Category: Hardware
Product Number: MAX7301
Hi Team,
We are using the MAX7301 GPIO expander in one of our projects and have completed the schematic and PCB design strictly in accordance with the datasheet recommendations.
As part of our verification activity, we performed signal integrity (SI) analysis assuming operation up to 33 MHz, with the MAX7301 interfaced to an FPGA.
Configuration details:
- MAX7301 → FPGA: GPIOs configured as Push‑Pull Logic Outputs
- FPGA → MAX7301: GPIOs configured as Schmitt Logic Inputs
SI simulation observations:
- From FPGA to MAX7301, we do not observe any SI issues across the full frequency range from 5 MHz to 33 MHz.
- However, from MAX7301 to FPGA, we consistently observe a sawtooth‑shaped waveform, whereas a clean square‑wave signal is expected.
- This behavior remains unchanged across frequencies from 5 MHz up to 33 MHz.
For the analysis, we have used the IBIS model available on the Analog Devices website.
Could you please help clarify:
- Whether this output waveform behavior is expected for MAX7301 GPIOs
- Any known limitations or assumptions in the provided IBIS model
- The maximum recommended GPIO pin toggle speed for the MAX7301 device
- Any design, loading, or termination recommendations to improve the output signal quality
Your support on the above points would be highly appreciated.
Regards,
Yogesh
