Lattice GAL16V8D-10LPN: Architecture, Key Features, and Application Design Considerations
The Lattice GAL16V8D-10LPN stands as a quintessential example of a high-performance, low-power programmable logic device (PLD) from the Generic Array Logic (GAL) family. As a 20-pin CMOS-based device, it offers designers a flexible and reliable solution for integrating complex combinatorial and sequential logic, serving as a glue logic component, state machine controller, and address decoder in countless digital systems.
Architectural Overview
At its core, the GAL16V8D-10LPN architecture is built around a programmable AND array feeding into a fixed OR array. This structure efficiently implements sum-of-products logic functions. The device features eight configurable output logic macrocells (OLMCs), which provide immense flexibility for output configuration. Each macrocell can be programmed to be combinatorial or registered, with options for active-high or active-low operation and programmable feedback into the AND array. This allows a single device to replace multiple simple fixed-function ICs. The "16" in its name denotes the number of inputs, while the "8" represents the maximum number of outputs.
Key Features and Specifications
The GAL16V8D-10LPN is defined by a set of characteristics that make it particularly suitable for modern, power-sensitive designs.
High-Speed Operation: The `-10` suffix indicates a maximum propagation delay (`t_{PD}`) of 10 nanoseconds, enabling operation at high clock frequencies.
Low Power Consumption: Fabricated in advanced CMOS technology, it consumes significantly less power than its bipolar (e.g., PAL) predecessors, making it ideal for battery-operated or power-conscious applications.
Electrically Erasable: The device utilizes EE CMOS technology for the programmable fuse array. This allows it to be reprogrammed and erased electrically, facilitating rapid design iteration and prototyping without requiring UV erasure.
100% Testability: The internal architecture supports functional testability, ensuring that the programmed device can be thoroughly verified.
High Output Drive: The outputs offer strong drive capability, capable of sourcing 24 mA and sinking 48 mA, allowing them to directly interface with other components like LEDs or bus transceivers without needing buffer chips.
Application Design Considerations
Successfully implementing the GAL16V8D-10LPN requires careful attention to several design aspects:
1. Power-On Reset: The device features a power-on reset circuit that ensures all registers initialize to a known state (typically low) upon application of power. Designers must verify that this initial state is safe for their system.
2. Programming and Security: The device is programmed using a standard JEDEC file generated by HDL compilers or logic minimizers. A programmable security fuse is available to prevent unauthorized copying of the programmed bitstream, protecting intellectual property.
3. Signal Integrity: While the outputs have high drive strength, designers must be cautious of transient power supply currents caused when multiple outputs switch simultaneously. Proper decoupling with 0.1 µF capacitors close to the Vcc and GND pins is essential to suppress noise.
4. Thermal Management: Although a low-power device, the total power dissipation (calculated as `I_{CC} V_{CC}` plus the sum of the output power) must be checked to ensure the package remains within its safe operating temperature.
5. Design for Test (DFT): The programmable nature of the device allows for the incorporation of test logic. Designers should consider adding circuitry to make internal states observable, easing system-level debugging and testing.
The Lattice GAL16V8D-10LPN remains a highly effective and economical solution for a vast array of digital logic consolidation tasks. Its blend of high speed, reprogrammability, and low power consumption ensures its continued relevance in modern electronic design, from industrial control systems to consumer electronics, where reliability and design flexibility are paramount.
Keywords: Programmable Logic Device (PLD), Output Logic Macrocell (OLMC), EE CMOS Technology, Low-Power Design, JEDEC File.
