MAX291 Datasheet

• 8th-Order Lowpass Filters:
  • Butterworth (MAX291)
• Clock-Tunable Corner-Frequency Range:
  • 0.1Hz to 25kHz (MAX291)
• No External Resistors or Capacitors Required
• Internal or External Clock
• Clock to Corner Frequency Ratio:
  • 100:1 (MAX291)
• Low Noise: -70dB THD + Noise (Typ)
• Operate with a Single +5V Supply or Dual ±5V Supplies
• Uncommitted Op Amp for Anti-Aliasing or Clock-Noise Filtering
• 8-Pin DIP and SO Packages

• 50Hz/60Hz Line-Noise Filtering
• ADC Anti-Aliasing Filter
• DAC Post-Filtering
• Noise Analysis

The MAX291 are easy-to-use, 8th-order, lowpass, switched-capacitor filters that can be set up with corner frequencies from 0.1Hz to 25kHz (MAX291).

The MAX291 Butterworth filters provide maximally flat passband response. All four filters have fixed responses, so the design task is limited to selecting the clock frequency that controls the filter's corner frequency.

An external capacitor is used to generate a clock using the internal oscillator, or an external clock signal can be used. An uncommitted operational amplifier (noninverting input grounded) is provided for building a continuous time lowpass filter for post-filtering or anti-aliasing.

Produced in an 8-pin DIP/SO and a 16-pin wide SO package, and requiring a minimum of external components, the MAX291 series delivers very aggressive performance from a tiny area.