The Xilinx XC7A35T-2FGG484i device belongs to the low-cost, low-power Artix-7 family of FPGAs built on 28nm high-performance, low-power (HPL) process technology. With 33K logic cells, 125MHz DSP slices and 12.5Gbps transceivers, the XC7A35T provides an optimized blend of programmable logic, real-time processing, high-speed I/O and power efficiency ideal for applications including motor control, functional safety, video bridging, software defined radio, broadcast camera links and ultrasound equipment.
This article provides a technical overview of the XC7A35T architecture, available resources, target applications, design flow and benefits for system designers.
XC7A35T-2FGG484i Overview
The Xilinx XC7A35T belongs to the Artix-7 family which spans small to large capacity FPGAs and SoCs supporting space constrained embedded applications. Key attributes include:
- 33K logic cells based on look-up tables (LUTs) as the basic logic building block
- 125MHz DSP slices with 25 x 18 multipliers
- 12 dual-channel gigabit transceivers operating up to 12.5Gbps
- 258 maximum user I/Os
- High speed memory interface supporting DDR3 at up to 1600Mbps
- Configurable mixed-voltage I/O banks
- High performance, low power 28HPL process
The 2FGG484 package designates a compact 17×17 mm 484-ball flip-chip grid array with 1.0mm ball pitch. It provides ample connectivity for embedding the Artix-7 in space constrained embedded systems.
XC7A35T Internal Architecture
The Artix-7 family architecture balances high density programmable logic fabric along with frequently needed hardened blocks for embedded systems.
Programmable Logic Fabric
The core programmable logic is built from slices containing LUTs, flip-flops, multiplexers, arithmetic and wide function generators. Key attributes:
- 6-input LUTs efficiently implement logic functions using only a single LUT per slice
- Flip-flops for sequential logic – register, shift register or latch operation
- Carry logic for arithmetic functions
- Block RAM for distributed memory storage
DSP Slices
The 125 embedded 18×25 multipliers and 48-bit accumulators enable high-performance arithmetic processing.
Block RAM
1.9Mb of distributed 36Kb block RAM provides on-chip data storage with built-in FIFO support.
Transceivers
Up to 12 multirate transceivers operating at up to 12.5Gbps support high-speed serial I/O connectivity.
PCI Express
Two integrated Gen2 PCIe blocks enable direct chip-to-chip communication.
Multi-Standard I/Os
The configurable I/O blocks allow matching electrical interfaces to a wide range of standards including LVDS, HSTL and SSTL.
XC7A35T Target Applications
The XC7A35T is designed to meet the needs of compute-intensive, connectivity-centric embedded systems across industrial, automotive, communications, aerospace/defense and functional safety applications:
Industrial Automation
- Motor drives
- Inverters
- PLC systems
- Process control
- Machine vision
Automotive
- Camera links
- RADAR/LiDAR processing
- Driver assistance systems
- Functional safety
Wireless Infrastructure
Aerospace and Defense
- RADAR and sonar processing
- Communications monitoring
- Video tracking systems
- Encryption/decryption
Test and Measurement
- Protocol analyzers
- Video test signal generators
- High-precision metrology
The cost-optimized programmable logic balanced with integrated processing enables these demanding applications.
XC7A35T-2FGG484i Benefits for Designers
The XC7A35T architecture and capabilities provide hardware engineers with several advantages:
High Performance
- 33K logic cells enables implementation of complex digital logic
- 125MHz DSP slices accelerate math-intensive algorithms
- 12.5Gbps serial connectivity to transfer high-speed data
Power Efficiency
- 28nm process enables low static and dynamic power consumption
- Integrated blocks reduce external components lowering overall system power
Functional Safety
- Configuration CRCs and error detection circuitry improve reliability
Scalability
- Multiple density, I/O and transceiver options within Artix-7 family
Cost
- Mature 28nm process combined with optimized architecture provides low cost
For demanding connectivity-centric embedded systems, the XC7A35T delivers high throughput signal processing coupled with flexible programmable logic at very compelling price points.
XC7A35T Design Flow
Xilinx provides powerful design tools for programming the XC7A35T FPGA:
- Vivado Design Suite – Enables system design, logic synthesis, placement and routing
- Vivado IP Integrator – Connects intellectual property blocks into integrated designs
- SDSoC Development Environment – Supports C/C++ embedded software design
- Vivado HLS – Converts C/C++ code into tuned logic implementations
- System Generator – Implements high-performance DSP designs
- ChipScope Pro – Provides low-level debug capability
The typical design flow involves:
- Create register transfer level (RTL) code defining desired functionality
- Run RTL simulations to verify correct behavior
- Synthesize RTL into Xilinx primitives using Vivado synthesis
- Place and route design to map into XC7A35T physical resources
- Generate bitstream representing complete FPGA configuration
- Program finished bitstream into XC7A35T device
- Validate operation and timing in real system
XC7A35T vs. Larger FPGAs
It is useful to contrast the XC7A35T against higher density FPGAs like the Kintex-7:
Programmable Logic
- XC7A35T offers 33K logic cells using 6-input LUTs
- Kintex-7 provides up to 474K logic cells using 6-input LUTs
Transceivers
- Both support up to 16 transceivers operating at 12.5Gbps
Memory Interfaces
- Both support external DDR3 memory interfaces up to 1600Mbps
DSP Slices
- XC7A35T – 220 DSP slices operating at 125MHz
- Kintex-7 – Up to 3600 DSP slices at 500MHz+
Cost
- XC7A35T optimized for low cost high volume applications
- Kintex-7 costs approximately 40% higher
For applications where power efficiency and unit costs are critical, the XC7A35T offers the ideal programmable logic solution. When maximum performance is mandatory, Kintex-7 provides superior DSP and memory interfacing capabilities.
Conclusion
By integrating abundant I/Os, DSP slices, serial transceivers, block RAM, and PCIe blocks together with cost-optimized programmable logic fabric, the Xilinx XC7A35T-2FGG484i provides an extremely capable chip foundation for next-generation industrial controls, motor drives, functional safety systems, communications infrastructure, test instrumentation and aerospace/defense electronics.
For embedded systems engineers challenged with staying competitive on performance, capabilities, power efficiency and unit costs, the Artix-7 family offers an invaluable platform for accelerating innovation and progress from concept to deployed solution.
Frequently Asked Questions
Q: What is the Xilinx XC7A35T FPGA?
A: It is a low-cost, low-power Artix-7 series FPGA with 33K logic cells, 125MHz DSP blocks and 12.5Gbps transceivers built on a 28nm fabrication process.
Q: What are some key components of the XC7A35T architecture?
A: This includes programmable logic fabric using 6-input LUTs, 220 DSP slices, 1.9Mb of block RAM, up to 16 transceivers, PCIe blocks, and configurable mixed-voltage I/O.
Q: What kinds of applications can the XC7A35T FPGA address?
A: Target applications span industrial automation, motor drives, functional safety systems, wireless infrastructure, broadcast video, test instrumentation.
Q: How does the XC7A35T compare against larger FPGAs like Kintex-7?
A: Kintex-7 offers approximately 40% higher logic capacity and performance but at a greater cost. XC7A35T optimizes cost and power efficiency.
Q: What design tools support programming XC7A35T FPGAs?
A: Xilinx’s Vivado Design Suite supports the end-to-end flow from RTL design entry to layout and implementation culminating in bitstream generation.
