The XC3S400-4FGG456C is a high-performance, cost-optimized field-programmable gate array (FPGA) from Xilinx (now AMD), part of the popular Spartan-3 family. Designed for high-volume, cost-sensitive applications, this device delivers 400,000 system gates, a 456-pin Fine-Pitch Ball Grid Array (FBGA) package, and a –4 speed grade — making it a go-to solution for embedded systems, consumer electronics, communications, and industrial control designs.
If you are looking for a reliable and affordable Xilinx FPGA with proven performance, the XC3S400-4FGG456C offers an exceptional balance of logic density, I/O flexibility, and embedded memory.
XC3S400-4FGG456C Key Specifications at a Glance
| Parameter |
Value |
| Manufacturer |
Xilinx (AMD) |
| Part Number |
XC3S400-4FGG456C |
| Family |
Spartan-3 |
| System Gates |
400,000 |
| Logic Cells |
8,064 |
| CLBs (Configurable Logic Blocks) |
1,152 |
| Slices |
3,584 |
| Flip-Flops |
7,168 |
| Distributed RAM |
56 Kb |
| Block RAM |
288 Kb (8 × 18 Kb blocks) |
| Multipliers (18×18) |
16 |
| DCMs (Digital Clock Managers) |
4 |
| Maximum User I/Os |
264 |
| Package |
FGG456 (FBGA, 456-pin) |
| Speed Grade |
-4 (Commercial) |
| Operating Voltage (VCCINT) |
1.2 V |
| I/O Voltage |
1.2 V – 3.3 V |
| Operating Temperature |
0°C to +85°C (Commercial) |
| Configuration Interface |
Master Serial, Slave Serial, JTAG, SelectMAP |
| Package Dimensions |
23 × 23 mm |
| RoHS Compliant |
Yes |
What Is the XC3S400-4FGG456C? Product Overview
The XC3S400-4FGG456C belongs to the Xilinx Spartan-3 FPGA series, which was architected specifically for high-volume, low-cost applications without sacrificing performance. The “400” in the part number denotes the 400K system gate count, while “4” indicates the commercial speed grade, “FGG456” specifies the 456-ball fine-pitch BGA package, and “C” confirms the commercial temperature range (0°C to +85°C).
This device is built on a 90 nm process technology, delivering low power consumption while enabling complex logic implementations. Its architecture combines CLBs, dedicated block RAM, digital clock managers, and hardware multipliers to accelerate both control-plane and data-plane logic.
XC3S400-4FGG456C Architecture & Logic Resources
Configurable Logic Blocks (CLBs) and Slices
The FPGA contains 1,152 CLBs, each divided into 4 slices, yielding 3,584 total slices. Every slice includes two 4-input look-up tables (LUTs) and two flip-flops, enabling efficient implementation of arithmetic, state machines, and datapath logic.
Embedded Block RAM
The XC3S400-4FGG456C provides 8 dedicated 18 Kb block RAM tiles for a total of 288 Kb of true dual-port block RAM. Block RAM supports synchronous read/write and can be configured as single-port or dual-port, making it ideal for FIFOs, lookup tables, and data buffers.
Distributed RAM
In addition to block RAM, the LUTs can be configured as 56 Kb of distributed RAM, offering fast, flexible on-chip storage directly within the logic fabric.
Dedicated Multipliers
16 hardware 18×18-bit multipliers are embedded in the device. These dedicated multiply blocks accelerate DSP operations such as FIR filtering, FFTs, and arithmetic-intensive signal processing without consuming LUT resources.
Digital Clock Managers (DCMs)
Four Digital Clock Managers (DCMs) provide clock multiplication, division, phase shifting, and duty-cycle correction. DCMs eliminate clock skew and enable multi-clock designs with clean, synchronized signals.
XC3S400-4FGG456C I/O Capabilities
User I/O Count and Banks
| I/O Bank |
Supported Standards |
| Up to 264 user I/Os |
LVTTL, LVCMOS (1.8V / 2.5V / 3.3V) |
| Differential pairs |
LVDS, LVPECL, BLVDS, ULVDS |
| Single-ended |
PCI, GTL, HSTL, SSTL |
| Pull-up / Pull-down |
Configurable per pin |
| Drive Strength |
2 mA to 24 mA (programmable) |
| Slew Rate Control |
Fast / Slow (configurable) |
The FGG456 package organizes I/O pins into multiple independently-powered banks, allowing different I/O standards to coexist on the same device — a critical advantage for mixed-voltage board designs.
Configuration and Programming Options
The XC3S400-4FGG456C supports multiple configuration modes, offering flexibility for different system architectures:
| Configuration Mode |
Description |
| Master Serial |
Uses external serial Flash (e.g., SPI Flash) |
| Slave Serial |
Controlled by an external host or microprocessor |
| Master SelectMAP (Parallel) |
High-speed parallel configuration |
| Slave SelectMAP |
Parallel mode driven by host processor |
| JTAG (Boundary Scan) |
IEEE 1149.1 compliant; used for programming and debugging |
The JTAG interface supports in-system programming (ISP) and boundary-scan testing, making board-level debugging and programming straightforward.
