Mixed-voltage bus bridge — what this part does
The TI SN74AVCH4T245D is a dual 4-bit translation transceiver from the 74AVCH series. It sits between two voltage domains — say a 1.8V microcontroller and a 3.3V peripheral — and passes data in either direction with the direction control per element. Each of the two elements handles four bits independently, so you get two separate bidirectional translation channels in one 16-SOIC package. The supply range spans 1.2V to 3.6V, which covers the common logic levels: 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V. Output drive is 12 mA source and 12 mA sink per channel — typical for the 74AVCH family and adequate for point-to-point board-level interconnect or lightly loaded buses. The 3-State outputs let you share a bus with other transceivers without contention.
That means no last-time-buy math for a new design.