Lattice LC4064V-75TN44C: A Comprehensive Technical Overview of the CPLD

The Lattice LC4064V-75TN44C represents a classic and highly capable implementation of a Complex Programmable Logic Device (CPLD) from Lattice Semiconductor. As a member of the mature ispMACH 4000V family, this device is engineered to provide a balanced mix of density, performance, and power efficiency, making it a enduring choice for a wide array of control-oriented logic applications.

Architectural Foundation: The CPLD Core

At the heart of the LC4064V lies the fundamental CPLD architecture, centered around a programmable interconnect matrix that links multiple logic blocks. This specific device features 64 macrocells, a key metric defining its capacity. These macrocells are grouped into Function Blocks, each containing 16 macrocells. This structure provides a predictable, deterministic timing model, which is a significant advantage over FPGAs for glue logic and state machine control where pin-to-pin timing consistency is critical.

Each macrocell can be configured for registered or combinatorial operation, supporting a variety of clocking modes. The device offers global clocking resources with high drive strength to ensure synchronous performance across the entire chip.

Performance and Capabilities

The part number suffix `-75` denotes a maximum propagation delay (tPD) of 7.5 ns, enabling it to support system clock speeds well above 100 MHz. This performance level is suitable for bridging interfaces, managing bus arbitration, and implementing complex state machines without becoming a system bottleneck.

The LC4064V contains 64 I/O pins (of the 44-pin package), all of which are highly flexible. These pins support various I/O standards, most notably LVCMOS 3.3V, which was the industry standard at its peak. The I/O cells can be configured for input, output, or bidirectional operation with individual slew-rate control.

In-System Programmability (ISP)

A defining feature of this CPLD family is its advanced in-system programmability (ISP). Utilizing a standard 4-pin JTAG (IEEE 1149.1) interface, the device can be reprogrammed while soldered onto the final circuit board. This drastically simplifies the design iteration, debugging, and field upgrade processes, reducing time-to-market and overall cost.

Power Consumption and Packaging

Fabricated in a low-power process, the LC4064V-75TN44C is designed for low standby and dynamic power consumption. This makes it an attractive solution for portable and battery-operated equipment where power budgets are constrained. The device is offered in a 44-pin Thin Plastic Quad Flat Pack (TQFP) package, a compact form factor suitable for space-sensitive PCB designs.

Target Applications

The combination of medium density, high speed, and low power makes this CPLD ideal for numerous applications, including:

Address decoding and bus interfacing in microprocessor systems.

Data path control and DMA control.

System configuration and power-up sequencing for FPGAs and ASICs.

Protocol bridging (e.g., between SPI, I2C, and parallel interfaces).

Function integration to consolidate multiple simple PALs and GALs into a single, reprogrammable device.

ICGOOODFIND: The Lattice LC4064V-75TN44C CPLD stands as a robust and reliable workhorse in the world of programmable logic. Its deterministic timing, high-performance 7.5ns speed, 64-macrocell capacity, low-power operation, and critical JTAG-based in-system programmability solidify its role as a perfect solution for control logic, interface bridging, and system integration in countless electronic products.

Keywords: CPLD, In-System Programmability (ISP), Macrocell, Deterministic Timing, LVCMOS.