MAX 3000A Programmable Logic Device Family Data Sheet
Expander Product Terms
Although most logic functions can be implemented with the five product
terms available in each macrocell, highly complex logic functions require
additional product terms. Another macrocell can be used to supply the
required logic resources. However, the MAX 3000A architecture also
offers both shareable and parallel expander product terms (“expanders”)
that provide additional product terms directly to any macrocell in the
same LAB. These expanders help ensure that logic is synthesized with the
fewest possible logic resources to obtain the fastest possible speed.
Shareable Expanders
Each LAB has 16 shareable expanders that can be viewed as a pool of
uncommitted single product terms (one from each macrocell) with
inverted outputs that feed back into the logic array. Each shareable
expander can be used and shared by any or all macrocells in the LAB to
build complex logic functions. Shareable expanders incur a small delay
(tSEXP). Figure 3 shows how shareable expanders can feed multiple
macrocells.
Figure 3. MAX 3000A Shareable Expanders
Shareable expanders can be shared by any or all macrocells in an LAB.
Macrocell
Product-Term
Logic
Product-Term Select Matrix
Macrocell
Product-Term
Logic
36 Signals
from PIA
16 Shared
Expanders
8
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