Quad buffer for mixed-voltage bus isolation
The TC74LCX125FK(EL,K) is a Toshiba 74LCX-series quad buffer with non-inverting logic and 3-state outputs. Each of the four elements handles one bit, with a per-channel output drive of 24mA sourced or sunk.
Each output can deliver 24mA high or low, which is enough to drive a lightly loaded backplane trace or a bank of CMOS inputs without an external line driver. At 3.3V the 24mA figure holds across the full temperature range, so the fan-out to downstream loads stays predictable. If you are buffering a shared data bus or control line that multiple peripherals pull on, the 3-state output lets you float the bus when the buffer is disabled — no contention, no extra bus-hold logic.
1.65V to 3.6V supply — why it matters for mixed-voltage designs
The 1.65V lower rail means this part runs directly off a 1.8V core supply without a separate regulator. At the high end, 3.6V covers 3.3V nominal with margin for ripple. Just watch the input thresholds: at 1.8V the VIH minimum is typically 0.65 × VCC, so a 1.2V signal will not reliably register as a logic high.
Package and footprint: 14-VFSOP / 14-VSSOP
The part ships in a 14-VFSOP package measuring 0.118" (3.00mm) body width. Surface-mount only, so plan for a standard 0.65mm pitch land pattern.
For new designs and sustaining production, this part is a safe BOM line without obsolescence pressure.