SN74LS600A

The SN74LS600A memroy refresh controller contains one 8-bit synchronous counter, nine 3-state buffer drivers, four RC-controlled multivibrators, and other control circuitry on a single monolithic chip.It is designed to provide RAS-only refresh on 4K dynamic RAMs.It provides transparent refresh.

Features of of the SN74LS600A are:(1)controls refresh cycle of 4K dynamic RAMs; (2)creates static RAM appearance; (3)choice of transparent, cycle steal, or burst refresh modes; (4)3-state outputs drive bus lines directly; (5)critical times are user RC-programmable to optimize system performance.

The absolute maximum ratings of the SN74LS600A can be summarized as:(1): supply voltage, vcc is 7 V; (2): input voltage range, Vi is 7 V; (3): operating free-air temperature, Ta is 0 to 70; (4): storage temperature range is -65 to 150.