The TC74VHC393 is an advanced high speed CMOS 4-BIT BINARY
COUNTER fabricated with silicon gate C2MOS technology.
It achieves the high speed operation similar to equivalent Bipolar Schottky
TTL while maintaining the CMOS low power dissipation.
It contains two independent counter circuits in one package, so that
counting or frequency division of eight binary bits can be achieved with one
IC.
This device changes state on the negative going transition of the CLOCK
pulse. The counter can be reset to “0” (QA to QD = “L”) by a high at the
CLEAR input regardless of other inputs.
An input protection circuit ensures that 0 to 5.5 V can be applied to the
input pins without regard to the supply voltage. This device can be used to
interface 5 V to 3 V systems and two supply systems such as battery back
up. This circuit prevents device destruction due to mismatched supply and
input voltages.

Features
 High speed: fmax = 170 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)
 Power down protection is provided on all inputs.
 Balanced propagation delays: tpLH ∼− tpHL
 Wide operating voltage range: VCC (opr) = 2 to 5.5 V
 Low noise: VOLP = 0.8 V (max)
 Pin and function compatible with 74ALS393