MAX291CSA

Overview

The MAX291CSA is an 8th-order, lowpass, switched-capacitor filter with a Butterworth response. It operates within a corner frequency range of 0.1Hz to 25kHz and maintains a clock-to-corner-frequency ratio of 100:1. The device supports single +5V or dual ±5V supplies (4.75V to 11V). It features an internal oscillator requiring only an external capacitor, or accepts an external clock up to 2.5MHz. An uncommitted op amp is included for anti-aliasing or noise filtering. The component is housed in an 8-pin SO package and functions within a temperature range of 0°C to +70°C.

Feature Summary

• Provides maximally flat passband response characteristic of Butterworth filters
• Eliminates the need for external resistors or capacitors for core filter operation
• Includes an uncommitted operational amplifier for additional signal conditioning

Applications

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

Procurement Notes

Verify the specific suffix CSA against official documentation to confirm the 8-pin SO package and commercial temperature range. Confirm RoHS compliance status through current manufacturer datasheets as ordering suffixes may indicate environmental variations. Ensure compatibility with existing board layouts regarding the SO footprint dimensions.

Selection Notes

Select this component when a fixed 8th-order Butterworth response is required without external tuning components. Verify that the application can accommodate the necessary clock frequency, which must be exactly 100 times the desired corner frequency. Consider the uncommitted op amp if additional continuous-time filtering stages are needed on the same chip.

Part Context

This part belongs to the MAX291/MAX292/MAX295/MAX296 family of switched-capacitor filters. While the MAX291 offers a Butterworth response, the MAX292 provides a Bessel response. The MAX295 and MAX296 variants extend the maximum corner frequency capability to 50kHz with a different clock ratio. All share similar pinouts and operational principles.

Replacement Considerations

MAX292CSA provides a Bessel response instead of Butterworth. MAX295CSA supports higher corner frequencies up to 50kHz. MAX291ESA covers the extended industrial temperature range of -40°C to +85°C.