The 74HC/HCT299 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL).
The Philips 74HC/HCT299 is a high-speed Si-gate CMOS device containing eight edge-triggered D-type flip-flops. It is pin compatible with low power Schottky TTL (LSTTL) and is specified in compliance with JEDEC standard no. 7A. The device features multiplexed inputs/outputs that provide improved bit density and can be cascaded for n-bit word lengths.
The component supports four operating modes: shift left, shift right, hold (store), and load data. It operates with output enable or at a high-impedance OFF-state (Z), allowing 3-state outputs to drive bus lines directly. The device includes asynchronous master reset and 3-state output enable inputs to control data flow and bus interfacing.
| Number of Flip-Flops | Eight |
|---|---|
| Operating Modes | shift left, shift right, hold, load data |
| Output Capability | bus driver (parallel I/Os), standard (serial outputs) |
| Maximum Clock Frequency (74HC) | 50 MHz |
| Input Capacitance | 35 pF |
| Output Capacitance | 10 pF |
| Power Dissipation Capacitance (74HC) | 120 pF |
| Propagation Delay (74HC) | 20 ns |
| Propagation Delay (74HCT) | 24 ns |
The four operating modes are shift left, shift right, hold (store), and load data.
Yes, the device is pin compatible with low power Schottky TTL (LSTTL).
A LOW signal on the asynchronous master reset input (MR) overrides the S, and clock (CP) inputs and resets the flip-flops.
A HIGH signal on the 3-state output enable inputs disables the 3-state buffers and sets the I/O outputs to the high-impedance OFF-state.