MC88LV915TFN

Clock Generators, PLLs, Frequency Synthesizers Overview

The MC88LV915TFN is a low skew CMOS PLL clock driver designed for high-performance PC and workstation clock distribution. It locks multiple outputs to an input reference clock with minimal delay. The device provides five Q outputs (Q0–Q4) with less than 500 ps skew, an inverted Q5 output, a 2X_Q output running at twice the frequency, and a Q/2 output. It operates on a single 3.3V supply within a 0°C to 70°C temperature range. Maximum operating frequencies are 100 MHz for the 2X_Q output and 50 MHz for the Q outputs. Outputs feature ±36 mA drive capability compatible with CMOS and TTL levels.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Five Q outputs (Q0–Q4) with output-to-output skew less than 500 ps
• Additional outputs include 2X_Q (double frequency), Q/2 (half frequency), and inverted Q5
• Input/output phase-locked frequency ratios of 1:2, 1:1, and 2:1 via feedback configuration
• Test mode functionality allows low-frequency board testing with direct SYNC gating

Clock Generators, PLLs, Frequency Synthesizers Applications

• High-performance personal computer clock distribution
• Workstation system clock synchronization
• Multi-board synchronous clock distribution systems

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the FN suffix indicates a Plastic PLCC package (Case 776-02). Confirm the device meets the recommended operating conditions of 3.3V ±0.3V supply voltage and 0°C to 70°C ambient temperature. Ensure loop filter components match the datasheet recommendations for stable operation.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select this component when low skew distribution from a single reference is required. The FREQ_SEL pin allows divide-by-2 feedback for optimal VCO operation with low-frequency inputs. Use the OE/RST pin for 3-state control during board testing. Ensure the input frequency falls between 5 MHz and the respective Fmax specification.

Clock Generators, PLLs, Frequency Synthesizers Part Context

Originally manufactured by Motorola, Inc., this part is now distributed under NXP USA Inc. branding following corporate acquisitions. The datasheet revision is Rev 3, dated 08/2001. The device belongs to the MC88LV series of low voltage clock drivers.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Verify compatibility with existing loop filter designs if substituting with other PLL clock drivers.

Clock Generators, PLLs, Frequency Synthesizers FAQ

How does the FREQ_SEL pin affect the VCO operation?

The FREQ_SEL pin selects between divide-by-1 and divide-by-2 in the PLL feedback path. Holding it low (÷2) allows the VCO to run in its optimal range (>20MHz) when using a low-frequency reference clock.

What is the function of the PLL_EN pin?

Holding PLL_EN high enables normal phase-locked operation. Pulling it low disables the VCO and puts the device in a static test mode, allowing the input clock to bypass the VCO for low-frequency board testing.

How is the LOCK indicator used?

The LOCK output goes high when the loop achieves steady-state phase and frequency lock. It goes low if phase-lock is lost or if the PLL_EN pin is low. It asserts no later than 10ms after receiving a SYNC signal and full power.