What this TI buffer does on the bus
The Texas Instruments SN74AC240QPWRG4Q1 is a dual 4-bit inverting buffer with 3-state outputs, part of the 74AC family qualified to AEC-Q100 for automotive use. It sits between a microcontroller or ASIC and a shared data bus, inverting the signal while providing enough drive to fan out to multiple loads. The 3-state outputs let you isolate the bus when the buffer is disabled — useful in multiplexed address/data lines or shared peripheral buses where only one driver talks at a time.
Supply range and temperature — what they mean for fit
The 2V to 6V supply range covers 3.3V and 5V logic rails without a level translator, and the -40°C to 125°C operating temperature matches the under-hood and chassis-domain requirements for automotive ECUs. The 24mA source and sink capability at both output states gives enough margin to drive a 5V CMOS bus or a bank of optocoupler inputs without external buffers.
Package and footprint reality
20-pin TSSOP with 0.173-inch body width and 4.40mm pitch — standard footprint that matches many existing 20-pin TSSOP buffer layouts. Surface-mount only; no through-hole variant in this series.
Lifecycle and compliance
The AEC-Q100 qualification means it has passed the stress tests for automotive-grade reliability — thermal cycling, humidity bias, and latch-up immunity — which also makes it a safe choice for industrial or outdoor telecom where extended temperature and vibration are the norm.