MAX7491CEE+

Overview

The MAX7491CEE+ 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 an operating temperature range of 0°C to +70°C. The device features two identical 2nd-order filter sections capable of generating bandpass, lowpass, highpass, and notch functions simultaneously. It achieves a center frequency up to 40kHz with a clock-to-center frequency ratio of 100:1 and offers Q accuracy within ±0.2%.

Feature Summary

• Dual 2nd-order filter sections integrated into a compact 16-pin QSOP package
• High accuracy performance with ±0.2% Q and clock-to-center frequency error
• Rail-to-rail input and output operation for wide dynamic range
• Supports internal or external clocking for flexible cutoff frequency control

Applications

• Tunable Active Filters
• Multipole Filters
• ADC Anti-Aliasing
• Post-DAC Filtering
• Adaptive Filtering

Procurement Notes

Verify the specific suffix CEE+ against official documentation to confirm the commercial temperature range (0°C to +70°C) and lead-free/RoHS compliance status. Ensure the single +3V supply requirement aligns with system power constraints. Cross-reference the 16-pin QSOP package dimensions with PCB layout guidelines to guarantee mechanical fit and thermal performance during integration.

Selection Notes

Select the MAX7491 over the MAX7490 when the application requires a single +3V supply instead of +5V. Verify that the required center frequency falls within the 40kHz maximum limit. Consider cascading multiple units if higher-order filtering than the built-in dual 2nd-order sections is necessary. Confirm that the external resistor values used for setting Q and gain are compatible with the device's input impedance characteristics.

Part Context

The MAX7491 belongs to the MAX749x family of dual universal switched-capacitor filters manufactured by Maxim Integrated, now part of Analog Devices. This series provides versatile analog filtering solutions in a small footprint. The MAX7491 specifically targets low-voltage applications requiring precise frequency response without the need for large external passive components typically found in RC active filters.

Replacement Considerations

MAX7490CEE+ (identical functionality with +5V supply)

FAQ

How is the center frequency determined?

The center frequency is determined by the clock frequency applied to the CLK pin, maintaining a fixed 100:1 ratio (fO = fCLK / 100).

Can the MAX7491 operate with dual supplies?

Yes, by connecting the COM pin to system ground and the GND pin to the negative supply, allowing use with ±1.5V rails.

What is the purpose of the SHDN pin?

Driving the SHDN pin low activates a low-power shutdown mode, reducing supply current to less than 1µA and placing outputs in a high-impedance state.