Lattice LC4256V-5TN100C: A Comprehensive Technical Overview of the CPLD

The Lattice LC4256V-5TN100C represents a significant member of the high-performance, low-power ispXP CPLD family from Lattice Semiconductor. This complex programmable logic device (CPLD) is engineered to bridge the gap between simple PLDs and larger FPGAs, offering an optimal blend of density, speed, and non-volatility for a wide array of control-oriented and glue logic applications.

Core Architecture and Key Features

At the heart of the LC4256V lies a robust and flexible architecture. Its core consists of a sea of Programmable Functional Units (PFUs), each containing macrocells that provide the fundamental logic capabilities. These PFUs are interconnected by a global routing pool (GRP), ensuring efficient and predictable signal routing across the device.

A defining characteristic of this CPLD is its non-volatile, in-system programmable (ispXP) technology. This technology integrates E²CMOS cells for configuration storage with a SRAM programming layer. The key advantage is that the device instantly becomes operational upon power-up, as the configuration is stored on-chip without the need for an external boot PROM. This eliminates the system boot delay associated with SRAM-based FPGAs and enhances overall system security and reliability.

The `-5T` in its part number denotes a 5ns pin-to-pin logic delay, enabling a maximum operating frequency of over 200 MHz. This high-speed performance makes it suitable for critical timing applications such as bus interfacing and state machine control. The device features 256 macrocells, providing ample logic resources for complex designs.

The `TN100C` suffix specifies the package: a 100-pin Thin Quad Flat Pack (TQFP). This surface-mount package offers a compact footprint, making it ideal for space-constrained PCB designs.

In-System Programmability and Debugging

A major strength of the LC4256V is its advanced programmability. It supports IEEE 1149.1 (JTAG) boundary-scan testing, which is invaluable for board-level testing and debugging. Furthermore, through the JTAG port, designers can perform in-system programming (ISP). This allows for rapid design iterations and field firmware upgrades without removing the chip from the circuit board, drastically reducing development time and cost.

Target Applications

The combination of instant-on capability, high speed, and medium density makes the LC4256V-5TN100C a perfect fit for numerous applications, including:

System Configuration and Control: Managing power-up sequencing and reset logic for FPGAs and processors.

Bus Interface and Bridging: Acting as a glue logic interface between components with different voltage levels or protocols (e.g., PCI to local bus).

Data Communication and Processing: Implementing UARTs, SPI, I²C controllers, and small state machines.

Portable and Power-Sensitive Devices: Its low-power consumption is beneficial for battery-operated equipment.

Conclusion

The Lattice LC4256V-5TN100C stands as a highly capable and versatile CPLD. Its non-volatile ispXP technology ensures instant-on operation and design security, while its high-speed performance and 256-macrocell capacity provide the necessary resources for complex logic tasks. Packaged in a space-efficient 100-pin TQFP, it remains a compelling choice for designers seeking a reliable, fast, and reprogrammable logic solution for control and interfacing applications across various industries.

ICGOODFIND: The Lattice LC4256V-5TN100C is a high-performance, non-volatile CPLD offering instant-on capability, 200MHz+ speed, and 256 macrocells in a compact 100-pin TQFP package, making it an ideal solution for system control, interface bridging, and power-sensitive designs.

Keywords: CPLD, Non-Volatile, In-System Programmable (ISP), JTAG, Glue Logic