Piezoresistive transducer with low thermal noise

摘要

In a MEMS PRT having a diaphragm that is located offset from the center of the die, thermally-induced thermal noise in the output of a Wheatstone bridge circuit is reduced by locating the Wheatstone bridge circuit away from the largest area of the die and supporting pedestal.

主权项

1. A pressure transducer, comprising:
a substantially parallelepiped-shaped die having top and bottom surfaces and having south, north, west, and east sides, the north and south sides opposing each other, and the east and west sides opposing each other; a plurality of in-line bond pads formed into the top surface along the south side; a diaphragm formed into the bottom surface and responsive to pressure of a fluid; a Wheatstone bridge comprising four piezoresistors formed into the top surface, the four piezoresistors being clustered and located adjacent to a diaphragm edge near the north side, and the four piezoresistors being electrically coupled to the in-line bond pads, whereby all four of the piezoresistors being clustered and located adjacent to a single side of the diaphragm opposite from where the bond pads are located, as opposed to closer to where the bond pads are located, reduces thermally-induced noise that is output by the Wheatstone bridge and that is induced by thermal mismatch caused by bonding a plurality of different types of material together.