The XC3S400-5FGG320C is a high-performance, cost-efficient Field Programmable Gate Array (FPGA) from AMD Xilinx’s Spartan-3 family. Designed for high-volume, cost-sensitive applications, this device delivers powerful logic density, flexible I/O options, and proven 90nm process technology — all in a compact 320-pin Fine-Pitch Ball Grid Array (FBGA) package. Whether you’re building embedded systems, industrial controls, or communications hardware, the XC3S400-5FGG320C offers a compelling balance of performance and value.
What Is the XC3S400-5FGG320C?
The XC3S400-5FGG320C is part of Xilinx’s Xilinx FPGA Spartan-3 product line — a family engineered to provide a superior, reconfigurable alternative to mask-programmed ASICs. Unlike traditional ASICs, this FPGA eliminates the high NRE (Non-Recurring Engineering) costs and long development cycles. Designers can reprogram the device in the field without any hardware replacement, dramatically shortening time-to-market.
Built on 90nm process technology and operating at a 1.2V core voltage, the XC3S400-5FGG320C incorporates numerous architectural advances derived from Xilinx’s Virtex-II platform, setting new standards in programmable logic performance per dollar.
Key Features of the XC3S400-5FGG320C
- 400K system gate capacity with 8,064 logic cells
- 90nm CMOS process technology for low power and high speed
- 1.2V core supply voltage
- 320-pin Fine-Pitch Ball Grid Array (FBGA) package
- Up to 264 user I/O pins
- Support for multiple single-ended and differential I/O standards (LVDS, HSTL, SSTL)
- Embedded block RAM for high-bandwidth data storage
- Dedicated hardware multipliers for DSP operations
- Digital Clock Managers (DCMs) for precise clock control
- Five programmable logic functional elements per slice
- Static CMOS configuration latches (CCLs) for robust reprogrammability
- Commercial temperature grade (0°C to +85°C)
XC3S400-5FGG320C Full Technical Specifications
General Specifications
| Parameter |
Value |
| Manufacturer |
AMD (Xilinx) |
| Part Number |
XC3S400-5FGG320C |
| FPGA Family |
Spartan-3 |
| Process Technology |
90nm |
| System Gates |
400,000 |
| Logic Cells |
8,064 |
| Core Supply Voltage (VCC INT) |
1.2V |
| Package Type |
FBGA (Fine-Pitch Ball Grid Array) |
| Pin Count |
320 |
| RoHS Compliance |
Not Compliant (standard; ‘G’ suffix = Pb-free) |
| Temperature Grade |
Commercial (0°C to +85°C) |
| Speed Grade |
-5 |
Logic Resources
| Resource |
Quantity |
| Logic Cells |
8,064 |
| CLB Slices |
3,584 |
| Flip-Flops |
7,168 |
| Maximum Distributed RAM |
56 Kbits |
| Block RAM (18 Kbit blocks) |
16 blocks (288 Kbits total) |
| Dedicated Multipliers (18×18) |
16 |
| Digital Clock Managers (DCMs) |
4 |
I/O and Packaging
| Parameter |
Value |
| Package |
FGG320 / FBGA-320 |
| Total Package Pins |
320 |
| Maximum User I/O |
264 |
| I/O Standards Supported |
LVCMOS, LVTTL, LVDS, HSTL, SSTL, PCI, GTL+ |
| Differential I/O Pairs |
Supported |
Electrical Characteristics
| Parameter |
Value |
| Core Voltage (VCCINT) |
1.2V |
| Auxiliary Voltage (VCCAUX) |
2.5V or 3.3V |
| I/O Bank Voltage (VCCO) |
1.2V to 3.3V (bank-configurable) |
| Operating Temperature (Commercial) |
0°C to +85°C |
XC3S400-5FGG320C Ordering Information
| Field |
Detail |
| Part Number |
XC3S400-5FGG320C |
| Series |
Spartan-3 |
| Speed Grade |
-5 (fastest commercial speed grade) |
| Package Code |
FGG320 (320-ball FBGA, Pb-free) |
| Temperature |
C = Commercial (0°C to +85°C) |
| DigiKey Part # |
1951726 |
| Manufacturer |
AMD (formerly Xilinx) |
Note on Part Number Decoding: XC3S 400 = 400K gates · 5 = speed grade · FGG = Pb-free FBGA package · 320 = 320 pins · C = Commercial temperature range.
