A 1.2 V BiCMOS class AB log-domain filter

摘要: Companding improves dynamic range in situations with restricted signal swing, such as low-voltage circuits, without the need to reduce noise at cost of increased power dissipation. The log-domain filter principle achieves instantaneous companding by taking advantage exponential device characteristics. Thanks high compression ratio, voltage swing and frequency tuning become almost independent supply voltage, which can be reduced minimum required for proper operation. combination class AB operation permits processing signals much larger than bias level hence increases substantially. Class filters are suited low applications moderate signal-to-noise ratio (SNR) linearity requirements. authors present a 3/sup rd/-order Chebyshev is based on an integrator implemented 1 /spl mu/m BiCMOS process. tuned over more 3 decades cut-off frequencies ranging from 10 kHz 15 MHz voltages between 0.9 V 2 V. For 1.2 supply, up about achieved.