A CD analog front-end in BiCMOS technology

A BiCMOS analog front-end to be used in a complete two-chip set with a digital signal processor for Compact Disk (CD) is presented. The proposed device exchanges data with the digital counterpart by means of a I2C-like bus serial interface. Four input signals (current or voltage) are preamplified with flat group-delay and digitized with 6-bit (for servo path) and 8-bit (for RF path) accuracy. This accuracy is achieved without using an equalizer in the signal path. The system is designed to process CD signal with speed up to 4x (i.e. 3.2MHz bandwidth). The device is realized in a 0.7µm BiCMOS technology using 21.5mm²chip area.