Description

The MAX7490/MAX7491 consist of two identical low-power,low-voltage, wide dynamic range, rail-to-rail,2nd-order switched-capacitor building blocks. Each ofthe two filter sections, together with two to four externalresistors, can generate all standard 2nd-order functions:bandpass, lowpass, highpass, and notch (bandreject). Three of these functions are simultaneouslyavailable. Fourth-order filters can be obtained by cascadingthe two 2nd-order filter sections. Similarly, higherorder filters can easily be created by cascadingmultiple MAX7490/MAX7491s.Two clocking options are available: self-clocking(through the use of an external capacitor) or externalclocking for tighter cutoff frequency control. The clock-to-center frequency ratio is 100:1. Sampling is done attwice the clock frequency, further separating the cutofffrequency and Nyquist frequency.The MAX7490/MAX7491 have an internal rail splitterthat establishes a precise common voltage needed forsingle-supply operation. The MAX7490 operates from asingle +5V supply and the MAX7491 operates from asingle +3V supply. Both devices feature a low-powershutdown mode and come in a 16-pin QSOP package.ApplicationsAdaptive FiltersADC Anti-AliasingMultipole FiltersPhase-Locked Loops (PLLs)Post-DAC FilteringSet-Top BoxesTunable Active Filters