NB2309AC1D

Overview

The NB2309AC1D is a 3.3 V zero delay clock buffer manufactured by onsemi, designed for high-speed clock distribution in PC, workstation, and datacom applications. It accepts one reference input and drives nine low-skew outputs grouped into two banks of four plus one feedback output. The device utilizes an on-chip PLL to lock to the input clock on the REF pin, achieving zero input-output propagation delay when outputs are uniformly loaded. Operating within a frequency range of 15 MHz to 133 MHz, it features less than 250 ps output-to-output skew and under 200 ps cycle-to-cycle jitter. The part is housed in a 16-pin SOIC package.

Feature Summary

• Zero delay buffer with on-chip PLL locking to REF pin input
• Drives nine low-skew outputs (4+4+1 configuration) from a single reference
• Output-to-output skew guaranteed less than 250 ps
• Cycle-to-cycle jitter less than 200 ps at 66.67 MHz
• Test mode allows bypassing PLL to apply input clock directly to outputs

Applications

• High-speed clock distribution in PC and workstation systems
• Datacom and telecom equipment requiring low-jitter clocks
• Pentium-based system clock generation
• PCI bus frequency compatible clock buffering

Procurement Notes

Verify the ordering suffix 'C' indicates Commercial temperature range (0°C to 70°C) and '1' denotes the standard drive version. Confirm package type matches the required footprint, as this specific part number corresponds to the SOIC-16 package. Check for Pb-free variants if environmental compliance is mandatory, identified by the 'G' suffix in the ordering information.

Selection Notes

Select the NB2309AC1D for commercial temperature applications requiring standard drive strength. For industrial temperatures (-40°C to 85°C), choose the NB2309AI1D variant. If faster rise and fall times are needed for higher drive capability, consider the -1H versions such as NB2309AC1HD. Ensure load capacitance requirements are met: 30 pF for frequencies below 100 MHz and 10 pF for 100 MHz to 133 MHz.

Part Context

The NB2309A series includes the NB2305A (8-pin, 5 outputs) and NB2309A (16-pin, 9 outputs). The NB2309AC1D is the commercial temperature, standard drive version in a 16-pin SOIC package. It shares functional characteristics with the NB2309AI1D (industrial temp) and NB2309AC1HD (high drive commercial) but differs in operating temperature range and output drive current specifications.

Replacement Considerations

Direct replacements include NB2309AI1D for industrial temperature operation or NB2309AC1HD for higher drive strength. Cross-family alternatives like the NB2304A provide fewer outputs (4) in an 8-pin package. Verify that any substitute maintains the 16-pin SOIC footprint and supports the required 133 MHz frequency with similar skew specifications.