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
COUNTERs fabricated with silicon gate C2MOS 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.
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.
TC74HC191AP
TC74HC191AF
Features
•
High speed: fmax = 48 MHz (typ.) at VCC = 5 V
•
Low power dissipation: ICC = 4 μA (max) at Ta = 25°C
•
High noise immunity: VNIH = VNIL = 28% VCC (min)
•
Output drive capability: 10 LSTTL loads
•
•
Symmetrical output impedance: |IOH| = IOL = 4 mA (min)
∼
Balanced propagation delays: tpLH − tpHL
•
Wide operating voltage range: VCC (opr) = 2 to 6 V
•
Pin and function compatible with 74LS191
Weight
DIP16-P-300-2.54A
SOP16-P-300-1.27A
: 1.00 g (typ.)
: 0.18 g (typ.)
Pin Assignment
1
2009-09-01