Electrical Characteristics
| Parameter |
Min |
Typical |
Max |
| VCCINT (Core Voltage) |
1.14 V |
1.20 V |
1.26 V |
| VCCAUX (Auxiliary Voltage) |
2.375 V |
2.50 V |
2.625 V |
| VCCO (I/O Supply) |
1.14 V |
— |
3.465 V |
| Static Current (ICCINTQ) |
— |
~15 mA |
— |
| Operating Temperature |
0°C |
25°C |
+85°C |
Package Information: FGG456 Fine-Pitch BGA
| Package Attribute |
Detail |
| Package Type |
Fine-Pitch Ball Grid Array (FBGA) |
| Pin Count |
456 |
| Body Size |
23 × 23 mm |
| Ball Pitch |
1.0 mm |
| Height (max) |
2.55 mm |
| PCB Pad Recommendation |
Non-Solder Mask Defined (NSMD) |
| Lead-Free / RoHS |
Yes (C suffix = lead-free commercial) |
The compact 23×23 mm footprint makes the FGG456 package suitable for space-constrained PCB layouts, and the 1.0 mm ball pitch is compatible with standard PCB fabrication processes without requiring advanced HDI technology.
XC3S400-4FGG456C vs. Other Spartan-3 Variants
| Part Number |
Gates |
Slices |
Block RAM |
I/Os |
Package |
Speed Grade |
| XC3S200-4FGG256C |
200K |
1,920 |
216 Kb |
173 |
FGG256 |
-4 |
| XC3S400-4FGG456C |
400K |
3,584 |
288 Kb |
264 |
FGG456 |
-4 |
| XC3S1000-4FGG456C |
1,000K |
7,680 |
432 Kb |
391 |
FGG456 |
-4 |
| XC3S1500-4FGG456C |
1,500K |
10,476 |
576 Kb |
391 |
FGG456 |
-4 |
The XC3S400 hits a compelling midpoint — more capable than entry-level Spartan-3 devices, yet significantly more affordable than the XC3S1000 and above. The FGG456 package is shared with larger devices in the family, which simplifies PCB re-use across product tiers.
Typical Applications for XC3S400-4FGG456C
The XC3S400-4FGG456C is widely used across a range of industries and application types:
#### Industrial Automation
- Motor drive controllers and servo amplifiers
- PLC coprocessors and I/O expansion
- Industrial Ethernet bridges (EtherCAT, PROFINET)
#### Communications & Networking
- Protocol conversion between UART, SPI, I²C, and parallel buses
- Line-card logic in telecom equipment
- Network switch fabric acceleration
#### Consumer Electronics
- Set-top box control logic
- Video signal processing (scaling, de-interlacing)
- LCD panel timing controllers
#### Embedded & Computing Systems
- Processor peripheral expansion (custom bus interfaces)
- Glue logic replacement for ASIC-to-PCB integration
- Memory controller bridging (SDRAM, Flash)
#### Defense & Aerospace (Extended-Temp Variants)
- Data acquisition front-ends
- Sensor fusion and interface logic
Design Tools and Support
Xilinx (AMD) provides comprehensive design support for the XC3S400-4FGG456C:
| Tool |
Purpose |
| Xilinx ISE Design Suite |
Primary design environment (HDL synthesis, P&R, bitstream generation) |
| ChipScope Pro |
On-chip debugging via JTAG |
| CORE Generator |
IP core instantiation (FIFOs, memory controllers, DSP) |
| iMPACT |
Device programming and configuration |
| ModelSim / ISim |
HDL simulation |
| PlanAhead |
Floorplanning and timing closure |
Note: While ISE Design Suite is the legacy tool, it remains fully supported for Spartan-3 devices and is available as a free download from the AMD/Xilinx website.
Ordering Information
| Attribute |
Detail |
| Full Part Number |
XC3S400-4FGG456C |
| Manufacturer |
AMD (formerly Xilinx) |
| Manufacturer Series |
Spartan-3 |
| DigiKey Part Number |
122-1442-ND |
| Package / Case |
456-FBGA |
| Operating Temperature Range |
0°C ~ 85°C |
| Moisture Sensitivity Level (MSL) |
3 (168 Hours) |
| Export Control Classification |
EAR99 |
| ECCN |
EAR99 |
| HTS Code |
8542.39.0001 |
Frequently Asked Questions (FAQ)
What does the “-4” speed grade mean on the XC3S400-4FGG456C?
The “-4” designates the commercial speed grade within the Spartan-3 family. Higher numbers correspond to faster timing performance. The –4 grade is the standard commercial option and is suitable for the majority of designs operating at typical clock frequencies up to 200+ MHz for simple paths.
Is the XC3S400-4FGG456C RoHS compliant?
Yes. The “C” suffix in the part number indicates a commercial temperature range (0°C to +85°C) and also confirms that the device is lead-free and RoHS compliant.
What software do I need to program the XC3S400-4FGG456C?
You need the Xilinx ISE Design Suite (version 14.x or earlier) to synthesize, implement, and generate bitstreams for Spartan-3 devices. The iMPACT programmer tool (included in ISE) is used to download the bitstream via JTAG.
Can the XC3S400-4FGG456C be used in industrial temperature applications?
The “C” suffix indicates a commercial grade device (0°C to +85°C). For extended industrial temperature requirements (–40°C to +85°C), Xilinx offered industrial-grade variants with the “I” suffix, such as the XC3S400-4FGG456I.
How much on-chip memory does the XC3S400-4FGG456C have?
The device provides 288 Kb of dedicated block RAM (8 × 18 Kb tiles) plus 56 Kb of distributed RAM accessible through the LUT fabric, for a total of approximately 344 Kb of on-chip RAM.
Summary
The XC3S400-4FGG456C remains a proven, cost-effective FPGA solution for engineers who need reliable programmable logic in a compact BGA package. With 400K system gates, 264 user I/Os, dedicated block RAM, hardware multipliers, and four DCMs, this Spartan-3 device covers a broad spectrum of embedded, industrial, and communications applications. Its 456-pin FGG package enables high pin-count designs while maintaining compatibility with standard PCB manufacturing processes.
For engineers seeking scalability, the FGG456 footprint is pin-compatible with higher-density Spartan-3 devices, protecting your PCB investment as design requirements grow.
