XCV50-5BG256I FPGA: A Technical Guide to the Legacy Virtex Workhorse

In the world of industrial electronics repair and maintenance, finding technical data on legacy components is often harder than finding the part itself. The XCV50-5BG256I is a prime example. As a member of the original Xilinx Virtex family (released in 1998), this FPGA powered the first wave of high-performance digital telecommunications and industrial control systems.

While it has long been superseded by the Virtex-7, UltraScale, and Versal families, the XCV50 remains a critical component for the MRO (Maintenance, Repair, and Operations) market. Engineers maintaining 20-year-old wafer fabs, medical imaging devices, or aerospace test equipment rely on this specific chip to keep billion-dollar lines running.

This guide is your technical resource for the XCV50-5BG256I, breaking down its datasheet specifications, pinout quirks, and the legacy software environment required to program it in 2025.

1.0 What is the XCV50-5BG256I? (Datasheet Explained)

The XCV50-5BG256I is a Field-Programmable Gate Array (FPGA) from the original Xilinx Virtex series. It is an SRAM-based device, meaning it is reconfigurable and volatile (loses data when power is cut).

1.1 The Original Xilinx Virtex Family: The 2.5V Revolution

When the Virtex family launched, it marked a significant shift in FPGA technology. It moved the industry away from 5V cores to a **2.5V core architecture**, allowing for higher density and lower power consumption. * **System Gates:** The family ranged from 50k to 1M system gates. * **DLLs:** It introduced Delay-Locked Loops (DLLs) for advanced clock management, a feature that is now standard in all FPGAs. * **BlockRAM:** It featured dedicated on-chip block memory, crucial for buffering data.

1.2 Decoding the Part Number: XCV50-5BG256I

Understanding the part number is vital for ensuring compatibility, especially regarding temperature and speed.

• XCV: Family (Xilinx Virtex).
• 50: Density (50,000 System Gates).
• -5: Speed Grade (Standard/Medium Speed). Older datasheets listed -4 (slowest), -5, and -6 (fastest).
• BG: Package Type (Ball Grid Array - Standard 1.27mm pitch).
• 256: Pin Count (256 balls).
• I: Temperature Grade (Industrial: -40°C to +100°C). Note: Commercial 'C' grade parts are rated 0°C to 85°C.

1.3 Obsolescence Status: Critical MRO Component

> **Status: OBSOLETE / END-OF-LIFE (EOL)** > > The XCV50-5BG256I is **obsolete**. Xilinx (now AMD) stopped manufacturing these wafers years ago. > > **Implication:** You cannot buy this part from franchise distributors like Digi-Key or Mouser. It is available only through independent distributors and stock specialists like **AichipLink**. Be extremely wary of counterfeits; sourcing form a reputable legacy supplier is non-negotiable.

2.0 XCV50-5BG256I Key Technical Specifications

When replacing this chip, you must match the specifications exactly, particularly the voltage and package type.

2.1 Core Logic, Gates, and Memory Specs

Feature	Specification
System Gates	57,906
Logic Cells	1,728
CLB Array	16 x 24
Total Block RAM	32,768 bits (32k)
Max User I/O	180
Delay-Locked Loops (DLLs)	4
Architecture	SRAM-based (Volatile)

2.2 Operating Voltage: 2.5V Core Importance

The Virtex family uses a split-voltage architecture. Mixing this up will destroy the chip. * **VCCINT (Core Voltage):** **2.5V** (±5%). This powers the internal logic. * **VCCO (I/O Voltage):** **3.3V, 2.5V, or 1.5V**. Each I/O bank can be powered independently to interface with different logic standards (LVTTL, LVCMOS, GTL, etc.).

Warning: Do not apply 5V to the core VCCINT pins. While some inputs may be 5V tolerant depending on configuration, the core supply is strictly 2.5V.

3.0 Pinout and Package Details (BG256)

The BG256 is a standard Ball Grid Array package with a 1.27mm ball pitch.

3.1 Understanding the 256-Ball BGA Package

* **Grid:** The balls are arranged in a grid (A1 to T20). * **Mounting:** Surface Mount Technology (SMT). Replacing this chip requires a BGA rework station; it cannot be done with a standard soldering iron. * **Industrial Grade:** The "I" suffix means the package and die are tested to withstand harsh thermal cycling (-40°C to +100°C), common in industrial cabinets.

3.2 Key Pin Functions: VCCINT, VCCO, and JTAG

When troubleshooting a board with this FPGA, check these pins first: * **VCCINT:** Core power (2.5V). * **VCCO:** I/O bank power (Check board schematic, often 3.3V). * **GND:** Ground. * **JTAG (TCK, TMS, TDI, TDO):** The interface used for testing and programming. * **PROGRAM_B:** Active Low configuration reset. If this pin is held low, the FPGA is held in a reset state. * **DONE:** Goes High when configuration is complete. **If DONE is low, the FPGA is not working.**

4.0 Programming and Maintenance Guide

You have a replacement chip, but how do you get the code onto it?

4.1 Required Software: Legacy Xilinx ISE

You **cannot** use the modern Xilinx Vivado software suite for the Virtex XCV50. * **Required Software:** **Xilinx ISE (Integrated Software Environment)**. * **Version:** ISE 14.7 (Legacy version for Windows 10/Linux) or older versions like ISE 10.1 are typically used. * **Cable:** A Xilinx Platform Cable USB (or clone) is required for JTAG programming.

4.2 Configuration: SRAM and PROMs

Since the XCV50 is volatile, it must load its configuration data every time it powers up. * **Configuration PROM:** Usually paired with a legacy Xilinx PROM like the **XC1700** series (OTP) or **XC18V00** series (Flash). * **Process:** Upon power-up, the FPGA enters "Master Serial" mode and clocks data out of the PROM. If the PROM is dead, the FPGA will never configure.

4.3 Replacement Strategy for Industrial Systems

If you have a failed XCV50-5BG256I: 1. **Verify the Speed/Temp:** Ensure you buy an **"I" (Industrial)** grade if the original was industrial. A Commercial ("C") grade part may fail in a hot factory cabinet. 2. **Check the Speed Grade:** You can usually replace a slower **-4** with a faster **-5** or **-6**, but you cannot safely replace a faster chip with a slower one. 3. **Source Genuine:** Use a distributor that offers X-ray inspection to ensure the internal die matches the package markings.

In Conclusion

The XCV50-5BG256I is a legend of the FPGA world. While it may be two decades old, its role in keeping critical industrial infrastructure operational cannot be overstated. Understanding its 2.5V architecture, BGA package constraints, and the need for legacy ISE software is essential for any engineer tasked with maintaining equipment from this era.

If you are facing a line-down situation and need this hard-to-find part, don't gamble on unverified sources. Explore our inventory of legacy FPGAs or contact AichipLink today to secure genuine, tested components for your repair needs.

 

 

 

 

 

Written by Jack Elliott from AIChipLink.

 

AIChipLink, one of the fastest-growing global independent electronic   components distributors in the world, offers millions of products from thousands of manufacturers, and many of our in-stock parts is available to ship same day.

 

We mainly source and distribute integrated circuit (IC) products of brands such as Broadcom, Microchip, Texas Instruments, Infineon, NXP, Analog Devices, Qualcomm, Intel, etc., which are widely used in communication & network, telecom, industrial control, new energy and automotive electronics. 

 

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