1. 2305-1HDCG8 Substitution Conclusion The 2305-1HDCG8 is a potential substitute for the PI6C2405A-1HWIEX in core functionality, as both are zero‑delay buffers supporting 133 MHz operation, a 1:5 output ratio, and 3.3 V supply, with compatible packages. Key differences are: the input level is LVTTL (rather than the original TTL), the outputs support multiple types (CMOS/LVCMOS/TTL), and the PLL supports bypass mode. There may be slight differences in input threshold voltage (LVTTL thresholds are typically lower), so compatibility with the preceding stage signal must be verified. While output flexibility is improved, load matching should be considered. The PLL bypass feature provides additional clock‑path control, which is advantageous during system debugging or in low‑power scenarios. If the system signal levels meet LVTTL requirements and strict TTL interface consistency is not required, this part can be used as a replacement.