Quad 3-state buffer — 2V to 6V supply, 7.8mA drive per channel
The SN74HC125DT is a Texas Instruments 74HC-series quad buffer with non-inverting logic and independent 3-state output enables on each of its four elements. Each element buffers one bit, so the part handles four separate signal paths in a single 14-SOIC package. Supply voltage spans 2V to 6V, making it a direct fit for 3.3V and 5V mixed-voltage systems without a separate level translator. The 7.8mA source and sink capability per output is typical for the HC family — enough to drive a CMOS input bank or a low-current LED indicator, but not a relay coil or bus transceiver without a buffer stage.
3-state bus isolation — each channel gates independently
Each of the four buffers has its own output-enable pin. When the enable is asserted low, the output follows the input; when high, the output goes to high-impedance (3-state). This lets multiple devices share a common data bus — only one buffer's output is active at a time, preventing contention. The 3-state outputs are the key feature for bus-oriented designs: a microcontroller's address or data lines can be isolated from the peripheral bus until the chip-select line activates the buffer. Without 3-state, every connected device would fight the bus.
Industrial temperature grade and SOIC-14 footprint
The 14-SOIC package (3.90mm body width, 1.27mm pitch) is a standard footprint for automated pick-and-place and reflow assembly.