Drop-in replacement for EPCS64SI16N

Hi Korbinian,

Good question — this is a common migration scenario. Let me walk you through the key compatibility points for your EPCS64SI16N → EPCQ64A (EPCQ64ASI16N) transition with the EP4CE55F23C6N.

Package / Pin Compatibility

Pin-to-pin compatibility means the power pins, ground pins, and dedicated pins are at the same locations across devices, and drop-in (vertical migration) compatibility additionally requires that the devices operate at the same voltage level. General · General Both the EPCS64SI16N and EPCQ64ASI16N are 16-pin SOIC packages, so the footprint is the same. For a 16-pin SOIC package, you can migrate vertically from an EPCQ64 device to EPCQ128, EPCQ256, or EPCQ512/A device Config/RSU — and the same SOIC-16 footprint is shared across the EPCS/EPCQ family, so the PCB footprint is compatible.

VCCIO Voltage Requirement — Important!

When using an EPCQ or EPCQA quad-serial configuration device for AS configuration, you cannot connect VCCIO of I/O bank 1 to 2.5 V in Cyclone IV devices, because the minimum VOH of the FPGA is insufficient for driving EPCQ or EPCQA input pins. You must use 3.0 V or 3.3 V for Bank 1 VCCIO when AS configuration with EPCQ or EPCQA devices is used. Cyclone 10 · Config/RSU If your current design already runs Bank 1 at 3.0 V or 3.3 V (which is typical for EPCS-based designs), you're fine. If it's at 2.5 V, that needs to be addressed.

Programming File Compatibility

This is the most important software-side consideration. The programming file compatibility for EPCS and EPCQ to EPCQA devices is as follows for Legacy FPGA devices (which includes Cyclone IV, as it is not a Cyclone V/Arria V/Stratix V device):

• EPCS, 64 Mb and below → .pof/.jic/.rpd/.jam/.jbc: Compatible with EPCQA (any ID check setting)


• EPCS, 64 Mb and below → .svf: Compatible with EPCQA


• EPCQ → .pof/.jic/.rpd/.jam/.jbc: Compatible with EPCQA only if the "Disable EPCS/EPCQ ID check" option is turned ON

Incorrect Programming File Compatibility for EPCS and EPCQ to EPCQA Devices in AN 822: Intel Configuration Device Migration Guideline

Since you're coming from an EPCS64 (not an EPCQ), and Cyclone IV is a legacy device family, your existing .pof/.jic/.rpd/.jam/.jbc programming files should be compatible with the EPCQ64A without needing to change the ID check setting.

IP Core Compatibility

If your design uses any in-system programming or remote update IP cores, note that compatibility varies by IP: the Remote Update IP core is compatible when migrating from EPCS to EPCQ-A devices. Arria 10 · Config/RSU The Serial Flash Controller IP compatibility is listed as Yes/No (conditional) for EPCS to EPCQ-A migration Arria 10 · Config/RSU , so you'd want to verify that specific IP's configuration if you use it.

Cyclone IV GX Speed Grade Note (not applicable here, but FYI)

Cyclone IV GX supports ASI only with -6 and -7 speed grade devices — not all speed grades support ASI. Cyclone IV · Config/RSU Since you're using a Cyclone IV E (EP4CE55), this restriction doesn't apply to you.

Summary

For your EP4CE55F23C6N + EPCS64SI16N design migrating to EPCQ64ASI16N:

• ✅ Same 16-pin SOIC footprint — PCB drop-in compatible


• ✅ Programming files (.pof/.jic/.rpd/.jam/.jbc) are compatible for legacy FPGA devices with EPCS 64 Mb source


• ✅ EPCQ64A uses NOR flash, same as EPCS — functionally equivalent for AS configuration


• ⚠️ Verify Bank 1 VCCIO is 3.0 V or 3.3 V (not 2.5 V)


• ⚠️ If you use any ASMI/SFL IP in-system, verify IP compatibility for your specific IP core

Overall this is a well-supported migration path and your EMS should be able to use the EPCQ64ASI16N as a drop-in replacement, provided the VCCIO check passes. Let me know if you have further questions!