MAX7490CEE+T

Overview

The MAX7490CEE+T is a dual universal switched-capacitor filter housed in a 16-pin QSOP package. It operates from a single +5V supply within a voltage range of 4.5V to 5.5V and supports an operating temperature range of 0°C to +70°C. The device features two identical second-order filter sections capable of generating bandpass, lowpass, highpass, and notch functions simultaneously. It supports a center frequency up to 40kHz with a fixed clock-to-center frequency ratio of 100:1. Key electrical parameters include a Q accuracy of ±0.2%, a power-supply current of 3.5mA to 4.0mA, and a shutdown current of less than 1µA.

Feature Summary

• Dual second-order filter sections enable simultaneous generation of multiple standard filter topologies including bandpass, lowpass, highpass, and notch functions.
• High precision performance characterized by tight Q accuracy and minimal clock-to-center frequency error for reliable signal processing.
• Rail-to-rail input and output operation allows for maximum dynamic range utilization in single-supply applications.
• Flexible clocking options support both internal oscillator configuration via external capacitor and precise external clock inputs.

Applications

• ADC anti-aliasing
• Post-DAC filtering
• Tunable active filters

Procurement Notes

Verify the specific ordering suffix CEE against official documentation to confirm the commercial temperature range and lead-free status. Ensure the design accommodates the 16-pin QSOP physical dimensions and thermal requirements. Confirm that the single +5V supply requirement aligns with the system power architecture before finalizing procurement.

Selection Notes

Select this component when dual independent filter channels are required within a compact footprint. The fixed 100:1 clock-to-frequency ratio simplifies design calculations compared to variable-ratio alternatives. Consider the internal rail splitter for simplified single-supply biasing. Evaluate the need for external op-amps if higher-order elliptic or Cauer responses are necessary using Modes 2N or 3A.

Part Context

This part belongs to the MAX7490/MAX7491 family of dual universal switched-capacitor filters. The MAX7490 variant is specifically designed for +5V operation, whereas the MAX7491 supports +3V supplies. Both share identical pinouts and functional capabilities but differ in supply voltage specifications and internal common-mode impedance characteristics.

Replacement Considerations

The MAX7490EEE+ serves as a direct replacement offering the same functionality with an extended industrial temperature range of -40°C to +85°C. Verify that the application environment remains within the 0°C to +70°C range for the CEE variant or upgrade to the EEE variant if wider thermal tolerance is required.

FAQ

How is the center frequency determined?

The center frequency is determined by the clock frequency divided by 100. This can be achieved using an external clock source or an internal oscillator set by an external capacitor connected to the CLK pin.

What is the function of the SHDN pin?

The SHDN pin controls the low-power shutdown mode. Driving it low reduces the supply current to less than 1µA and places the outputs in a high-impedance state. Driving it high enables normal operation.

Can the MAX7490 create fourth-order filters?

Yes, fourth-order filters can be obtained by cascading the two second-order filter sections contained within the single MAX7490 package.