MAX7421EUA+T

Overview

The MAX7421EUA+T is a fifth-order, low-pass, elliptic switched-capacitor filter (SCF) from the MAX7418–MAX7425 series. It operates from a single +5V supply and features an elliptic response with a transition ratio of 1.25. The corner frequency is clock-tunable from 1Hz to 30kHz using a 100:1 clock-to-corner ratio. Key electrical parameters include a typical supply current of 3mA in operating mode and 0.2μA in shutdown mode. The device offers a low output offset voltage of ±4mV and supports external clocking for precise control.

Feature Summary

• Elliptic low-pass filter response with a sharp rolloff characteristic defined by a 1.25 transition ratio
• Clock-tunable corner frequency allowing flexible adjustment across a wide range via internal or external clock sources
• Low-power operation with a dedicated shutdown mode that significantly reduces supply current consumption
• Single-supply design optimized for low-voltage applications with minimal output offset voltage

Applications

• ADC anti-aliasing filtering
• DAC post-filtering
• CT2 base stations
• 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 footprint and ensure the temperature grade aligns with the operational environment. Cross-reference the ordering suffix to confirm RoHS compliance status as indicated in the documentation.

Selection Notes

Select this part when a steep roll-off is required within a limited stopband width, as provided by the elliptic response. Ensure the system can provide a stable clock signal, as the corner frequency is directly dependent on the input clock rate. Verify that the single +5V supply voltage meets the system power constraints and that the 3mA operating current fits the power budget.

Part Context

This component belongs to the MAX7418–MAX7425 family of fifth-order switched-capacitor filters. These devices share a common architecture but differ in filter response types and operating voltages. The MAX7421 specifically provides an elliptic response with a 1.25 transition ratio and operates at +5V, distinguishing it from the Bessel and Butterworth variants in the same series.

Replacement Considerations

Compatible substitutes within the same family include the MAX7425, which shares the elliptic response and +5V operation but may differ in specific electrical tolerances or packaging options. Other elliptic variants like the MAX7418 and MAX7422 offer similar functionality with different transition ratios.