. The output differential pair is connected to
the sigma delta ADC in the STM32F373VCT6 via PE8 (P) and PE9 (N).
The principle of the pressure measurement is given in
Figure 5.
The differential voltage, at output, of the amplifier is given in
Equation 9
V V
–
OUT+
where:
●
G represents the operational amplifier differential gain when R3 is infinite.
● G = 2 * R2/R1 + 1
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Pressure measurement schematic diagram
VDD
MPX2102
V
TEMP
R4
( ) × (
V V
= –
OUT- IN+ IN-
Doc ID 023566 Rev 1
VDD
R3
V
IN+
+
-
R1
-
V
IN-
+
R3
⁄ ) VDD ×
G R2 R3
+ –
Figure 5.
R2
R2
MS30570V1
Equation 9.
⁄
R2 R3
UM1564
V
OUT+
V
OUT-