CD74HC297E

Overview

The CD74HC297E is a high-speed Si-gate CMOS digital phase-locked-loop filter manufactured by Harris Corporation. It is pin-compatible with low power Schottky TTL (LSTTL) and complies with JEDEC standard no. 7A. The device integrates circuits for first-order phase-locked-loops, excluding the divide-by-n counter. It operates within a supply voltage range of 2 V to 6 V. The package is a 14-pin Plastic Dual In-Line Package (PDIP).

Feature Summary

• Digital design eliminates analog compensation errors.
• Supports dynamic bandwidth variation.
• Includes power-on reset functionality.

Applications

• First-order digital phase-locked-loop construction.
• High-accuracy digital PLL applications.
• Frequency synthesis systems requiring narrow bandwidth.

Procurement Notes

Verify the manufacturer designation as Harris Corporation on the component marking. Confirm the package type is PDIP-14. Check for RoHS compliance status, as older Harris batches may not meet current environmental standards. Ensure the suffix 'E' corresponds to the specified plastic DIP package variant.

Selection Notes

Select this component when a digital solution for phase-locked loops is required to avoid analog tuning issues. It serves as a direct replacement for similar HCT/HC series devices in LSTTL-compatible designs. Verify that the operating frequency requirements fall within the typical ranges of 55 MHz for K-clock and 35 MHz for I/D-clock inputs.

Part Context

This part belongs to the 74HC/HCT logic family, designed for high-speed CMOS applications. It is functionally equivalent to other manufacturers' 74HC297 parts but carries the Harris branding. The device is categorized under MSI (Medium Scale Integration) logic circuits.

Replacement Considerations

Compatible substitutes include the NXP HEF40HC297 or Texas Instruments SN74HC297. Verify pin compatibility and electrical specifications before substitution. Ensure the alternative part supports the same 2V to 6V supply range and PDIP-14 package.

FAQ

What is the primary function of the CD74HC297E?

It functions as a digital phase-locked-loop filter, providing necessary circuits for first-order PLLs except for the divide-by-n counter.

Is the CD74HC297E compatible with LSTTL?

Yes, it is pin-compatible with low power Schottky TTL (LSTTL).

What are the typical frequency ranges for the K-clock and I/D-clock?

The typical useful frequency range is DC to 55 MHz for the K-clock and DC to 35 MHz for the I/D-clock.