The SN74ALS644A-1DW: Bus transceiver from the ALS series, active lifecycle, RoHS non-compliant.
For legacy repair, maintenance, or military/aerospace applications where leaded solder is still permitted, this is a straightforward drop-in.
Sourcing posture
If you are filling a BOM line for a production run or a repair batch, submit an RFQ; we will source from franchised or vetted independent channels and quote you the landed cost.