TC74HC191AF(F) Toshiba

TC74HC191AP/AF TOSHIBA CMOS Digital Integrated Circuit Silicon Monolithic TC74HC191AP, TC74HC191AF 4-Bit Binary Up/Down Counter The TC74HC191A are high speed CMOS 4-BIT UP/DOWN 2 TC74HC191AP COUNTERs fabricated with silicon gate C MOS technology. It achieves the high speed operation similar to equivalent LSTTL while maintaining the CMOS low power dissipation. The TC74HC191A is 4-bit binary up/down counter. They have an asynchronous load input ( LOAD ) which is active low. The direction of counting is determined by the level of DOWN/UP. When D/U is low, the counter counts up when D/U is high, it counts down. Counting occurs on the positive going transition of the clock input. TC74HC191AF Enable input ( ENABLE ) and two carry inputs (RIPPLE CLOCK OUT, MAX/MIN) are provided to permit easy cascading of the counters, which facilitates easy implementation of N-bit counters without using external gates. All inputs are equipped with protection circuits against static discharge or transient excess voltage. Features High speed: fmax = 48 MHz (typ.) at V = 5 V CC Weight Low power dissipation: I = 4 A (max) at Ta = 25C DIP16-P-300-2.54A : 1.00 g (typ.) CC SOP16-P-300-1.27A : 0.18 g (typ.) High noise immunity: V = V = 28% V (min) NIH NIL CC Output drive capability: 10 LSTTL loads Symmetrical output impedance: I = I = 4 mA (min) OH OL Balanced propagation delays: t t pLH pHL Wide operating voltage range: V (opr) = 2 to 6 V CC Pin and function compatible with 74LS191 Pin Assignment Start of commercial production 1988-11 1 2014-03-01 TC74HC191AP/AF IEC Logic Symbol Truth Table Inputs Outputs Function LOAD ENABLE D/U CK QA QB QC QD L X X X a b c d Preset Data H L L Up Count Up Count H L H Down Count Down Count H H X No Change No Count H X X No Change No Count X: Dont care a to d: Inputs level of A to D 2 2014-03-01