PAL20R4ACNS

The PAL20R8 Family (PAL20L8, PAL20R8, PAL20R6, PAL20R4) includes the PAL20R8-5 Series which is ideal for high-performance applications. The PAL20R8 Family is provided in the standard 24-pin DIP and 28-pin PLCC pinouts. The devices provide user programmable logic for re-placing conventional SSI/LSI gates and flip-flops at a re-duced chip cost. The family allows the systems engineer to implement the design on-chip, by opening fuse links to configure AND and OR gates within the device, according to the desired logic function. Complex interconnections be-tween gates, which previously required time-consuming layout, are lifted from the PC board and placed on sili-con, where they can be easily modified during prototyp-ing or production. The PAL device implements the familiar Boolean logic transfer function, the sum of products. The PAL device is a programmable AND array driving a fixed OR array. The AND array is programmed to create custom product terms, while the OR array sums selected terms at the outputs. In addition, the PAL device provides the following options: — Variable input/output pin ratio — Programmable three-state outputs — Registers with feedback Product terms with all connections opened assume the logical HIGH state; product terms connected to both true and complement of any single input assume the logical LOW state. Registers consist of D-type flip-flops that are loaded on the LOW-to-HIGH transition of the clock. Unused input pins should be tied to Vcc or GND. AMD’s FusionPLD program allows PAL20R8 Family de-signs to be implemented using a wide variety of popular industry-standard design tools. By working closely with the FusionPLD partners, AMD certifies that the tools provide accurate, quality support. By ensuring that third-party tools are available, costs are lowered because a designer does not have to buy a complete set of new tools for each device. The FusionPLD program also greatly reduces design time since a designer can use a tool that is already installed and familiar. Please refer to the PLD Software Reference Guide for certified devel-opment systems and the Programmer Reference Guide for approved programmers.