5V bus transceiver in a 20-SOIC — what the 64 mA sink buys you
The Texas Instruments SN74F245DW is an octal (8-bit) bidirectional bus transceiver from the 74F family, with non-inverting 3-state outputs, designed for 5V supply rails.
Output drive — the 64 mA sink is the spec that matters
The SN74F245DW lists two output current pairs: 3 mA source / 24 mA sink on one set, and 15 mA source / 64 mA sink on the other. The 64 mA sink figure is what distinguishes this part from the 74LS645-1N (15 mA sink) or the 74ABT2245DW (32 mA sink). For a 5 V bus with multiple fan-out or long PCB traces, the extra sink margin means cleaner low-level noise margins and fewer signal-integrity issues at the receiver. The 15 mA source side still handles typical TTL fan-out, but the 64 mA sink is the spec to budget against when sizing the bus load.
