MAX7404CPA+

Overview

The MAX7404CPA+ is an 8th-order, lowpass, elliptic switched-capacitor filter operating from a single +3V supply. It provides a sharp rolloff with a transition ratio of 1.5 and typical stopband rejection of 82dB. The corner frequency is tunable from 1Hz to 10kHz via a 100:1 clock-to-corner ratio using either an external capacitor or an external clock signal. Supply current is 2mA in operating mode and reduces to 0.2µA in shutdown mode. The device features a low output offset voltage of ±5mV and includes an offset adjustment pin for DC level shifting.

Feature Summary

• 8th-order elliptic response with steep rolloff
• Low power consumption with dedicated shutdown mode
• Clock-tunable corner frequency range
• Single-supply operation capability

Applications

• ADC anti-aliasing
• Post-DAC filtering
• Speech processing
• Air-bag electronics
• CT2 base stations

Procurement Notes

Verify the package type matches the required form factor, as this part number indicates an 8-pin Plastic DIP configuration. Confirm the temperature range aligns with operational requirements, noting that the 'C' suffix denotes a commercial range of 0°C to +70°C. Ensure the specific ordering code corresponds to the intended manufacturing lot and revision.

Selection Notes

Select this component when an 8th-order elliptic response is required with a maximum corner frequency of 10kHz. It is suitable for applications needing a transition ratio of 1.5 and high stopband rejection. Choose this part over the MAX7407 if a sharper rolloff (ratio 1.2) is not necessary. Ensure the system operates on a single +3V supply.

Part Context

This device belongs to the MAX7400 family of switched-capacitor filters, which also includes the MAX7400, MAX7403, and MAX7407. While the MAX7400 and MAX7403 operate on +5V supplies, the MAX7404 and MAX7407 are designed for +3V systems. The MAX7404 specifically offers an elliptic response with a transition ratio of 1.5, distinguishing it from the sharper MAX7407.

Replacement Considerations

MAX7404ESA+

FAQ

How is the corner frequency determined?

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

What is the function of the OS pin?

The OS pin allows for offset adjustment. Connecting it to COM sets the default bias, while applying an external voltage enables DC level shifting at the output.

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 into a high-impedance state.