MAX7401CSA+T

Overview

The MAX7401CSA+T is an 8th-order, lowpass, Bessel switched-capacitor filter from Analog Devices Inc./Maxim Integrated. It operates on a single +5V supply and features a clock-to-corner frequency ratio of 100:1, allowing corner frequencies between 0.001kHz and 5kHz. The device draws 2mA in operating mode and 0.2µA in shutdown mode. Key electrical parameters include a typical Total Harmonic Distortion plus Noise (THD+N) of -82dB, an output offset voltage of ±5mV, and a maximum capacitive load drive of 500pF at the output.

Feature Summary

• Provides 8th-order lowpass Bessel filtering with fast settling times suitable for multiplexed analog inputs.
• Supports both self-clocking via external capacitor and external clocking for precise corner frequency control.
• Includes a dedicated shutdown pin to reduce power consumption significantly when inactive.
• Features an offset adjust input for DC level shifting or output offset calibration.

Applications

• ADC anti-aliasing
• Post-DAC filtering
• Speech processing

Procurement Notes

Verify the component authenticity by checking the manufacturer's marking against official datasheet specifications. Confirm the package type matches the required PCB footprint. Ensure the temperature range meets the operational environment requirements before finalizing procurement decisions.

Selection Notes

Select this component for applications requiring high-order filtering with minimal overshoot. Consider the MAX7405 if a +3V supply is preferred. Ensure the clock source can provide the necessary frequency range to achieve the desired cutoff frequency within the 100:1 ratio constraint.

Part Context

This part belongs to the MAX7401/MAX7405 family of switched-capacitor filters. It shares architectural similarities with other Maxim integrated filters but is distinct in its specific order, response type, and supply voltage requirements compared to broader product lines.

Replacement Considerations

Direct replacements include the MAX7401ESA for the same electrical performance in an SO package. Verify compatibility regarding pinout and thermal characteristics when substituting with other SCF devices.

FAQ

How is the internal oscillator frequency determined?

The internal oscillator frequency is set by connecting a capacitor (COSC) between the CLK pin and ground. For the MAX7401, the frequency is approximately 38,000 divided by the COSC value in picofarads.

What is the function of the OS pin?

The OS pin allows for adjustment of the DC output level. It can be connected to COM for no offset adjustment or biased externally to shift the output DC voltage.

Can the MAX7401 operate with dual supplies?

Yes, while designed for single-supply operation (+5V), it can operate with dual supplies (e.g., ±2.5V) by connecting the COM pin to system ground.