General Description

The MAX7401/MAX7405 8th-order, lowpass, Bessel, switched-capacitor filters (SCFs) operate from a single +5V (MAX7401) or +3V (MAX7405) supply. These devices draw only 2mA of supply current and allow corner frequencies from 1Hz to 5kHz, 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 on these devices: 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 MAX7401/MAX7405 Bessel filters provide low over shoot and fast settling. Their fixed response simplifies the design task to selecting a clock frequency.

Features

♦ 8th-Order, Lowpass Bessel Filters

♦ Low Noise and Distortion: -82dB THD + Noise

♦ Clock-Tunable Corner Frequency (1Hz to 5kHz)

♦ 100:1 Clock-to-Corner Ratio

♦ Single-Supply Operation

   +5V (MAX7401)

   +3V (MAX7405)

♦ Low Power

   2mA (Operating Mode)

   0.2µA (Shutdown Mode)

♦ Available in 8-Pin SO/DIP Packages

♦ Low Output Offset: ±5mV

Applications

   ADC Anti-Aliasing

   CT2 Base Stations

   Post-DAC Filtering

   Speech Processing

   Air-Bag Electronics