8-bit open-drain transceiver for 5V buses
The 74FCT621TSOG is an 8-bit non-inverting transceiver from Renesas' 74FCT logic family, built for bidirectional data flow on 5V buses with open-drain outputs. It operates from a 4.75V to 5.25V supply and sinks 48 mA per output on the low side, or 64 mA depending on the direction — the open-drain structure means the high-level output is pulled up externally, so the actual drive current is set by the pull-up resistor and the bus capacitance. The single-element, 8-bit layout maps cleanly onto an 8-bit data bus or a byte-wide control signal set.
20-SOIC package and rework considerations
Where is pin 1? The SOIC-20 uses a molded notch and a dot on the top surface — standard orientation. The supplier device package is 20-SOIC, matching the JEDEC MO-119 variation for the wide body.