MAX7409EPA+

Overview

The MAX7409EPA+ is a fifth-order, lowpass switched-capacitor filter with a Bessel response. It operates from a single +5V supply and features a clock-tunable corner frequency ranging from 1Hz to 15kHz. The device draws 1.2mA in operating mode and reduces to 0.2µA in shutdown mode. It offers an internal oscillator or external clock input for precise control, with a fixed 100:1 clock-to-corner ratio. The output offset voltage is typically ±4mV. This component is housed in an 8-pin Plastic DIP package and supports an industrial temperature range of -40°C to +85°C.

Feature Summary

• Provides a fifth-order lowpass Bessel filter response characterized by low overshoot and fast settling times.
• Supports both self-clocking via an external capacitor and external clocking for tighter corner-frequency control.
• Includes a dedicated shutdown pin that significantly reduces power consumption when the device is inactive.
• Features an offset adjust pin allowing for DC output level adjustment relative to the common-mode input.

Applications

• ADC anti-aliasing
• DAC postfiltering
• Speech processing

Procurement Notes

Verify the specific suffix 'EPA+' corresponds to the required 8-pin PDIP package and the -40°C to +85°C temperature grade. Confirm RoHS compliance status through official manufacturer documentation before procurement. Ensure the ordering part number matches the exact electrical characteristics and package style required for the design.

Selection Notes

Select this component when a Bessel response is required for applications needing minimal overshoot and fast settling, such as multiplexed signal paths. Choose between internal oscillator or external clock based on the need for corner frequency stability versus design simplicity. Ensure the system supply voltage aligns with the +5V requirement for the MAX7409 series.

Part Context

The MAX7409 belongs to a family of fifth-order lowpass switched-capacitor filters that includes the MAX7410, MAX7413, and MAX7414. While the MAX7409 provides a Bessel response, the MAX7410 offers a Butterworth response. The MAX7413 and MAX7414 variants operate from a +3V supply, whereas the MAX7409 is designed for +5V operation.

Replacement Considerations

The MAX7410EPA+ serves as a direct functional substitute if a Butterworth response is acceptable instead of Bessel. The MAX7413EPA+ and MAX7414EPA+ are compatible regarding package and pinout but require a +3V supply instead of +5V.

FAQ

How is the corner frequency determined?

The corner frequency is set by the clock frequency divided by 100. It can be driven by an external clock or an internal oscillator generated by a capacitor connected to the CLK pin.

What is the function of the OS pin?

The Offset Adjust (OS) pin allows for the adjustment of the DC output level. It should be connected to COM if no offset adjustment is needed, or to an external bias voltage for DC level shifting.

How does the shutdown mode affect the output?

Driving the SHDN pin low activates shutdown mode, reducing supply current to 0.2µA and placing the filter output in a high-impedance state.