We have developed a 15-Gbit/s 96-gate Si-bipolar gate array using 0.5-µm Si-bipolar technology, a sophisticated internal cell design, an I/O buffer design suitable for high-speed operation and high-frequency package technology. The decision circuit and 4 : 1 multiplexer fabricated on the gate array operate up to 15-Gbit/s and above 10-Gbit/s respectively. The data input sensitivity and the phase margin of the decision circuit are 53 mVpp and 288 at 10-Gbit/s operation. This gate array promises to be useful in shortening the development period and lowering cost of 10-Gbit/s class IC's.

This paper describes an adaptive fingerprint-sensing scheme for a user authentication system with a fingerprint sensor LSI to obtain high-quality fingerprint images suitable for identification. The scheme is based on novel evaluation indexes of fingerprint-image quality and adjustable analog-to-digital (A/D) conversion. The scheme adjusts dynamically an A/D conversion range of the fingerprint sensor LSI while evaluating the image quality during real-time fingerprint-sensing operation. The evaluation indexes pertain to the contrast and the ridgelines of a fingerprint image. The A/D conversion range is adjusted by changing quantization resolution and offset. We developed a fingerprint sensor LSI and a user authentication system to evaluate the adaptive fingerprint-sensing scheme. The scheme obtained a fingerprint image suitable for identification and the system achieved an accurate identification rate with 0.36% of the false rejection rate (FRR) at 0.075% of the false acceptance rate (FAR). This confirms that the scheme is very effective in achieving accurate identification.