Lattice ISPLSI2128VE-100LTN176: A Comprehensive Technical Overview of the High-Density CPLD

In the realm of digital logic design, Complex Programmable Logic Devices (CPLDs) serve as a critical bridge between simple PLDs and high-capacity FPGAs. The Lattice Semiconductor ISPLSI2128VE-100LTN176 stands as a prominent example of a high-density, in-system programmable CPLD engineered for complex, glue-logic applications. This article provides a detailed technical examination of this specific device, its architecture, key features, and target applications.

At its core, the ISPLSI2128VE is built upon Lattice's advanced High-Density SuperFAST® ispLSI 2000VE Architecture. This nomenclature breaks down as follows: "2128" indicates it contains 128 macrocells, "VE" signifies the product family, "100" specifies a maximum operating frequency of 100 MHz, and "LTN176" denotes the 176-pin TQFP (Thin Quad Flat Pack) package. This architecture is organized into a Generic Logic Block (GLB) structure, where multiple GLBs are interconnected via a Global Routing Pool (GRP). This GRP acts as a highly efficient, programmable central switch matrix, ensuring predictable timing and fast signal paths across the entire device—a hallmark advantage of CPLDs over FPGAs for certain applications.

The device's programmability is a key strength. It leverages an electrically erasable (E²) CMOS technology for its non-volatile memory cells. This allows the device to be reprogrammed in-system (ISP) via a standard 5-wire JTAG (IEEE 1149.1) interface. This capability facilitates rapid design iterations, field upgrades, and easy prototyping without physically removing the chip from the circuit board.

A deep dive into its specifications reveals its performance credentials. The `-100` grade guarantees a pin-to-pin delay of just 7.5 ns, enabling its use in high-speed control and data path management systems. The 128 macrocells provide a flexible logic resource, each capable of being configured for wide combinational or registered functions. Furthermore, the device features 5V in-system programmability (ISP) and 3.3V operation, making it ideal for mixed-voltage systems and offering robust noise immunity.

The 176-pin package offers a substantial number of user I/O pins, which are grouped into I/O cells connected to an Output Routing Pool (ORP). This structure provides flexibility in pin assignment and supports various interface standards. Additional features include programmable bus hold and pull-up resistors on all I/Os, further enhancing design integration and signal integrity.

The combination of high speed, deterministic timing, and non-volatile programmability makes the ISPLSI2128VE-100LTN176 perfectly suited for a wide array of applications. It is commonly deployed for address decoding, bus interfacing (e.g., PCI local bus control), state machine implementation, and high-speed register banking. It is also extensively used in telecommunications equipment, computer peripherals, and industrial control systems to integrate numerous discrete logic devices into a single, compact, and reliable chip.

ICGOOODFIND: The Lattice ispLSI2128VE-100LTN176 remains a robust and reliable high-density CPLD solution. Its non-volatile nature, SuperFAST predictable timing, and 5V in-system programmability offer a distinct set of advantages for designers managing complex state machines and interface logic in embedded systems, ensuring stable operation and simplified development cycles.

Keywords: High-Density CPLD, In-System Programmability (ISP), Non-Volatile, Deterministic Timing, Generic Logic Block (GLB)