AMD XC3S50-4VQ100I

Overview

XC3S50-4VQ100I from AMD (formerly Xilinx) is a Spartan-3 FPGA with 50,000 system gates, 176 logic cells, and 100-pin VQFP package. It operates at -4 speed grade (4.9 ns CLB delay), supports 3.3 V I/O, and includes embedded block RAM and DLLs for clock management. It is used in low-cost industrial control and communication interface logic.

For engineers reviewing the XC3S50-4VQ100I datasheet, pinout, applications, or equivalent options, key selection factors include logic density, I/O voltage compatibility, DLL-based clock deskew capability, and VQFP thermal and routing constraints for cost-sensitive PCB designs.

Technical Context

The XC3S50-4VQ100I implements a configurable logic fabric based on 4-input LUTs and flip-flops per CLB, with dedicated carry logic for arithmetic. It integrates eight 18-kbit block RAMs (total 144 kbits), twelve 18-bit multipliers, and four Digital Clock Managers (DCMs) supporting phase shifting, frequency synthesis, and duty cycle correction.

Configuration is performed via Master Serial mode using external PROM or JTAG boundary-scan. It supports SelectIO standards including LVCMOS, LVTTL, PCI, and SSTL-2, with programmable drive strength and slew rate per I/O bank.

Key Specifications

Pinout & Package

100-pin Very Thin Quad Flat Pack (VQFP), 0.5 mm pitch, 14 mm × 14 mm body size. RoHS-compliant, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar FPGA logic and clock management applications.

Compared with XC3S50-4VQ100I, XC3S100-4VQ100I offers headroom for future firmware expansion while maintaining pin compatibility, whereas XC3S50A-4VQ100C trades industrial reliability for reduced quiescent current and higher maximum operating frequency in benign environments.

Availability

XC3S50-4VQ100I is available at Aetrix Electronics and suitable for industrial automation, communications infrastructure, and embedded display control requiring stable component supply across long-lifecycle programs.

Supply support for XC3S50-4VQ100I includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

AMD acquired Xilinx in 2022 and continues development and support of the Spartan FPGA family. Xilinx pioneered SRAM-based FPGA architecture and configurable logic technology.

The Spartan-3 family was designed for high-volume, cost-sensitive applications requiring reliable logic density, integrated clock management, and flexible I/O - targeting industrial control, video, and communications endpoints.

FAQ

What is the maximum operating junction temperature for XC3S50-4VQ100I?

The XC3S50-4VQ100I is rated for industrial temperature range: –40°C to +100°C junction temperature. This specification is validated per Xilinx DS099 v2.5 and applies under specified thermal conditions with appropriate PCB copper pour and airflow. The XC3S50-4VQ100I must be operated within this range to ensure timing compliance and long-term reliability.

Does XC3S50-4VQ100I support JTAG programming in-system?

Yes, XC3S50-4VQ100I supports IEEE 1149.1 JTAG boundary-scan for in-system programming and debugging. Pins TCK, TMS, TDI, and TDO are dedicated for this function and remain active during configuration and normal operation. The XC3S50-4VQ100I allows full device programming, verification, and test access without requiring external configuration PROM.

How many user I/O pins does XC3S50-4VQ100I provide?

The XC3S50-4VQ100I provides 63 user-configurable I/O pins across four banks. Each bank supports independent VCCO voltage selection (1.2 V to 3.3 V) and programmable drive strength. Unused pins may be configured as inputs with weak pull-up or left unconnected, per Xilinx UG331 guidelines for the XC3S50-4VQ100I.

Can XC3S50-4VQ100I implement a 100 MHz DDR SDRAM controller?

Yes, XC3S50-4VQ100I can implement a 100 MHz DDR SDRAM controller using its DCMs for clock deskew and I/O registers for precise timing alignment. Reference design xapp466 demonstrates this functionality with verified timing closure. The XC3S50-4VQ100I's 63 I/O pins and 144 kbits of block RAM provide sufficient resources for address/command/data paths and command FIFOs.

Is bitstream encryption supported on XC3S50-4VQ100I?

Yes, XC3S50-4VQ100I supports optional AES-128 bitstream encryption when configured via external PROM using the Xilinx iMPACT toolchain. Encryption prevents unauthorized readback and cloning of the programmed logic design. This feature requires enabling security bits during bitstream generation and is documented in Xilinx UG332 for the XC3S50-4VQ100I.