MAX271CWG+

Overview

The MAX271CWG+ is a digitally-programmed, dual second-order continuous-time lowpass filter housed in a 20-pin Wide SOIC package. It operates within a supply voltage range of ±2.375V to ±8V and draws 6.5mA typical quiescent current. The device provides two independent filter sections with programmable cutoff frequencies ranging from 1kHz to 25kHz via 7-bit digital inputs. It features a dynamic range exceeding 96dB and includes an integrated track-and-hold circuit. Shutdown mode reduces supply current to less than 15µA.

Feature Summary

• Continuous-time filtering architecture eliminates clock noise associated with switched-capacitor designs.
• Dual independently programmable second-order lowpass filter sections allow flexible system configuration.
• Integrated track-and-hold circuit enables direct sampling of filtered signals without external components.
• Low-power shutdown mode disconnects outputs and minimizes standby current consumption.

Applications

• Anti-aliasing filters for data acquisition systems
• Output smoothing for digital-to-analog converters
• Low-noise signal conditioning circuits

Procurement Notes

Verify the component is sourced from authorized distributors or Analog Devices directly. Confirm the suffix 'WG+' indicates the lead-free/RoHS-compliant 20-pin Wide SOIC package variant. Ensure the operating temperature range matches the 'C' designation (0°C to +70°C) for your specific application requirements.

Selection Notes

Select the MAX271CWG+ when a built-in track-and-hold function is required alongside dual filtering capabilities. Choose this part over the MAX270 if the uncommitted op amp is unnecessary and T/H functionality is preferred. Verify that the 1kHz to 25kHz cutoff frequency range aligns with the signal bandwidth needs.

Part Context

This component belongs to the MAX270/MAX271 family of digitally-programmed continuous-time filters. The MAX271 variant specifically integrates a track-and-hold amplifier, distinguishing it from the MAX270 which includes an uncommitted operational amplifier instead. Both share identical filter core characteristics and pinouts.

Replacement Considerations

The MAX270CWG+ serves as a functional substitute if the track-and-hold feature is not needed and an uncommitted op amp is desired instead. Other variants within the MAX270/MAX271 series offer different temperature ranges or packaging options but maintain electrical compatibility.

FAQ

How are the filter cutoff frequencies programmed?

Cutoff frequencies between 1kHz and 25kHz are set using 7-bit digital data inputs (D0–D6). This can be done via microprocessor control in FP mode or by hard-wiring pins in pin-strap mode.

What is the difference between the MAX270 and MAX271?

The MAX271 includes an internal track-and-hold circuit, whereas the MAX270 contains an uncommitted operational amplifier. Both devices feature dual second-order lowpass filters.

Can the filter sections be cascaded?

Yes, the two filter sections can be cascaded to achieve higher-order responses, such as a fourth-order rolloff, by connecting the output of one section to the input of the other.