MAX271EWG+

Overview

The MAX271EWG+ is a digitally-programmed, dual second-order continuous-time lowpass filter in a 20-pin Wide SO package. It operates within a supply voltage range of ±2.375V to ±8V and supports cutoff frequencies from 1kHz to 25kHz via 7-bit digital control. The device features two independent filter sections with a typical dynamic range of 96dB and includes an integrated track-and-hold circuit. It offers a low-power shutdown mode consuming less than 15µA and is rated for operation between -40°C and +85°C.

Feature Summary

• Dual second-order Sallen-Key continuous-time lowpass filter sections
• Integrated track-and-hold circuit for signal sampling
• Digitally programmable cutoff frequencies from 1kHz to 25kHz
• Low-power shutdown mode with minimal quiescent current

Applications

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

Procurement Notes

Verify the component authenticity by checking the manufacturer markings against official datasheet specifications. Confirm the package type matches the required footprint and ensure the temperature grade aligns with system operational requirements. Cross-reference the ordering suffix to confirm lead-free compliance status as documented by the manufacturer.

Selection Notes

Select this component when a dual-channel continuous-time filter with integrated sampling is required. Ensure the application supports the specified bipolar or unipolar supply voltages. Verify that the digital interface logic levels are compatible with the system microcontroller or control circuitry for proper frequency programming.

Part Context

This part belongs to the MAX270/MAX271 family of analog filters. The MAX271 variant specifically integrates a track-and-hold function, distinguishing it from the MAX270 which provides an uncommitted operational amplifier instead. Both share identical filter core characteristics and digital programming interfaces.

Replacement Considerations

The MAX270EWG+ serves as a functional substitute if the track-and-hold feature is not required, offering an uncommitted op amp instead. Other variants within the MAX270/MAX271 series may be considered based on specific temperature ranges or package configurations.

FAQ

How is the filter cutoff frequency determined?

The cutoff frequency is set by applying a 7-bit digital code (D0-D6) to the data pins. This code selects one of 128 predefined frequencies ranging from 1kHz to 25kHz.

What is the purpose of the MODE pin on the MAX271?

The MODE pin selects the operating mode. Connecting it to GND or V- enables microprocessor control mode, while connecting it to V+ enables pin-strap mode for direct hardware configuration without timing requirements.

Can the two filter sections be cascaded?

Yes, the two filter sections can be cascaded to achieve higher-order roll-off characteristics, such as a 4th-order response with approximately 80dB/decade attenuation.