MAX294:8th-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
MAX294C/DNo Longer AvailableMAX294ESA+DICE SALES,;NA pin;DICE;0°C to +70°CSee data sheet
MAX294CPANo Longer AvailableMAX294CPA+PDIP(N),;8 pin;79.7 mm²0°C to +70°CNo
MAX294CPA+ActivePDIP(N),;8 pin;79.7 mm²0°C to +70°CLead Free
MAX294CSANo Longer AvailableMAX294CSA+SOIC(N),;8 pin;30.9 mm²0°C to +70°CNo
MAX294CSA+ActiveSOIC(N),;8 pin;30.9 mm²0°C to +70°CLead Free
MAX294CSA+TActiveN.SO;8 pin0°C to +70°CSee data sheet
MAX294CSA-TNo Longer AvailableMAX294CSA+TN.SO;8 pin0°C to +70°CSee data sheet
MAX294CWENo Longer AvailableMAX294CWE+SOIC(W),;16 pin;111.8 mm²0°C to +70°CNo
MAX294CWE+ActiveSOIC(W),;16 pin;111.8 mm²0°C to +70°CLead Free
MAX294CWE+TActiveW.SO;16 pin0°C to +70°CSee data sheet
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX294CWE-TNo Longer AvailableMAX294CWE+TW.SO;16 pin0°C to +70°CSee data sheet
MAX294EPANo Longer AvailableMAX294EPA+PDIP(N),;8 pin;79.7 mm²-40°C to +85°CNo
MAX294EPA+ActivePDIP(N),;8 pin;79.7 mm²-40°C to +85°CLead Free
MAX294ESANo Longer AvailableMAX294ESA+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
MAX294ESA+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX294ESA+TActiveN.SO;8 pin-40°C to +85°CSee data sheet
MAX294ESA-TNo Longer AvailableMAX294ESA+TN.SO;8 pin-40°C to +85°CSee data sheet
MAX294EWENo Longer AvailableMAX294EWE+SOIC(W),;16 pin;111.8 mm²-40°C to +85°CNo
MAX294EWE+ActiveSOIC(W),;16 pin;111.8 mm²-40°C to +85°CLead Free
MAX294EWE+TActiveSOIC(W),;16 pin;111.8 mm²-40°C to +85°CLead Free
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX294EWE-TNo Longer AvailableMAX294EWE+TW.SO;16 pin-40°C to +85°CSee data sheet
MAX294MJANo Longer AvailableCDIP(N),;8 pin;82.6 mm²-55°C to +125°CNo
MAX293-MAX297.pdf MAX297
MAX294.pdf MAX294
MAX293-MAX297.pdf MAX297