MAX293

8th-Order, Lowpass, Elliptic, Switched-Capacitor Filters

Also See MAX7400/3/4/7 for Lowest-Power Applications


Please check latest availability status for a specific part variant.

Description

The MAX293/MAX294/MAX297 are easy-to-use, 8th-order, lowpass, elliptic, switched-capacitor filters that can be set up with corner frequencies from 0.1Hz to 25kHz (MAX293/MAX294) or from 0.1Hz to 50kHz (MAX297).

The MAX293/MAX297's 1.5 transition ratio provides sharp rolloff and -80dB of stopband rejection. The MAX294's 1.2 transition ratio provides the steepest rolloff and -58dB of stopband rejection. All three 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 op amp (noninverting input grounded) is provided for building a continuous-time lowpass filter for post-filtering or anti-aliasing. Steep rolloff and high order make these filters ideal for anti-aliasing applications that require maximum bandwidth, and for communication applications that require filtering signals in close proximity within the frequency domain.

The MAX293/MAX294/MAX297 are available in 8-pin DIP and 16-pin wide SO packages, delivering aggressive performance from a tiny area.
MAX293, MAX294, MAX297: Typical Operating Circuit MAX293, MAX294, MAX297: Typical Operating Circuit Enlarge+

Key Features

  • 8th-Order Lowpass Elliptic Filters
  • Clock-Tunable Corner-Frequency Range:
    • 0.1Hz to 25kHz (MAX293/MAX294)
    • 0.1Hz to 50kHz (MAX297)
  • No External Resistors or Capacitors Required
  • Internal or External Clock
  • Clock to Corner Frequency Ratio
    • 100:1 (MAX293/MAX294)
    • 50:1 (MAX297)
  • Operate with a Single +5V Supply or Dual ±5V Supplies
  • Uncommitted Op Amp for Anti-Aliasing or Clock-Noise Filtering
  • 8-Pin DIP and 16-Pin Wide SO Packages

Applications/Uses

  • Anti-Aliasing
  • DAC Post-Filtering
  • Data-Acquisition Systems
  • Voice/Data Signal Filtering
Part NumberFilter SectionsOrder Per Filter SectionFilter ClassFilter TypeFilter CharacteristicProgram MethodLowest Cutoff
(Hz)
Highest Cutoff
(kHz)
VSUPPLY (Dual)
(±V)
VSUPPLY
(V)
Oper. Temp.
(°C)
Package/PinsBudgetary
Price
maxminDualSee Notes
MAX293 18Switched CapLowpassEllipticClock0.12555
-55 to +125
-40 to +85
0 to +70
CDIP(N)/8
PDIP(N)/8
SOIC(N)/8
SOIC(W)/16
$4.73 @1k
MAX294 25
CDIP(N)/8
PDIP(N)/8
SOIC(N)/8
SOIC(W)/16
$6.01 @1k
MAX297 50
CDIP(N)/8
PDIP(N)/8
SOIC(N)/8
SOIC(W)/16
$4.68 @1k
See All Active Filters (50)
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.

Technical Documents

App Note 1904 Telephone Tone Generator Requires No Trimming

Quality and Environmental Data

Product Reliability Reports: MAX293.pdf 
Lead-Free Package Tin (Sn) Whisker Reports
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

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.

Quality Management System >
Environmental Management System >

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