Pressure Sensor Chip with New Electrical Circuit for 10 kPa Range

TL;DR

This paper introduces a high-sensitivity MEMS pressure sensor chip operating up to 10 kPa, featuring a novel electrical circuit with a differential amplifier and bipolar transistors, achieving high sensitivity and low nonlinearity.

Contribution

The paper presents a new electrical circuit design for MEMS pressure sensors using a differential amplifier with negative feedback based on bipolar transistors, enhancing sensitivity and linearity.

Findings

Sensitivity of 7.8 to 12.4 mV/V/kPa achieved

Nonlinearity of 0.14% to 0.38% of full scale

Sensor chip size of 4.0x4.0 mm²

Abstract

Characteristics of high sensitivity MEMS pressure sensor chip for 10 kPa utilizing a novel electrical circuit are presented. The electrical circuit uses piezosensitive differential amplifier with negative feedback loop (PDA-NFL) based on two bipolar-junction transistors (BJT). The BJT has a vertical structure of n-p-n type (V-NPN) formed on a non-deformable chip area. The circuit contains eight piezoresistors located on a profiled membrane in the areas of maximum mechanical stresses. The experimental results prove that pressure sensor chip PDA-NFL with 4.0x4.0 mm2 chip area has sensitivity S = 7.8...12.4 mV/V/kPa with nonlinearity of 2KNL = 0.14...0.38 %/FS (pressure is applied from the back side of pressure sensor chip).