DM74LS491N ,10-Bit CounterDM54LS491/74LS49110-BitCounterJuly1989DM54LS491/74LS49110-BitCounterGeneralDescription
DM74LS51N ,Dual 2-Wide 2-Input, 2-Wide 3-Input AND-OR-INVERT GateGeneral DescriptionThis device contains two independent combinations ofgates each of which performs ..
DM74LS534N ,Octal D-Type Flip-Flop with 3-STATE OutputsFunctional DescriptionThe DM74LS534 consists of eight edge-triggered flip-flops sistion. With the O ..
DM74LS54N ,4-WIDE, 2-INPUT AND-OR-INVERT GATEGeneral Description
This device contains a combination of four, two input AND
gates whose outpu ..
DM74LS55N ,2-Wide, 4-Input AND-OR-INVERT GateDM54LS55/DM74LS552-Wide,4-InputAND-OR-INVERTGateApril1992DM54LS55/DM74LS552-Wide,4-InputAND-OR-INVE ..
DM74LS573N ,Octal D-Type Latch with 3-STATE OutputsFeaturesThe DM74LS573 is a high speed octal latch with buffered Inputs and outputs on opposite sid ..
DS2411R+T&R ,Silicon Serial Number with VCC InputPIN DESCRIPTION *The DS2411X is RoHS qualified and comes in tape and reel. PIN NAME FLIP SOT23 ..
DS2411R+U ,Silicon Serial Number with VCC Input19-6131; Rev 11/11 DS2411 Silicon Serial Number with V InputCC
DS2411R-107-01+T ,Silicon Serial Number with VCC InputPIN DESCRIPTION *The DS2411X is RoHS qualified and comes in tape and reel. PIN NAME FLIP SOT23 ..
DS2411R-221-30C+T ,Silicon Serial Number with VCC InputFEATURES PIN CONFIGURATION Unique, Factory-Lasered and Tested 64-Bit 3 Registration Number (8-B ..
DS2411X ,Silicon Serial Number with VCC InputFEATURES PIN CONFIGURATION Unique, Factory-Lasered and Tested 64-Bit3Registration Number (8-Bit Fa ..
DS2413 ,1-Wire Dual Channel Addressable SwitchAPPLICATIONS 1-Wire IO Pin Supports 28V Absolute Maximum LED Control DC Level for Fault Condi ..
DM74LS491N
10-Bit Counter
TL/L/8332
DM54LS491/74LS491
10-Bit
Counter
July 1989
DM54LS491/74LS491 10-Bit Counter
General Description
The ten-bit countercan countup, count down, set,and load LSB’s,2 MSB’sand6 middlebits highorlowasa group.
All operationsare synchronous withthe clock. SET over-
rides LOAD, COUNTand HOLD. LOAD overrides COUNT.
COUNTis conditionalon CIN, otherwiseit holds.
All outputsare enabled whenOEislow, otherwise HIGH-Z.
The24mAIOL outputsare suitablefor driving RAM/PROM
address linesin video graphics systems.
Features/Benefits CRT verticaland horizontal timing generation Bus-structured pinout 24-pin SKINNYDIP saves space TRI-STATEÉ outputs drivebus lines Low current PNP inputs reduce loading
Connection Diagram
Top View
TL/L/8332–1
Order Number DM54LS491J,
DM74LS491Jor DM74LS491N
See NSPackageNumber J24For N24C
Standard Test Load
TL/L/8332–2
Function TableCK SET LDCNTCINUP D9-D0 Q9-Q0 OperationXXXX XX X Z Hi-ZuHXX XX X H Set allHIGHuLLX XX D D LOADDuLHH XX X Q HOLDuLHL HX X Q HOLDuLHLLL X Q plus1 CountUPuLHLLH X Qminus1 CountDN
TRI-STATEÉ isaregistered trademarkof National SemiconductorCorp.
C1995National SemiconductorCorporation RRD-B30M115/PrintedinU.S.A.
