74F779PC

Overview

The onsemi 74F779PC is an 8-bit bidirectional binary counter featuring multiplexed 3-STATE I/O ports, housed in a 16-lead Plastic Dual-In-Line (PDIP) package. It operates within a supply voltage range of +4.5V to +5.5V and supports a maximum clock frequency of 105 MHz at +25°C. The device utilizes two mode pins for control functions including hold, count up, count down, and synchronous load. Propagation delays from the clock to outputs range from 3.0 ns to 11.0 ns depending on conditions.

Feature Summary

• Multiplexed 3-STATE I/O ports enable bus-oriented applications by allowing data inputs and flip-flop outputs to share the same physical lines.
• Built-in lookahead carry capability facilitates easy cascading of multiple counters without external logic gates.
• Fully synchronous operation ensures all state changes are initiated by the rising edge of the clock signal.

Applications

• Bus-oriented digital systems requiring bidirectional data counting
• Cascaded counter configurations utilizing built-in lookahead carry
• Synchronous digital logic circuits operating with standard TTL-compatible voltages

Procurement Notes

Verify component authenticity through authorized distributors or direct manufacturer channels. Confirm RoHS compliance status as indicated in official documentation. Check for obsolescence notices or lifecycle changes prior to procurement. Ensure packaging specifications match design requirements. Validate electrical characteristics against current datasheet revisions.

Selection Notes

Select this component for designs requiring fully synchronous 8-bit counting with shared I/O lines. Consider the PDIP package for through-hole mounting needs. Evaluate power supply constraints against the specified 4.5V to 5.5V operating range. Assess timing requirements against the documented propagation delay specifications. Verify thermal management capabilities for the intended ambient temperature range.

Part Context

This part belongs to the 74F series of high-speed Schottky TTL logic devices. It serves as a specialized counter IC designed for applications demanding fast switching speeds and flexible I/O configurations. The device integrates multiple control functions into a single package to reduce board space and complexity.

Replacement Considerations

Check for equivalent parts from other manufacturers offering identical pinouts and electrical characteristics. Verify package compatibility if substituting with surface mount variants. Ensure functional equivalence regarding control logic and output states. Review updated datasheets for any specification changes in potential replacements.

FAQ

How are the control functions managed?

All control functions such as hold, count up, count down, and synchronous load are controlled by two mode pins, S0 and S1.

What initiates state changes in the counter?

All state changes are initiated by the rising edge of the clock signal.

Does the device support cascading?

Yes, the device features built-in lookahead carry capability to facilitate easy cascading.