Part Number: CD74HCT126
Hi
Older version of HCT126 (circa 2017 TI Marking): Functions normally under the same system and conditions.
• Newer version of HCT126 (circa 2024 TI Marking): After power-on, the buffer intermittently fails to output normally, requiring a power cycle or condition switching to recover.
Anomaly: No output from all four buffers (four groups).
• Enable and input signals are normal.
• Recovery occurs after a power cycle. 2017 vs 2021/2024 Differences:
• No significant difference in waveform under normal conditions.
• Difference occurs at the initial power-up state.
o 2017: Normal operation after power-up.
o New version: No buffer operation after power-up.
Failure Rate: Occurs in batches after PCN (100%).
PCN, released by TI on 2021/12/22
(Note: The right image shows a 2017 TI 74HCT126M, which is functioning normally; the left image shows a 2024 TI 74HCT126M, which exhibits intermittent abnormalities.)