Spartan-3 Architecture: How the XC3S400-5FGG320C Works
Configurable Logic Blocks (CLBs)
The XC3S400-5FGG320C is built around an array of Configurable Logic Blocks, each containing four slices. Every slice pairs two look-up tables (LUTs) with two flip-flops, enabling highly efficient implementation of logic functions, arithmetic operations, and shift registers. The distributed RAM capability of the LUTs provides fast, low-latency storage for small data sets.
Block RAM
The device includes 16 dedicated 18-Kbit block RAM modules, totaling 288 Kbits of true dual-port SRAM. Each block supports independent read and write widths, making it ideal for FIFOs, data buffers, lookup tables, and embedded processor memories.
Dedicated Multipliers
Sixteen 18×18-bit dedicated hardware multipliers are integrated beside the block RAM columns. These enable efficient implementation of DSP functions such as FIR filters, correlators, and transform algorithms without consuming CLB resources.
Digital Clock Managers (DCMs)
Four Digital Clock Managers provide fully digital clock synthesis, phase shifting, and frequency division/multiplication. DCMs eliminate clock skew across the device and support dynamic phase adjustment — a key feature for high-speed interface designs.
I/O Architecture
The XC3S400-5FGG320C supports a wide range of I/O standards organized into independently configurable I/O banks. Each bank’s VCCO pin sets the voltage level for that group of I/Os, enabling a single device to interface with multiple voltage domains simultaneously. Supported standards include LVDS, HSTL, SSTL, LVCMOS, LVTTL, GTL+, and PCI.
Configuration Modes
The Spartan-3 FPGA supports five configuration modes for maximum design flexibility:
| Mode |
Description |
| Master Serial |
Device reads configuration from an external serial PROM |
| Slave Serial |
Configuration data is driven by an external controller |
| Master Parallel (SelectMAP) |
High-speed parallel configuration from processor or CPLD |
| Slave Parallel (SelectMAP) |
Parallel configuration under external control |
| JTAG (Boundary Scan) |
IEEE 1149.1-compliant programming and debug |
Configuration data is stored in robust reprogrammable static CMOS configuration latches (CCLs). At power-up, the FPGA loads its configuration from an external non-volatile source (e.g., a serial Flash or Platform Flash PROM).
Typical Applications
The XC3S400-5FGG320C’s combination of gate density, embedded memory, and flexible I/O makes it well-suited for a broad range of applications:
| Industry |
Typical Use Cases |
| Communications |
Protocol bridging, line cards, data framing, SONET/SDH interfaces |
| Industrial Automation |
Motor control, sensor fusion, real-time control loops |
| Consumer Electronics |
Home networking, display controllers, set-top boxes |
| Embedded Systems |
Custom CPU/peripheral integration, co-processing |
| Test & Measurement |
Pattern generation, data capture, signal analysis |
| Automotive |
Body electronics, driver assistance systems (AEC-Q100 variants) |
| Medical |
Imaging systems, patient monitoring, data acquisition |
XC3S400-5FGG320C vs. Other Spartan-3 Devices
| Device |
System Gates |
Logic Cells |
Block RAM (Kbits) |
Multipliers |
Max I/O |
| XC3S50 |
50K |
1,728 |
72 |
4 |
124 |
| XC3S200 |
200K |
4,320 |
216 |
12 |
173 |
| XC3S400 |
400K |
8,064 |
288 |
16 |
264 |
| XC3S1000 |
1,000K |
17,280 |
432 |
24 |
391 |
| XC3S1500 |
1,500K |
29,952 |
648 |
32 |
487 |
| XC3S2000 |
2,000K |
46,080 |
1,008 |
96 |
565 |
The XC3S400 occupies the sweet spot in the Spartan-3 lineup — offering substantially more resources than the XC3S200 while remaining far more cost-effective than the XC3S1000 and above.
