Lattice GAL22LV10D-4LJ: Architecture, Key Features, and Target Applications

The Lattice GAL22LV10D-4LJ is a member of the widely adopted Generic Array Logic (GAL) family of programmable logic devices (PLDs). As a high-performance, low-power CMOS device, it serves as a versatile building block for a multitude of digital logic designs, offering a programmable alternative to fixed-function logic ICs. Its enduring popularity stems from its balance of capability, ease of use, and cost-effectiveness.

Architecture

The architecture of the GAL22LV10D-4LJ is centered around a programmable AND array feeding into a fixed OR array, a structure known as the PAL® (Programmable Array Logic) architecture. The "22V10" designation is key to understanding its structure:

22 Inputs: The device features 12 dedicated input pins and 10 configurable I/O pins, which can be configured as inputs, providing a flexible interface to other system components.

10 Output Logic Macrocell (OLMC): This is the core of its programmability. Each of the 10 outputs is driven by its own OLMC. Each macrocell can be individually configured by the user for specific output functionality, including combinatorial or registered (clocked) operation. The macrocells provide control over the output polarity (active-high or active-low) and can be set to a high-impedance state.

This architecture allows designers to implement a wide range of logic functions, from simple combinatorial gates to complex state machines, all within a single integrated circuit.

Key Features

The GAL22LV10D-4LJ is characterized by several standout features that make it suitable for modern designs:

High Performance: The `-4` in its part number signifies a maximum pin-to-pin delay of 4ns, enabling operation at high clock frequencies.

Low Power Consumption: Built on advanced CMOS technology, it features very low power dissipation, making it ideal for power-sensitive applications.

Electrically Erasable (EE) Technology: The device utilizes EECMOS cells, making it reprogrammable and highly suitable for design prototyping and iterative development. Designs can be modified and tested rapidly without discarding hardware.

100% Tested/High Reliability: Each device is 100% functionally tested and offers a high degree of design security against copying.

4LJ Package: The suffix "4LJ" denotes a 28-pin PLCC (Plastic Leaded Chip Carrier) package, which is a common and robust surface-mount package.

Target Applications

The flexibility and performance of the GAL22LV10D-4LJ have secured its place in a diverse range of applications:

Address Decoding: It is perfectly suited for generating chip-select signals in microprocessor and microcontroller-based systems.

State Machine Design: Its registered outputs allow it to efficiently implement finite state machines (FSMs) for control logic.

Bus Interface Logic: It can be used to glue together different logic families or interface between components with different voltage levels or timing requirements.

Code Conversion and I/O Expansion: It can perform simple arithmetic operations, code conversion (e.g., BCD to binary), and expand the I/O capabilities of a microcontroller.

System Integration: Its primary role is often to integrate multiple simple TTL or CMOS logic devices into a single, compact PLD, reducing board space, component count, and overall system cost and complexity.

ICGOOODFIND: The Lattice GAL22LV10D-4LJ remains a highly relevant and practical solution for digital logic integration. Its blend of high speed, low power consumption, and user-reprogrammability offers an excellent compromise between the inflexibility of standard logic and the complexity of larger FPGAs. It is an ideal choice for glue logic, control applications, and system integration in both modern and legacy electronic systems.

Keywords: Programmable Logic Device (PLD), Output Logic Macrocell (OLMC), Low Power CMOS, Reprogrammable, Glue Logic.