Would be interesting which datecode MisterDiodes has on his LTC6655.
With best regards
Andreas
This was an order received in late March / April, dates I believe were third week Jan, direct from LT. They were replaced though with in spec parts. LT seemed to be happy to exchange, and it seemed to be no surprise. They didn't offer any story that I know of, but that something slipped past QC testing. This is not the usual routine for them, so it seems like something is off.
It is harder to keep the noise down with diffused voltage setting resistors built on the die - a lot can go wrong there and it's not the substrate necessarily.
The bottom line is it's always a good idea to spot-check all incoming shipments of the before assembling a whole batch of product.
Off topic but: Even the distributors are not paying close attention recently- Today I reviewed an incoming order from DigiKey with about 135 line items - three bags were shorted (for instance we got 45ea. 18 pin sockets instead of 50), and 2 bags had the wrong IC, and one IC bag was packed up with the wrong package type (It was supposed to be TO-220 but we got SMT's) and so on. The order BOM was correct, the packing list was correct - it was just stuff mis-packed at their end. That has happened on every incoming order from them in the last few weeks...Take a look at your goods carefully. Especially if you order higher grade Vrefs or amps, make sure you receive the quality grade you paid for.