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the commercial market, introduced by Monolithic Memories, Inc. (MMI). The PAL,
in comparison to the PLA has a fixed set of OR gates, and thus a fixed number of
programmable AND planes. However, the PAL allows reuse of function outputs, and
can be then used in another PAL program block. Early PALs were 20-pin DIP (dual
inline package) components fabricated in bipolar silicon transistor technology with
nichrome programming fuses. The 16L8 and 16R8 were popular members of the
product family. The devices have fixed-or, programmable-and-plane arrays of
transistor cells to implement 'sum-of-products' binary logic equations for each of the
outputs in terms of the inputs and either synchronous or asynchronous feedback from
the outputs. Before PALs were introduced digital designers would use SSI (small-
scale integration) components, such as 7400 series nand gates and D-flipflops. One
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