Available Package Options for XC3S400
| Package |
Pin Count |
Type |
Max User I/O |
| TQ(G)144 |
144 |
Thin Quad Flat Pack (TQFP) |
97 |
| PQ(G)208 |
208 |
Plastic Quad Flat Pack (PQFP) |
141 |
| FT(G)256 |
256 |
Fine-Pitch Thin BGA (FTBGA) |
173 |
| FG(G)320 |
320 |
Fine-Pitch BGA (FBGA) |
264 |
| FG(G)456 |
456 |
Fine-Pitch BGA (FBGA) |
264 |
The FGG320 package (used in the XC3S400-5FGG320C) provides the highest I/O count available in a 320-ball format, with the ‘G’ suffix confirming the Pb-free (RoHS) solder ball composition.
Design Tools & Software Support
The XC3S400-5FGG320C is supported by AMD Xilinx’s full suite of FPGA design tools:
| Tool |
Purpose |
| Xilinx ISE Design Suite |
Legacy synthesis, implementation, and bitstream generation |
| Vivado Design Suite |
Modern design flow (limited Spartan-3 support; ISE recommended) |
| CORE Generator |
IP core instantiation for common functions (FIFOs, memories, DSP) |
| ChipScope Pro |
In-system logic analysis via JTAG |
| iMPACT |
JTAG-based device programming |
| ModelSim / XSIM |
RTL and gate-level simulation |
Tip: For Spartan-3 devices, Xilinx ISE 14.7 is the recommended design suite. It is available as a free download from AMD Xilinx and provides full support for synthesis, place-and-route, and bitstream generation.
Why Choose the XC3S400-5FGG320C?
ASIC Alternative with Zero NRE Costs
The Spartan-3 platform was purpose-built as a cost-effective alternative to mask-programmed ASICs. The XC3S400-5FGG320C eliminates million-dollar NRE fees and month-long fabrication cycles, letting teams iterate on hardware design rapidly and affordably.
In-Field Programmability
Because configuration is stored in external non-volatile memory (loaded at power-up), the FPGA’s functionality can be updated in the field by simply reprogramming the configuration PROM — no hardware changes required. This is invaluable for bug fixes, feature additions, and product differentiation across hardware revisions.
Proven Spartan-3 Ecosystem
With millions of units shipped across thousands of designs, the Spartan-3 platform has a deep ecosystem of reference designs, IP cores, community resources, and third-party hardware. The XC3S400-5FGG320C is backed by mature toolchain support and comprehensive documentation from AMD Xilinx.
-5 Speed Grade: Maximum Commercial Performance
The “-5” speed grade designates the fastest available commercial variant of the XC3S400 device, making it ideal for designs where timing margins are critical.
Frequently Asked Questions (FAQ)
Q: What is the difference between XC3S400-5FGG320C and XC3S400-5FG320C?
The “FGG” variant uses Pb-free (lead-free) solder balls compliant with RoHS requirements, while the “FG” variant uses standard leaded solder. The extra “G” in the package code denotes the Pb-free option.
Q: Is the XC3S400-5FGG320C RoHS compliant?
The XC3S400-5FGG320C uses a Pb-free package (designated by the double “GG” in the part number). However, RoHS compliance status should be confirmed with your distributor, as it depends on the full bill of materials.
Q: What configuration PROM is compatible with the XC3S400-5FGG320C?
Common options include the Xilinx XCF04S (Platform Flash), XCF08P, or third-party SPI Flash devices supported via the Master Serial configuration mode.
Q: Can I use Vivado to program the XC3S400-5FGG320C?
Full design flow support for Spartan-3 is provided by Xilinx ISE 14.7. Vivado does not support Spartan-3 for synthesis and implementation, though iMPACT (part of ISE) can still be used for device programming.
Q: What is the maximum user I/O count for the XC3S400-5FGG320C?
In the FGG320 package, the XC3S400 supports up to 264 user I/O pins, the highest available in this package size.
Summary
The XC3S400-5FGG320C is a mature, well-documented, and cost-optimized FPGA that continues to serve as a reliable design foundation for engineers worldwide. With 400K gates, 8,064 logic cells, 16 block RAMs, 16 dedicated multipliers, 4 DCMs, and up to 264 user I/Os in a 320-ball Pb-free FBGA package, it delivers a strong feature set for its price point. The -5 speed grade ensures designers get the best commercial timing performance available in this device family.
For any project requiring a programmable logic solution with proven silicon, a rich ecosystem, and the flexibility to evolve post-deployment, the XC3S400-5FGG320C remains an excellent choice.
