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Dual Universal Switched-Capacitor Filters

Product Details

Key Features

Applications/Uses

Parametric specs for Active Filters
Filter Type Universal
Filter Sections 2
Order Per Filter Section 2
Highest Cutoff (kHz) (min) 40
Lowest Cutoff (Hz) (max) 1
Filter Class Switched Cap
Filter Characteristic Programmable
Program Method Clock
Oper. Temp. (°C) -40 to +85
0 to +70
Package/Pins QSOP/16
Budgetary
Price (See Notes)
4.6
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Simplified Block Diagram

Technical Docs

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Parameters

Parametric specs for Active Filters
Filter Type Universal
Filter Sections 2
Order Per Filter Section 2
Highest Cutoff (kHz) (min) 40
Lowest Cutoff (Hz) (max) 1
Filter Class Switched Cap
Filter Characteristic Programmable
Program Method Clock
Oper. Temp. (°C) -40 to +85
0 to +70
Package/Pins QSOP/16
Budgetary
Price (See Notes)
4.6

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

Applications/Uses

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

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 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.

Simplified Block Diagram

MAX7490, MAX7491: Typical Application Circuit MAX7490, MAX7491: Typical Application Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .