A 5.4 kHz, 6th-order elliptic bandpass gm-C filter for portable biomedical applications is described. The circuit includes automatic on-chip center frequency tuning utilizing a 32 kHz system clock as a reference. The aim was to minimize filter area and power consumption. The design has been integrated in a 0.6 /spl mu/m CMOS process. Core area is 1.07 mm/sup 2/ of which the tuning circuitry constitutes 0.24 mm/sup 2/. Measured current consumption of the filter including tuning circuitry is 18 /spl mu/A with a 3 V supply voltage.