XC18V256PC20C

Overview

The XC18V256PC20C is a 3.3V in-system programmable configuration PROM from the XC18V00 series, featuring a 256-Kbit (262,144-bit) capacity. It supports IEEE Std 1149.1 JTAG boundary-scan for programming and configuration initiation. The device offers dual configuration modes: serial (up to 33 MHz) and parallel (up to 264 Mb/s at 33 MHz). It provides 5V tolerant I/Os, allowing compatibility with 5V, 3.3V, and 2.5V signals, while outputting 3.3V or 2.5V data. Endurance is rated for 20,000 program/erase cycles with 20-year data retention. It is available in PC20, SO20, PC44, and VQ44 packages.

Feature Summary

• Supports in-system programming via standard 4-pin JTAG protocol for efficient design iterations without package handling.
• Features 5V tolerant I/O pins that accept 5V, 3.3V, and 2.5V signals, ensuring immunity to power supply sequencing issues.
• Enables cascading of multiple devices using the CEO output to drive the CE input of subsequent PROMs for larger bitstreams.
• Incorporates advanced data security features to prevent unauthorized reading of programming patterns via JTAG.

Applications

• Configuration of Xilinx FPGAs and CPLDs in Master Serial mode
• Configuration of Xilinx FPGAs in Slave Parallel or Slave-SelectMAP modes
• In-system programming and verification of FPGA configuration bitstreams

Procurement Notes

Verify the specific package type required, as the model suffix PC20 indicates a Plastic Chip Carrier package. Confirm compatibility with the target FPGA's configuration mode (Serial, Parallel, or SelectMAP). Ensure the design accounts for the 20,000 cycle endurance limit if frequent reprogramming is anticipated. Check that the JTAG interface supports the required IDCODE and CONFIG instructions for proper initialization.

Selection Notes

Select this device when a 256-Kbit capacity is sufficient for the target FPGA configuration bitstream. Choose the PC20 package if space constraints allow for its footprint compared to smaller SO20 options. Consider cascading with other XC18V00 family members if the bitstream exceeds 256 Kbits. Ensure the system voltage levels align with the 5V tolerant inputs and 3.3V/2.5V outputs.

Part Context

The XC18V256PC20C belongs to the XC18V00 series of in-system programmable configuration PROMs. This series includes devices ranging from 256-Kbit to 4-Megabit capacities. These PROMs are designed specifically to store and provide configuration data for Xilinx FPGAs and CPLDs, offering a cost-effective method for storing large bitstreams.

Replacement Considerations

Compatible replacements within the same family include XC18V256PC44, XC18V256SO20, and XC18V256VQ44, which offer the same capacity but different package types. For larger capacities, XC18V512 or XC18V01 can be used, potentially requiring cascading or single-device substitution depending on bitstream size.