MAX7491EEE+

Overview

The MAX7491EEE+T is a dual universal switched-capacitor filter from Analog Devices/Maxim Integrated, housed in a 16-pin QSOP package. It operates on a single +3V supply with a voltage range of 2.7V to 3.6V and supports center frequencies up to 40kHz. The device features two identical 2nd-order filter sections capable of generating bandpass, lowpass, highpass, and notch functions simultaneously. It includes an internal rail splitter for single-supply operation, a low-power shutdown mode drawing less than 1µA, and offers both internal and external clocking options with a fixed 100:1 clock-to-center frequency ratio.

Feature Summary

• Dual 2nd-order filter sections providing simultaneous bandpass, lowpass, highpass, and notch outputs
• Internal rail splitter enabling precise common-mode voltage for single-supply operation
• Low-power shutdown mode reducing supply current to under 1µA
• High accuracy with ±0.2% Q and clock-to-center frequency error

Applications

• Tunable active filters
• Multipole filter cascading
• ADC anti-aliasing
• Post-DAC filtering
• Adaptive filtering and phase-locked loops

Procurement Notes

Verify the specific suffix EEE+ indicates the -40°C to +85°C industrial temperature range and lead-free/RoHS compliance. Confirm the package type is 16-pin QSOP. Check for availability status as distribution may vary. Ensure the ordering information matches the required supply voltage of +3V for the MAX7491 variant.

Selection Notes

Select the MAX7491EEE+ when a single +3V supply is available, as opposed to the MAX7490 which requires +5V. Consider the internal oscillator or external clock requirements based on cutoff frequency stability needs. Evaluate the need for multiple filter topologies within a single package to minimize board space. Verify that the 40kHz maximum center frequency meets the application's signal processing bandwidth.

Part Context

The MAX7491 is part of the MAX7490/MAX7491 family of dual universal switched-capacitor filters. It shares the same pinout and functional architecture as the MAX7490 but is optimized for lower voltage operation at +3V. Both devices utilize a 16-pin QSOP package and offer identical switching capabilities, differing primarily in their power supply specifications and internal biasing characteristics.

Replacement Considerations

The MAX7490 is a pin-compatible alternative requiring a +5V supply instead of +3V. Other MAX749x variants differ by temperature range (CEE+ for commercial) or supply voltage. No direct drop-in replacements exist for different supply voltages without circuit modification.