A 100 MHz Gm-C bandpass filter chip design for wireless application

A sixth-order Butterworth bandpass filter using a leap-frog G_m-C structure for wireless applications is proposed. The filter is targeted for an intermediate frequency (IF) receiver, which has a center frequency of 100 MHz and a passband of 20 MHz. Fully differential Nauta's transconductors are used in this design, allowing the circuit to work over a large frequency range. The single-to-differential converter before the filter is designed in order to provide differential output for filter usage. The proposed bandpass filter including converter has been fabricated in TSMC 0.35 urn CMOS process with 3.3 V supply voltage. Measured results show that the proposed G_m-C bandpass filter achieves a center frequency of 94.45 MHz and a passband of 25 MHz. The chip area including pads is only 0.475 mm² and the power dissipation is 42.25 mW.