MAX291CSA+T

Overview

The MAX291CSA+T is an 8th-order, lowpass, switched-capacitor filter in the MAX291 series. It provides a maximally flat Butterworth response with a clock-tunable corner frequency range of 0.1Hz to 25kHz. The device operates on a single +4.75V to +11V supply or dual ±2.375V to ±5.5V supplies. It features an internal oscillator requiring only an external capacitor, or supports an external clock input. An uncommitted operational amplifier is included for post-filtering or anti-aliasing tasks.

Feature Summary

• Provides 8th-order lowpass filtering with a maximally flat Butterworth passband response.
• Enables corner frequency tuning from 0.1Hz to 25kHz via internal oscillator or external clock signals.
• Integrates an uncommitted operational amplifier for additional continuous-time filtering stages.

Applications

• Anti-aliasing filters preceding analog-to-digital converters
• Post-filtering stages following digital-to-analog converters
• Noise analysis and signal conditioning circuits

Procurement Notes

Verify the component designation against official Analog Devices documentation to confirm the specific package type and temperature rating. Ensure that the ordering suffix aligns with the required industrial specifications. Cross-reference the manufacturer's part number directly with authorized distributors to validate authenticity and current availability status.

Selection Notes

Select this component when a fixed 8th-order Butterworth response is required without external resistors. Verify that the application can accommodate the necessary clock frequency ratio relative to the desired cutoff point. Confirm that the power supply architecture matches the specified voltage ranges for optimal performance.

Part Context

This device belongs to the MAX291 family of switched-capacitor filters manufactured by Analog Devices / Maxim Integrated. The series includes variants such as the MAX292, MAX295, and MAX296, which offer different filter responses like Bessel or extended frequency ranges. The CSA suffix specifically denotes the 8-pin SO package configuration.

Replacement Considerations

Direct replacements within the same family include the MAX291ESA for extended temperature ranges. Other functional alternatives within the series are the MAX292, MAX295, and MAX296, depending on whether Bessel response or higher frequency limits are needed.

FAQ

How is the corner frequency determined?

The corner frequency is set by the clock frequency applied to the CLK pin, utilizing a 100:1 clock-to-corner-frequency ratio.

Can the internal oscillator be used?

Yes, an external capacitor connected between the CLK pin and ground sets the internal oscillator frequency.

What is the purpose of the OP OUT pin?

It connects to an uncommitted operational amplifier that can be configured for additional filtering or noise attenuation.