8-bit addressable latch
• ESD protection:
HBM EIA/JESD22-A114-A exceeds 2000 V
MM EIA/JESD22-A115-A exceeds 200 V
CDM EIA/JESD22-C101 exceeds 1000 V
• Balanced propagation delays
• All inputs have Schmitt-trigger actions
• Combines demultiplexer and 8-bit latch
• Serial-to-parallel capability
• Output from each storage bit available
• Random (addressable) data entry
• Easily expandable
• Common reset input
• Useful as a 3-to-8 active HIGH decoder
• Inputs accept voltages higher than VCC
• For AHC only: operates with CMOS input levels
• For AHCT only: operates with TTL input levels
• Specified from −40 to +85 °C and from −40 to +125 °C.
The 74AHC/AHCT259 are high-speed Si-gate CMOS
devices and are pin compatible with Low power Schottky
TTL (LSTTL). They are specified in compliance with
JEDEC standard No. 7A.
The 74AHC/AHCT259 are high-speed 8-bit addressable
latches designed for general purpose storage applications
in digital systems. The ‘259’ are multifunctional devices
capable of storing single-line data in eight addressable
latches, and also 3-to-8 decoder and demultiplexer, with
active HIGH outputs (Q0 to Q7), functions are available.
The ‘259’ also incorporates an active LOW common reset
(MR) for resetting all latches as well as an active LOW
enable input (LE).
The ‘259’ has four modes of operation as shown in the
mode select table. In the addressable latch mode, data on
the data line (D) is written into the addressed latch. The
addressed latch will follow the data input with all non-
addressed latches remaining in their previous states.
In the memory mode, all latches remain in their previous
states and are unaffected by the data or address inputs.
In the 3-to-8 decoding or demultiplexing mode, the
addressed output follows the state of the (D) input with all
other outputs in the LOW state. In the reset mode all
outputs are LOW and unaffected by the address
(A0 to A2) and data (D) input. When operating the ‘259’ as
an address latch, changing more than one bit of the
address could impose a transient-wrong address.
Therefore, this should only be done while in the memory
The mode select table summarizes the operations of
2000 Mar 14