MC74AC259DG ON Semiconductor

MC74AC259, MC74ACT259 8-Bit Addressable Latch The MC74AC259/74ACT259 is a highspeed 8bit addressable latch designed for general purpose storage applications in digital systems. It is a multifunctional device capable of storing single line data in eight addressable latches, and also a 1of8 decoder and demultiplexer with active HIGH outputs. The device also incorporates www.onsemi.com an active LOW Common Clear for resetting all latches, as well as an active LOW Enable. It is functionally identical to the ALS259 8bit MARKING addressable latch. DIAGRAM 16 SerialtoParallel Conversion SOIC16 xxx259G Eight Bits of Storage with Output of Each Bit Available D SUFFIX 16 AWLYWW Random (Addressable) Data Entry CASE 751B 1 1 Active High Demultiplexing or Decoding Capability Easily Expandable xxx = AC or ACT Common Clear A = Assembly Location WL = Wafer Lot These are PbFree Devices Y = Year V MR E DQ Q Q Q WW = Work Week CC 7 6 5 4 G = PbFree Package 16 15 14 13 12 11 10 9 ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 8 of this data sheet. 1 2 3 4 567 8 A A A Q Q Q Q GND 0 1 2 0 1 2 3 Figure 1. Pinout: 16Lead Packages Conductors (Top View) ED A 0 A 1 A 2 MR Q Q Q Q Q Q Q Q 0 1 2 3 4 5 6 7 Figure 2. Logic Symbol MODE SELECT TABLE E MR Mode L H Addressable Latch H H Memory L L Active HIGH 8Channel Demultiplexer H L Clear H = HIGH Voltage Level L = LOW Voltage Level Semiconductor Components Industries, LLC, 2015 1 Publication Order Number: March, 2015 Rev. 7 MC74AC259/DMC74AC259, MC74ACT259 MODE SELECTFUNCTION TABLE Inputs Outputs Operating Mode MR E D A A A Q Q Q Q Q Q Q Q 0 1 2 0 1 2 3 4 5 6 7 Master Reset L H X X X X L L L L L L L L L L d L L L Q = d L L L L L L L L Ld H L L L Q = d LLLLLL Demultiplex L Ld L H L L L Q = d LLLLL (Active HIGH Decoder when D = H) L Ld H H H L L LLLLL Q = d Store H H X X X X q q q q q q q q 0 1 2 3 4 5 6 7 (Do Nothing) H L d L L L Q = d q q q q q q q 1 2 3 4 5 6 7 H Ld H L L q Q = d q q q q q q 0 2 3 4 5 6 7 H Ld L H L q q Q = d q q q q q 0 1 3 4 5 6 7 Addressable Latch H L d H H H q q q q q q q Q = d 0 1 2 3 4 5 6 H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial d = HIGH or LOW Data one setup time prior to the LOWtoHIGH Enable transition q = Lower case letters indicate the state of the referenced output established during the last cycle in which it was addressed or cleared. FUNCTIONAL DESCRIPTION In the oneofeight decoding or demultiplexing mode, the addressed output will follow the state of the D input with all The MC74AC259/74ACT259 has four modes of other outputs in the LOW state. In the clear mode all outputs operation as shown in the Mode Selection Table. In the are LOW and unaffected by the address and data inputs. addressable latch mode, data on the Data line (D) is written When operating the MC74AC/ACT259 as an addressable into the addressed latch. The addressed latch will follow the latch, changing more than one bit of the address could data input with all nonaddressed latches remaining in their impose a transient wrong address. Therefore, this should previous states in the memory mode. All latches remain in only be done while in the memory mode. The Mode Select their previous state and are unaffected by the Data or Function Table summarizes the operations of the Address inputs. MC74AC/ACT259. www.onsemi.com 2