Low Cost Rate Sensor for Automotive Applications — the Fabless Strategy

Abstract

This paper describes the development of a new low cost angular rate sensor (gyro) for automotive applications. The goal of this development has been to produce a manufacturable sensor utilising a MEMS sense element, ASIC, and plastic package. We discuss a new development approach that focuses on product design and characterisation, and utilises an entirely external processing and manufacturing infrastructure.

To achieve the targeted cost, we have taken a systematic approach to evaluating all aspects of the product design and manufacturing to ensure the objective is attainable. Significant tradeoff between gyro design and performance has been made to enhance manufacturing producibility. From sense element design, signal conditioning electronics, to packaging and testing, our systematic approach provided the guideline for design and manufacturing developments.

The initial sense element has been tested using board electronics to +/- 300 degrees/second range yielding a linearity of 0. 4%. The bias stability has been measured as +/- 4 degrees/seconds. Additional improvements are being made to achieve a bias stability of +/- 1 degree/second. Work is now in progress to convert board electronics into an ASIC.