MC88915EI55

Clock Generators, PLLs, Frequency Synthesizers Overview

The MC88915EI55 is a low skew CMOS PLL clock driver in a 28-lead PLCC package. It locks multiple outputs to a single reference input, providing frequency multiplication and distribution for high-performance systems. The device features five Q outputs (Q0-Q4) with less than 500 ps skew, an inverted Q5 output, a 2X_Q output running at twice the Q frequency, and a Q/2 output running at half the Q frequency. Operating at VCC = 5.0 V ± 5%, it supports maximum operating frequencies of 55 MHz for the 2X_Q output and 27.5 MHz for the Q outputs. Each output provides ±36 mA drive capability.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Five Q outputs (Q0–Q4) with output-to-output skew < 500 ps
• Phase-locked frequency ratios of 1:2, 1:1, and 2:1 available via feedback configuration
• Additional outputs at 2X and Q/2 system frequencies, plus inverted Q5
• All outputs provide ±36 mA drive at CMOS levels, compatible with TTL inputs

Clock Generators, PLLs, Frequency Synthesizers Applications

• Clock distribution for high performance PCs and workstations
• Synchronous distribution of central system clocks to multiple boards
• Multiplying low frequency input clocks to higher local system frequencies

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the EI suffix indicates a Pb-free 28-lead PLCC package (Case 776-02). Confirm the FN55 speed grade corresponds to the required 55 MHz 2X_Q maximum operating frequency. Ensure the application environment stays within the specified 0°C to +70°C temperature range and 5.0 V ± 5% supply voltage.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select based on required output skew (< 500 ps rising edge) and drive strength (±36 mA). Choose between FN55 (55 MHz 2X_Q) or FN70 (70 MHz 2X_Q) speed grades depending on target frequency. Use FREQ_SEL pin logic to adjust VCO operation for low-frequency reference inputs if necessary. Ensure proper loop filter components are included for stable PLL operation.

Clock Generators, PLLs, Frequency Synthesizers Part Context

The MC88915 is part of the IDT/ICS CMOS PLL Clock Driver family. The EI suffix specifically denotes the Pb-free version of the standard 28-lead PLCC package. This component is designed to replace older clock buffer solutions by integrating PLL functionality directly into the distribution stage, reducing board complexity and jitter.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material. Verify compatibility with existing PCB footprints and signal integrity requirements when considering alternative low-skew clock drivers.