Lattice LC4064V-5TN100C: A Comprehensive Technical Overview of the CPLD

The Lattice LC4064V-5TN100C represents a classic and highly capable implementation of a Complex Programmable Logic Device (CPLD) from Lattice Semiconductor's high-performance ispMACH 4000V family. Designed for a wide array of general-purpose logic integration applications, this device combines a proven architecture with a robust feature set, making it a enduring choice for glue logic, bus interfacing, and control functions in complex digital systems.

Architectural Foundation: The CPLD Core

At the heart of the LC4064V lies the traditional CPLD architecture, centered around a programmable interconnect matrix that links multiple logic blocks. This deterministic, fast-connect structure is the key differentiator from FPGAs, providing the CPLD with its signature advantage: predictable, pin-to-pin timing. This makes it ideal for applications requiring critical control paths where signal delay must be consistent and guaranteed.

The device features 64 macrocells, which are grouped into four Function Blocks of 16 macrocells each. Each macrocell can be configured for combinatorial or registered logic operations, providing design flexibility. The logic is built upon a 5-nanosecond maximum pin-to-pin delay, enabling high-speed operation for its class.

In-System Programmability (ISP) and Debugging

A defining feature of this family is its advanced In-System Programmability (ISP). Utilizing the industry-standard IEEE 1149.1 (JTAG) interface, the LC4064V can be programmed, reprogrammed, and tested while already soldered onto the final printed circuit board (PCB). This drastically simplifies the manufacturing process, allows for field upgrades, and enables rapid design iterations. Furthermore, the JTAG port facilitates sophisticated boundary-scan testing, allowing designers to test pin connectivity and identify potential board-level assembly issues post-deployment.

Key Specifications and Packaging

Logic Density: 64 Macrocells (~1,000 usable gates).

Speed: -5 speed grade denotes a 5.0ns maximum propagation delay (tPD).

I/O Count: The TN100C package is a 100-pin Thin Quad Flat Pack (TQFP) offering up to 64 user-defined I/O pins.

Voltage Operation: The 'V' in its name signifies a 3.3V core voltage with 5.0V tolerant I/Os, allowing it to seamlessly interface with both 3.3V and 5.0V logic devices, a crucial feature during the industry's transition to lower voltages.

Power Management: The device supports a programmable low-power mode, helping to reduce static power consumption in sensitive applications.

Target Applications

The combination of predictable timing, sufficient logic density, and versatile I/O makes the LC4064V-5TN100C suitable for a broad range of applications, including:

Address decoding and bus interfacing in microprocessor and microcontroller systems.

System glue logic integration, replacing multiple simple PALs and discrete logic ICs.

Data routing and multiplexing.

State machine control and protocol-specific control logic.

Simple DSP data path control.

Conclusion and Design Considerations

The Lattice LC4064V-5TN100C stands as a testament to the enduring utility of the CPLD architecture. While FPGAs offer vastly higher logic capacity, the CPLD's strengths in instant-on operation, design security, and deterministic timing ensure its continued relevance. For designers needing to consolidate logic, manage interface translation, or implement control functions with minimal timing uncertainty, this device remains a powerful and reliable solution. Its ISP capability future-proofs designs, allowing for easy bug fixes and feature enhancements without hardware rework.

ICGOODFIND: The Lattice LC4064V-5TN100C is a high-performance, 3.3V CPLD featuring 64 macrocells and 64 I/Os in a 100-pin TQFP package. It is renowned for its predictable 5ns pin-to-pin timing, advanced in-system programmability via JTAG, and 5V tolerant I/Os, making it an ideal choice for logic consolidation, interface bridging, and control-oriented applications in both industrial and communication systems.

Keywords:

1. CPLD (Complex Programmable Logic Device)

2. In-System Programmability (ISP)

3. Predictable Timing

4. 3.3V Core Voltage

5. JTAG Boundary-Scan