MAX291CSA+

Overview

The MAX291CSA+ is an 8th-order, lowpass, switched-capacitor filter in the MAX291 series. It provides a Butterworth response with a corner frequency range of 0.1Hz to 25kHz. The device operates on single +4.75V to +11V or dual ±2.375V to ±5.5V supplies. It features a clock-to-corner-frequency ratio of 100:1 and includes an uncommitted operational amplifier. The component is housed in an 8-pin SO package and supports operation from 0°C to +70°C.

Feature Summary

• Provides maximally flat passband response characteristic of Butterworth filters
• Enables corner frequency tuning via internal oscillator or external clock signals
• Integrates an uncommitted operational amplifier for post-filtering or anti-aliasing applications

Applications

• ADC Anti-Aliasing Filter
• DAC Post-Filtering
• Noise Analysis
• 50Hz/60Hz Line-Noise Filtering

Procurement Notes

Verify the specific suffix CSA against official documentation to confirm the 8-pin Small Outline package and commercial temperature range. Confirm RoHS compliance status through authorized distributors or manufacturer channels before procurement. Ensure supply voltage requirements match the design constraints.

Selection Notes

Select the MAX291CSA+ when a maximally flat Butterworth response is required for signal conditioning. Choose this part over Bessel variants if phase linearity is less critical than stopband attenuation. Verify that the application requires a corner frequency within the 0.1Hz to 25kHz range supported by the 100:1 clock ratio.

Part Context

The MAX291CSA+ belongs to the MAX291/MAX292/MAX295/MAX296 family of 8th-order lowpass switched-capacitor filters. This series allows designers to set filter characteristics primarily through clock frequency selection rather than external passive components. The MAX291 specifically implements the Butterworth response profile within this lineup.

Replacement Considerations

The MAX291C/D serves as a pin-compatible alternative in a 16-pin Wide SO package. For extended temperature ranges, the MAX291ESA covers -40°C to +85°C in an 8-pin SO package. Verify package dimensions and electrical specifications before substitution.

FAQ

How is the corner frequency determined?

The corner frequency is controlled by the clock frequency applied to the CLK pin, maintaining a fixed 100:1 ratio between the clock and the corner frequency.

Can the device operate with a single power supply?

Yes, the MAX291CSA+ can operate with a single supply ranging from +4.75V to +11V, or dual supplies from ±2.375V to ±5.5V.

What is the function of the OP OUT pin?

The OP OUT pin connects to an uncommitted operational amplifier provided within the chip, which can be configured for continuous-time filtering or clock-noise attenuation.