MAX7401CSA

Overview

The MAX7401CSA is an 8th-order, lowpass, Bessel switched-capacitor filter operating from a single +5V supply. It provides a clock-tunable corner frequency ranging from 1Hz to 5kHz with a fixed 100:1 clock-to-corner ratio. The device draws 2mA in operating mode and reduces to 0.2µA in shutdown mode. It features low noise and distortion (-82dB THD+N), low output offset (±5mV), and offers self-clocking via an external capacitor or external clocking for precise control. Packaged in an 8-pin SOIC, it supports an operating temperature range of 0°C to +70°C.

Feature Summary

• Provides 8th-order lowpass Bessel filtering characteristics with fast settling times and minimal overshoot.
• Supports flexible clocking options including internal oscillator tuning via external capacitor or external clock input.
• Includes a low-power shutdown mode that significantly reduces supply current consumption.

Applications

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

Procurement Notes

Verify the specific suffix CSA corresponds to the 8-pin SO package and 0°C to +70°C temperature range. Confirm the manufacturer designation matches Analog Devices Inc./Maxim Integrated as per the provided datasheet documentation. Ensure the component meets RoHS compliance requirements if applicable to the target assembly process.

Selection Notes

Select this component when an 8th-order Bessel response is required for applications needing fast settling times, such as multiplexed ADC inputs. Choose between internal or external clocking based on the need for corner frequency precision versus design simplicity. Ensure the system operates within the specified +5V single-supply constraint and temperature limits.

Part Context

This part belongs to the MAX7401/MAX7405 family of switched-capacitor filters. The MAX7401 variant is designed for +5V operation, while the MAX7405 operates at +3V. Both share identical electrical characteristics and pinouts, differing primarily in supply voltage requirements. The CS suffix indicates commercial temperature range availability.

Replacement Considerations

The MAX7405 serves as a direct functional substitute if the application requires +3V operation instead of +5V. Other parts in the MAX29x series offer similar switched-capacitor functionality but may require different supply configurations or have varying order specifications.

FAQ

How is the corner frequency determined?

The corner frequency is set by the clock frequency using a fixed 100:1 ratio (fC = fCLK / 100). It can be controlled via an external clock or an internal oscillator defined by a capacitor connected to the CLK pin.

What is the function of the SHDN pin?

The SHDN pin controls the shutdown mode. Driving it low activates shutdown, reducing supply current to 0.2µA and placing the output in a high-impedance state. Driving it high enables normal operation.

Can the output offset be adjusted?

Yes, the OS pin allows for DC output level adjustment. Connecting OS to COM disables adjustment, while applying an external bias voltage to OS shifts the output DC level.