5th-Order, Lowpass, Switched-Capacitor Filters

The MAX7418–MAX7425 5th-order, low-pass, switched-capacitor filters (SCFs) operate from a single +5V (MAX7418–MAX7421) or +3V (MAX7422–MAX7425) supply. These devices draw only 3mA of supply current and allow corner frequencies from 1Hz to 45kHz, making them ideal for low-power post-DAC filtering and anti-aliasing applications. They feature a shutdown mode that reduces supply current to 0.2µA.

Two clocking options are available: self-clocking (through the use of an external capacitor), or external clocking for tighter corner-frequency control. An offset adjust pin allows for adjustment of the DC output level.

The MAX7418/MAX7422 deliver 53dB of stopband rejection and a sharp rolloff with a 1.6 transition ratio. The MAX7421/MAX7425 achieve a sharper rolloff with a 1.25 transition ratio while still providing 37dB of stopband rejection. The MAX7419/MAX7423 Bessel filters provide low overshoot and fast settling, and the MAX7420/MAX7424 Butterworth filters provide a maximally flat passband response. Their fixed response simplifies the design task of selecting a clock frequency.

APPLICATIONS

* ADC Anti-Aliasing

* CT2 Base Stations

* DAC Post-Filtering

* Speech Processing

* 5th-Order, Lowpass Filters

* Elliptic Response (MAX7418/MAX7421/MAX7422/MAX7425)

* Bessel Response (MAX7419/MAX7423)

* Butterworth Response (MAX7420/MAX7424)

* Clock-Turnable Corner Frequency (1Hz to 45kHz)

* Single-Supply Operation

* +5V (MAX7418–MAX7421)

* +3V (MAX7422–MAX7425)

* Low Power

* 3mA (Operating Mode)

* 0.2µA (Shutdown Mode)

* Available in 8-Pin µMAX® Package

* Low Output Offset: ±4mV