A high-performance micropower switched-capacitor filter

—MOS technology scaling requires the use of lower supply
voltages. Analog circuits operating from a low supply and achieving a
sufficiently farge dynamic range must be designed if analogidigital interfaces
are to be implemented in scaled technologies. This paper describes a
high-performance fifth-order low-pass switched-capacitor filter operating
from a single 5-V supply. The filter uses a fully differential topology
combined with input-to-output class A B amplifier design, dynamic biasing,
and switched-capacitor common-mode feedback (CMFB). An experimental
prototype fabricated in a 5- p m CMOS technology requires orlly 350 pW of
power to meet the PCM channel filter requirements. Typical measured
results are a dynamic range of 92 dB, a supply rejection (PSRR) of 40 dB
over the entire Nyquist range, and a total harmonic distortion (THD) of
– 73 dB for a 2-V rms dlfferentiaf output signal. The chip active area is
about 3900 milz.