74F579SJ

Overview

The onsemi 74F579SJ is an 8-bit bidirectional binary counter featuring multiplexed 3-STATE I/O ports. It operates within a supply voltage range of +4.5V to +5.5V and supports a typical count frequency of 100 MHz. The device utilizes a 20-Lead Small Outline Package (SOP) with a width of 5.3mm. Key electrical parameters include a maximum clock frequency of 80 MHz at the upper temperature limit, propagation delays ranging from 3.0 ns to 13.5 ns depending on the signal path, and guaranteed ESD protection of 4000V minimum.

Feature Summary

• Multiplexed 3-STATE I/O ports for bus-oriented applications
• Built-in lookahead carry capability for easy cascading
• Fully synchronous 8-stage up/down counting initiated by rising clock edge
• Preset capability for programmable parallel loading operations

Applications

• Bus-oriented data storage and transfer systems
• Cascaded multi-stage digital counting circuits
• Programmable timing and sequence control logic
• Bidirectional data flow management in digital interfaces

Procurement Notes

Verify component authenticity through official manufacturer channels or authorized distributors. Confirm package marking matches the M20D designation for the 20-Lead SOP variant. Check RoHS compliance status as manufacturing processes may evolve. Ensure storage conditions adhere to moisture sensitivity levels specified in the datasheet to prevent package damage prior to assembly.

Selection Notes

Select this component when designing systems requiring high-speed bidirectional counting with integrated output tri-stating capabilities. The built-in lookahead carry simplifies the design of wider counters without external logic gates. Verify that the operating voltage aligns with the +4.5V to +5.5V specification. Consider the thermal dissipation requirements given the typical supply current of 75 mA during active operation.

Part Context

This part belongs to the 74F series of high-speed TTL-compatible logic devices. It serves as a specialized counter alternative to standard flip-flop arrays, integrating direction control and parallel load functions into a single package. The SJ suffix specifically denotes the 20-Lead Small Outline Package (SOP) form factor, distinguishing it from SOIC or PDIP variants within the same logical family.

Replacement Considerations

Direct pin-to-pin replacements must maintain 8-bit bidirectional counting and 3-STATE output compatibility. Verify that substitute components support the same +4.5V to +5.5V supply range and meet the required 100 MHz typical count frequency specifications. Ensure the replacement package matches the 20-Lead SOP dimensions for mechanical fit.