onsemi (Ansemi)

TSSOP-16

taping

2500

MC74HC259A has the same pinout as LS259. The device inputs are compatible with standard CMOS outputs; pull-up resistors are included for compatibility with LSTTL outputs. The HC259A has four modes of operation as shown in the mode selection table. In Addressable Latch Mode, the data on the data input will be written to the addressed latch. Addressed latches carry forward the data input, and all unaddressed latches remain in their previous state. In memory mode, all latches remain in their previous state, independent of data or address inputs. In 1/8 decode or signal split mode, the addressed output follows the state of the data input, all other outputs are low state. In reset mode, all outputs are low regardless of address and data inputs. When the HC259A is operating as an addressable latch, changing multiple bits of the address may cause a transient wrong address. Therefore, such changes should be done in memory mode.