XC18V256VQ44C

Overview

The XC18V256VQ44C is a 3.3V in-system programmable configuration PROM from the Xilinx XC18V00 series, housed in a 44-pin VQFP package. It provides 256-Kbit (262,144 bits) of non-volatile storage for FPGA bitstreams. The device supports IEEE Std 1149.1 JTAG boundary-scan and in-system programming with an endurance of 20,000 program/erase cycles. It features dual configuration modes: Master/Slave Serial and Slave-Parallel/SelectMAP. I/O pins are 5V tolerant, allowing compatibility with 5V, 3.3V, and 2.5V signals.

Feature Summary

• Supports in-system programming via standard 4-pin JTAG protocol for efficient design iterations without package handling.
• Enables cascading of multiple devices using the CEO output to drive the CE input of downstream PROMs for larger configurations.
• Incorporates advanced data security features, including user-programmable read inhibition via JTAG to protect against unauthorized copying.
• Features 5V tolerant I/Os that accept 5V, 3.3V, and 2.5V signals, ensuring immunity to power supply sequencing issues.

Applications

• Configuration of Xilinx Spartan-II and Spartan-IIE FPGAs
• Configuration of Xilinx Virtex-II FPGAs
• System-in-package designs requiring reprogrammable configuration memory

Procurement Notes

Verify the specific suffix 'VQ44' corresponds to the 44-pin VQFP package as documented in the official datasheet. Confirm the device family is XC18V00 and not a one-time programmable variant like XC17V00. Ensure the source documentation explicitly lists XC18V256VQ44C as a supported part number within the XC18V00 series specifications.

Selection Notes

Select this component when designing systems with Xilinx FPGAs requiring reprogrammable configuration storage. It is suitable for applications needing serial or parallel configuration interfaces. Consider cascading capabilities if the target FPGA configuration exceeds 256-Kbit. Verify voltage compatibility, noting the 3.3V core with 5V tolerant I/Os.

Part Context

The XC18V256VQ44C belongs to the Xilinx XC18V00 series of in-system programmable configuration PROMs. This series includes devices ranging from 256-Kbit to 4-Mbit capacities. These PROMs are designed specifically to store and provide configuration bitstreams for various Xilinx FPGA families, offering a cost-effective method for storing large configuration data.

Replacement Considerations

Compatible replacements within the same family include other XC18V00 series devices such as XC18V512VQ44C or XC18V01VQ44C, provided the capacity meets the FPGA requirements. Devices from the XC17V00 one-time programmable family are functionally similar but lack in-system reprogrammability.