The Xilinx XC3S400-4TQG144C is a mid-density member of the Spartan-3 FPGA family, offering 400,000 system gates and 8,064 logic cells in a 144-pin TQFP package. Built on 90 nm CMOS technology and operating at a core voltage of 1.2 V, this device delivers an internal clock speed of up to 630 MHz, providing a cost-effective programmable logic platform for applications requiring higher logic density than the entry-level Spartan-3 devices.

Architecture

The XC3S400-4TQG144C features 8,064 logic cells organised into 896 configurable logic blocks (CLBs). Each CLB contains four slices, each slice containing two 4-input look-up tables (LUTs) and two flip-flops. The hierarchical SelectRAM memory architecture includes 288 Kbits of block RAM and distributed RAM, totalling 294,912 bits of on-chip memory. The device also includes four 18x18 dedicated multipliers for digital signal processing acceleration, enabling efficient implementation of arithmetic functions and filtering algorithms.

I/O and Clock Management

The device provides 97 user I/O pins supporting a wide range of single-ended and differential signalling standards, including LVCMOS, LVTTL, HSTL, SSTL, LVDS, and RSDS. SelectIO technology allows flexible I/O voltage selection per bank, supporting 3.3V, 2.5V, 1.8V, 1.5V, and 1.2V signalling. Four Digital Clock Managers (DCMs) provide precise clock management capabilities including clock skew elimination, frequency synthesis, phase shifting, and clock distribution. The device features eight low-skew global clock networks plus additional clocks per half device.

Technical Specifications

Packaging and Environmental

The XC3S400-4TQG144C is housed in a 144-pin TQFP (Thin Quad Flat Pack) package measuring 20 x 20 mm with a 0.5 mm pitch. The package is RoHS compliant (ROHS3) and REACH unaffected. Moisture Sensitivity Level is MSL 3, requiring a floor life of 168 hours after opening. The device is supplied in tray packaging with 60 pieces per tray. Country of origin is Taiwan. EAN: 4099879145345.

Development Support

Supported by Xilinx ISE WebPACK and ISE Design Suite (ISE 14.7). The device is not supported by the newer Vivado toolchain. Programming is performed via JTAG (IEEE 1149.1) using standard cables. The device also supports Slave Serial and Master Serial configuration modes, as well as Boundary-Scan testing.

Product Status

The XC3S400-4TQG144C is marked as obsolete by DigiKey. Stock is limited and the device is no longer in active production. For existing designs, verify supply availability before committing to volume production. For new designs requiring similar density, consider newer families such as Spartan-6, Spartan-7, or Artix-7.