Single-gate buffer with 3-state output for mixed-voltage buses
The Texas Instruments SN74LVC1G126DBVR is a single-bit, non-inverting buffer with a 3-state output, part of the 74LVC family of low-voltage CMOS logic. The output enable (OE) pin, active high, puts the output into high-impedance when low, which is the key difference from the SN74LVC1G125 (active-low OE). Each output can sink or source 32mA, enough to drive a handful of CMOS loads or a short PCB trace.
It means this single gate can sit on a 1.8V FPGA I/O bank, a 3.3V microcontroller bus, or a 5V legacy peripheral interface without a separate regulator. The wide tolerance also absorbs supply ripple: a 3.3V rail that droops to 3.0V under load still keeps the buffer in spec.
Package and footprint — SOT-23-5 layout notes
The SN74LVC1G126DBVR ships in a SOT-23-5 package (also designated SC-74A / SOT-753). The 0.95 mm pitch and 2.9 mm body length fit into tight board areas — useful for adding a buffer near a connector or a sensor without a separate logic IC. MSL is 1 (no bake required before reflow if the bag seal is intact), which simplifies assembly logistics.
For a production BOM, this removes the single-source risk that comes with an obsolete or phase-out part. The base product number 74LVC1G126 covers the entire family, so if the DBVR (SOT-23-5) reel variant is unavailable, the same die in a different package (e.g., DCKR in SC-70) may be a drop-in alternative after a layout change.