The XC4028XLA-09HQ208I is a high-performance field-programmable gate array (FPGA) from Xilinx’s XC4000XLA family, now part of AMD’s product portfolio. Designed for demanding logic-intensive applications, this device delivers a powerful combination of gate capacity, speed, and I/O flexibility in a compact PQFP package. Whether you are developing embedded control systems, digital signal processing circuits, or industrial automation hardware, the XC4028XLA-09HQ208I offers the programmability and reliability that engineers depend on.

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What Is the XC4028XLA-09HQ208I?

The XC4028XLA-09HQ208I belongs to Xilinx’s mature XC4000XLA series — a line of SRAM-based FPGAs engineered for high-speed logic implementation. The part number breaks down as follows:

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Key Features of the XC4028XLA-09HQ208I

The XC4028XLA-09HQ208I stands out within the Xilinx FPGA product line for its combination of performance and programmability:

• 28,000 usable logic gates with CLB-based architecture
• 2.5V core voltage for reduced power consumption
• Speed grade –9: best-in-class propagation delay performance for the XC4000XLA family
• Industrial temperature range: –40°C to +100°C junction temperature
• 208-pin PQFP package: industry-standard surface-mount footprint
• SRAM-based configuration: fully reprogrammable, infinitely reconfigurable
• Dedicated carry logic and arithmetic support for high-speed math functions
• On-chip RAM: distributed and dedicated block RAM options
• Boundary scan (JTAG): IEEE 1149.1 compliant for simplified board-level testing
• SelectRAM™ technology: flexible, high-performance on-chip memory

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Complete Technical Specifications

Core Electrical Characteristics

Package & Mechanical Specifications

I/O and Connectivity

Memory Resources

Timing Performance (Speed Grade –9)

Note: Exact timing values depend on design implementation and routing. Always verify against Xilinx official datasheet for your specific design constraints.

Environmental & Operating Conditions

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XC4028XLA-09HQ208I vs. Related Part Numbers

Engineers often compare the HQ208 variant with other package and speed options. The table below clarifies key differences:

Key Difference – HQ208 vs HQ240: The HQ208 variant provides 160 user I/O pins while the HQ240 package unlocks up to 192 I/O pins. Choose the HQ208 when board space is constrained; choose the HQ240 when maximum I/O density is required.

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XC4000XLA Architecture Overview

Configurable Logic Blocks (CLBs)

The XC4028XLA’s core logic fabric consists of Configurable Logic Blocks (CLBs) arranged in a regular array. Each CLB contains:

• Two 4-input LUTs (Look-Up Tables) that implement any combinatorial logic function of up to 4 inputs
• Flip-flops: Two D-type flip-flops with clock enable, set, and reset
• Fast carry chain logic: Dedicated hardware carry propagation for arithmetic-intensive operations
• Wide function multiplexers: Allow combining LUT outputs for larger functions
• Local routing resources: Fast intra-CLB connections

SelectRAM™ (Distributed Memory)

The XC4028XLA supports SelectRAM, Xilinx’s patented technology that repurposes CLB LUTs as synchronous or asynchronous RAM blocks. This enables efficient on-chip data buffering without consuming dedicated BRAM resources — particularly useful for FIFO buffers, small lookup tables, and shift registers.

Clock Distribution Network

The FPGA includes a dedicated global clock network with:

• 4 global clock buffers (BUFG primitives) for skew-minimized clock distribution
• Secondary clock routing for multi-clock domain designs
• Low-skew clock insertion across the full device array

Configuration Interface

The XC4028XLA-09HQ208I uses SRAM-based configuration loaded at power-up through one of three modes:

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Applications and Use Cases

The XC4028XLA-09HQ208I is well-suited for a wide range of applications in industrial and embedded markets:

Industrial Automation

Implement programmable logic controllers, motion control state machines, and sensor interface decoders with deterministic timing behavior.

Digital Signal Processing (DSP)

Realize FIR filters, digital mixers, and pipeline arithmetic circuits using the CLB carry chain hardware for high-throughput processing.

