SN74LS490

The SN74LS490 is designed as dual decade counter which would be low power schottky type. It contains a pair of high-speed 4-stage ripple counters. Each half of this device has individual clock, master reset and master set (preset 9) inputs. Each section counts in the 8, 4, 2, 1 BCD code.

SN74LS490 has four features. (1)Dual version. (2)Individual asynchronous clear and preset to 9 for each counter. (3)Count frequency-typically 65MHz. (4)Input clamp diodes limit high-speed termination effects. Those are all the main features.

Some guaranteed operating ranges of SN74LS490 have been concluded into several points as follow. (1)Its supply voltage range would be min 4.75V and typ 5.0V and max 5.25V. (2)Its operating ambient temperature range would be min 0°C and typ 25°C and max 70°C. (3)Its output current high level would be max -0.4mA. (4)Its output current low level would be max 8mA.

Also some DC characteristics of SN74LS490 are concluded as follow. (1)Its input high voltage would be min 2.0V with conditions of guaranteed input high voltage for all inputs. (2)Its input low voltage would be max 0.8V with conditions of guaranteed input low voltage for all inputs. (3)Its input clamp diode voltage would be typ -0.65V and max -1.5V with condition of Vcc=min, Iin=-18mA. (4)Its output high voltage would be min 2.7V and typ 3.5V with condition of Vcc=min and Ioh is max and input voltage is high level or low level per truth table. (5)Its output low voltage would be typ 0.25V and max 0.4V with condition of Iol=max. (6)Its input high current would be max 20uA with condition of Vcc=max and Vin=2.7V and would be max 0.1mA with conditions of Vcc=max, Vin=7.0V. (7)Its input low current would be max -0.4mA with condition of Vcc=max and input voltage is 0.4V. (8)Its power supply current would be max 26mA with condition of Vcc=max. (9)Its short circuit current would be min -20mA and max -100mA.

And some AC characteristics of SN74LS490 are concluded into several points as follow. (1)Its any pulse width would be min 20ns. (2)Its MR or MS to setup time would be min 25ns. (3)Its maximum clock frequency would be min 25MHz and typ 35MHz. And so on. If you have any question or suggestion or want to know more information please contact us for details. Thank you!