Single open-drain buffer for mixed-voltage buses
The open-drain output can sink up to 32 mA, which is enough to drive an LED, a small relay coil, or pull a bus line low in a wired-OR configuration. The SC-70-5 package (also known as SOT-353) keeps the footprint small for dense PCBs.
The 1.65 V minimum supply means this buffer works with sub-1.8 V cores and I/O banks, while the 5.5 V maximum covers legacy 5 V TTL buses without a separate level shifter.
Because the output is open-drain, the high level is determined by an external pull-up resistor tied to the desired logic voltage. This is the standard approach for I²C, SMBus, and other multi-drop buses where multiple devices share a line. The 32 mA sink capability handles the pull-up current and any additional load without exceeding the device rating. There is no internal pull-up, so the designer must add one externally if the application requires a defined high state.