Communications & Networking

Implement serial protocol controllers (UART, SPI, I2C, custom protocols), frame synchronizers, and bus bridges.

Test & Measurement Equipment

Deploy the FPGA as a high-speed digital pattern generator, logic analyzer front-end, or protocol decoder in bench instruments.

Embedded Control Systems

Function as a system-level glue logic device in multi-chip designs, managing bus arbitration, interrupt routing, and memory control.

Military & Aerospace (Legacy Systems)

The industrial temperature range and long supply availability make this part suitable for MIL/COTS ruggedized system maintenance and upgrade programs.

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Development Tools & Software Support

Xilinx ISE Design Suite

The XC4028XLA is supported by Xilinx ISE (Integrated Software Environment), specifically ISE 14.7 — the final release of the ISE toolchain. Key capabilities include:

Note: The XC4000XLA series is not supported in Vivado. ISE 14.7, available as a free download from AMD’s support portal, is required for design implementation.

Supported HDL Languages

• VHDL (IEEE Std 1076-1993, 2008 subset)
• Verilog (IEEE Std 1364-2001)
• ABEL (via third-party tools)
• Schematic entry (within ISE Schematic Editor)

Third-Party EDA Tool Support

• Synopsys Synplify Pro
• Mentor Graphics Precision RTL
• Aldec Active-HDL and Riviera-PRO

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PCB Design Considerations

Power Supply Decoupling

Proper decoupling is critical for reliable FPGA operation. Recommended decoupling strategy:

PCB Stack-Up Recommendations

• Dedicate inner layers to VCC and GND planes directly beneath the FPGA
• Minimize via stubs on high-speed I/O signal traces
• Route configuration pins (PROGRAM_B, DONE, INIT_B) with short, clean traces
• Use 50Ω controlled impedance for clock and high-frequency I/O traces

Thermal Management

At the speed grade –9 and full I/O switching, power dissipation should be calculated using Xilinx’s XPower Estimator tool. For the HQ208 PQFP package:

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Ordering Information

Availability Notice: The XC4028XLA series has reached end-of-life (EOL) status from AMD/Xilinx. Stock is available through authorized distributors and specialty electronics suppliers. For guaranteed authenticity, always purchase from authorized or trusted sources and request traceability documentation.

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Frequently Asked Questions (FAQ)

What is the difference between XC4028XLA and XC4028XL?

The XLA variant operates at a 2.5V core voltage and uses a more advanced process node compared to the earlier XL variant (3.3V core). The XLA series delivers lower power consumption and improved speed grades, making it the preferred choice for new designs within the XC4000 family.

Is the XC4028XLA-09HQ208I RoHS compliant?

RoHS compliance depends on the specific lot and date code. Legacy production used tin-lead (SnPb) solder plating. Confirm RoHS status with your distributor at time of purchase and request a Certificate of Conformance if required.

Can I use Vivado to program this FPGA?

No. The XC4000XLA family is not supported by Vivado. You must use Xilinx ISE 14.7 for design synthesis, implementation, and configuration file generation.

What configuration device is compatible with the XC4028XLA?

Xilinx XCFxxS serial PROM devices (e.g., XCF02S, XCF04S) are commonly used for Master Serial configuration. Alternatively, an external microcontroller or processor can drive Slave Serial or SelectMAP configuration modes.

What is the maximum operating frequency?

System performance depends heavily on design complexity and routing. The –9 speed grade supports internal clock frequencies in excess of 80 MHz for pipelined designs, with critical path performance dependent on logic depth and fanout. Use the Timing Analyzer (TRCE) in ISE to verify your specific design.

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Summary

The XC4028XLA-09HQ208I is a proven, high-performance FPGA offering 28,000 gate equivalents, industrial-grade reliability, and the highest available speed grade in the XC4000XLA family — all in a compact 208-pin PQFP surface-mount package. While it is an end-of-life product, it remains an essential component for legacy system maintenance, industrial control upgrades, and cost-effective logic integration in temperature-demanding environments. Engineers requiring reprogrammable, high-speed logic in an industry-standard footprint will find the XC4028XLA-09HQ208I a dependable and capable solution.