Octal bus transceiver for mixed-voltage backplanes
The Texas Instruments SN74HC245PW is an octal (8-bit) non-inverting bus transceiver from the 74HC family, with 3-state outputs on both the A and B ports. It handles bidirectional data flow between two buses under direction (DIR) and output-enable (OE) control. The supply range of 2V to 6V covers both 3.3V and 5V logic rails, making it a common choice for mixed-voltage backplanes, memory interfaces, and peripheral bus isolation in industrial control and telecom equipment.
2V to 6V supply — 3.3V and 5V compatibility confirmed
The 2V to 6V supply range directly answers the most common fit question: yes, the SN74HC245PW is compatible with 3.3V logic. It operates from 3.3V ±10% with margin, and also runs on 5V for legacy TTL-level buses. The 7.8mA output drive at both high and low levels is typical for HC-series CMOS — enough to drive a few standard CMOS inputs but not high-current loads. If you need to drive longer traces or multiple fan-outs, budget for a buffer stage or move to a higher-drive family like 74HCT or 74ACT.
Package and mounting
The 20-TSSOP package (4.40mm body width, 0.65mm pitch) is reworkable with hot air if you have a fine nozzle and steady hands. The thermal mass is low, so it heats quickly; use a 260°C peak profile with a preheat around 150°C to avoid lifting pads. No exposed pad, so inspection is straightforward.
Active and ROHS3 compliant
It is ROHS3 compliant, so it passes the material restrictions for EU and most global markets. No LTB risk, no urgent need to qualify a second source — though the 74HC245 function is second-sourced by multiple vendors if you want a dual-source strategy.