Forum Discussion
JohnT_Altera
Regular Contributor
23 days agoHi,
- Is this approach correct?
Can 3.3 V LVTTL/LVCMOS signals be safely interfaced to an FPGA I/O bank powered at 3.0 V without violating input tolerance or causing long‑term reliability issues?- Yes, you are correct.
- What about FPGA outputs?
If the FPGA bank is powered at 3.0 V VCCIO, and the FPGA drives LVTTL/LVCMOS outputs to external circuitry that expects 3.3 V levels, will this work reliably?- Are the VOL/VOH levels still compliant?
- You will need to check the ViL and ViH of the device to see if it is meeting the specs.
- Are there any risks of reduced noise margin?
- Please follow the guideline mention on the termination resistors.
- Are the VOL/VOH levels still compliant?
- In summary:
- Is powering the bank at 3.0 V a valid method to avoid adding series termination?
- If you are using 3.3V IO standard then it is recommended to use 3.3V VCCIO.
- https://docs.altera.com/v/u/docs/654327/cyclone-iv-device-handbook-volume-3-device-datasheet
- What are the recommended practices for LVTTL/LVCMOS signaling in Cyclone IV E when the external system uses 3.3 V levels?
- I would recommend to the same IO Standard as the external systems.
- Is powering the bank at 3.0 V a valid method to avoid adding series termination?
Thanks.
YogeshaDG
New Contributor
23 days agoHi JohnT_Altera for the Valuable comments. i appreciate the time and effort you put in.