The Texas Instruments TLC04CD is a 4th-order Butterworth low-pass switched-capacitor filter IC with a cutoff frequency of 30kHz. It is available in an 8-SOIC surface mount package.
The Texas Instruments TLC14ID is a Butterworth fourth-order low-pass switched-capacitor filter. It operates from 5V to 12V and features a cutoff frequency of 30kHz.
The MAX291ESA+T is an 8th-order, lowpass, switched-capacitor filter from Analog Devices / Maxim Integrated. It features a clock-tunable corner frequency range up to 25kHz.
