Function, Pinout, and Drive Compatible
With FCT and F Logic
Reduced VOH (Typically = 3.3 V) Versions
of Equivalent FCT Functions
Edge-Rate Control Circuitry for
Significantly Improved Noise
Characteristics
Ioff Supports Partial-Power-Down Mode
Operation
ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
– 1000-V Charged-Device Model (C101)
Matched Rise and Fall Times
64-mA Output Sink Current
32-mA Output Source Current

description
The CY74FCT191T is a reversible modulo-16 binary counter, featuring synchronous counting and
asynchronous presetting. The preset allows the CY74FCT191T to be used in programmable dividers. The count
enable input, terminal count output, and ripple-clock output make possible a variety of methods of implementing
multiusage counters. In the counting modes, state changes are initiated by the rising edge of the clock.
This device is fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs,
preventing damaging current backflow through the device when it is powered down.