MAX293:8th-Order, Lowpass, Elliptic, Switched-Capacitor Filters

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

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.

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
MAX293, MAX294, MAX297: Typical Operating Circuit
MAX293, MAX294, MAX297: Typical Operating Circuit
Applications/Uses
  • Anti-Aliasing
  • DAC Post-Filtering
  • Data-Acquisition Systems
  • Voice/Data Signal Filtering
DataSheet
titleDownload file
MAX293-MAX297 Data SheetMAX293-MAX297.pdf
Parametrics
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
MAX29318Switched 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
MAX29425CDIP(N)/8
PDIP(N)/8
SOIC(N)/8
SOIC(W)/16
$5.17 @1k
MAX29750CDIP(N)/8
PDIP(N)/8
SOIC(N)/8
SOIC(W)/16
$4.68 @1k
Quality and Environmental Data
Related Products
  • MAX7408:5th Order, Lowpass, Elliptic, Switched-Capacitor Filters
  • MAX7407:8th-Order, Lowpass, Elliptic, Switched-Capacitor Filters
  • MAX7400:8th-Order, Lowpass, Elliptic, Switched-Capacitor Filters
  • MAX7403:8th-Order, Lowpass, Elliptic, Switched-Capacitor Filters
  • MAX7404:8th-Order, Lowpass, Elliptic, Switched-Capacitor Filters
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX293C/DLast Time BuyMAX293ESA+DICE SALES,;NA pin;DICE S;0°C to +70°CSee data sheet
MAX293CPANo Longer AvailableMAX293CPA+PDIP(N),;8 pin;79.7 mm²0°C to +70°CNo
MAX293CPA+ActivePDIP(N),;8 pin;79.7 mm²0°C to +70°CLead Free
MAX293CSANo Longer AvailableMAX293CSA+SOIC(N),;8 pin;30.9 mm²0°C to +70°CNo
MAX293CSA+ActiveSOIC(N),;8 pin;30.9 mm²0°C to +70°CLead Free
MAX293CSA+TActiveSOIC(N),;8 pin;30.9 mm²0°C to +70°CLead Free
MAX293CSA-TNo Longer AvailableMAX293CSA+TN.SO;8 pin0°C to +70°CSee data sheet
MAX293CWENo Longer AvailableMAX293CWE+SOIC(W),;16 pin;111.8 mm²0°C to +70°CNo
MAX293CWE+ActiveSOIC(W),;16 pin;111.8 mm²0°C to +70°CLead Free
MAX293CWE+TActiveSOIC(W),;16 pin;111.8 mm²0°C to +70°CLead Free
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX293CWE-TNo Longer AvailableMAX293CWE+TW.SO;16 pin0°C to +70°CSee data sheet
MAX293EPANo Longer AvailableMAX293EPA+PDIP(N),;8 pin;79.7 mm²-40°C to +85°CNo
MAX293EPA+ActivePDIP(N),;8 pin;79.7 mm²-40°C to +85°CLead Free
MAX293ESANo Longer AvailableMAX293ESA+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
MAX293ESA+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX293ESA+TActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX293ESA-TNo Longer AvailableMAX293ESA+TN.SO;8 pin-40°C to +85°CSee data sheet
MAX293EWENo Longer AvailableMAX293EWE+SOIC(W),;16 pin;111.8 mm²-40°C to +85°CNo
MAX293EWE+ActiveSOIC(W),;16 pin;111.8 mm²-40°C to +85°CLead Free
MAX293EWE+TActiveSOIC(W),;16 pin;111.8 mm²-40°C to +85°CLead Free
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX293EWE-TNo Longer AvailableMAX293EWE+TW.SO;16 pin-40°C to +85°CSee data sheet
MAX293MJAActiveCDIP(N),;8 pin;82.6 mm²-55°C to +125°CNo
MAX293-MAX297.pdf MAX297
Telephone Tone Generator Requires No Trimming MAX293
MAX293.pdf MAX293
MAX293-MAX297.pdf MAX297