Dual Universal Switched-Capacitor Filters

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The MAX7490/MAX7491 consist of two identical low-power, low-voltage, wide dynamic range, rail-to-rail, 2nd-order switched-capacitor building blocks. Each of the two filter sections, together with two to four external resistors, can generate all standard 2nd-order functions: bandpass, lowpass, highpass, and notch (band reject). Three of these functions are simultaneously available. Fourth-order filters can be obtained by cascading the two 2nd-order filter sections. Similarly, higher order filters can easily be created by cascading multiple MAX7490/MAX7491s.

Two clocking options are available: self-clocking (through the use of an external capacitor) or external clocking for tighter cutoff frequency control. The clock-to-center frequency ratio is 100:1. Sampling is done at twice the clock frequency, further separating the cutoff frequency and Nyquist frequency.

The MAX7490/MAX7491 have an internal rail splitter that establishes a precise common voltage needed for single-supply operation. The MAX7490 operates from a single +5V supply and the MAX7491 operates from a single +3V supply. Both devices feature a low-power shutdown mode and come in a 16-pin QSOP package.
MAX7490, MAX7491: Typical Application Circuit MAX7490, MAX7491: Typical Application Circuit Enlarge+

Key Features

  • Dual 2nd-Order Filter in a 16-Pin QSOP Package
  • High Accuracy
    • Q Accuracy: ±0.2%
    • Clock-to-Center Frequency Error: ±0.2%
  • Rail-to-Rail Input and Output Operation
  • Single-Supply Operation: +5V (MAX7490) or +3V (MAX7491)
  • Internal or External Clock
  • Highpass, Lowpass, Bandpass, and Notch Filters
  • Clock-to-Center Frequency Ratio of 100:1
  • Internal Sampling-to-Center Frequency Ratio of 200:1
  • Center Frequency up to 40kHz
  • Easily Cascaded for Multipole Filters
  • Low-Power Shutdown: < 1µA Supply Current


  • Adaptive Filters
  • ADC Anti-Aliasing
  • Multipole Filters
  • Phase-Locked Loops (PLLs)
  • Post-DAC Filtering
  • Set-Top Boxes
  • Tunable Active Filters

See parametric specs for Active Filters (47)

Part NumberFilter SectionsOrder Per Filter SectionFilter ClassFilter TypeFilter CharacteristicProgram MethodLowest Cutoff
Highest Cutoff
Oper. Temp.
maxminSee Notes
MAX7490 22Switched CapUniversalProgrammableClock1405
-40 to +85
0 to +70
$4.15 @1k
MAX7491 3
$4.60 @1k

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
Request Reliability Report for: MAX7490 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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