This document introduces the LTC6601-1/-2 and LTC6605-7/-10/-14, 3 precision matched baseband filter ICs that provide precision filtering performance in the 1.25MHz to 20MHz frequency range.
In digital communication systems, baseband signals require band-limiting. While digital signal processing handles much of this task, analog filtering is essential for reducing DAC imaging, filtering RF demodulator noise, and minimizing ADC aliasing. Discrete analog filters using op amps, resistors, and capacitors are sensitive to PCB parasitics and component tolerances in the 1.25MHz to 20MHz range typically used in 3G systems.
Lowpass filters can be produced with cutoff frequencies ranging from 5MHz to 27MHz.
The maximum gain matching error is +0.35dB and the phase matching error is +1.2°.
Power is set by a three-state BIAS pin allowing shutdown (Ig = 350A), medium power (Is = 16mA), or full power (Ig = 33mA).