8-bit shift register with open-drain outputs — what it does on your board
The Texas Instruments TPIC6C596N is an 8-bit serial-to-parallel shift register with open-drain outputs, in a 16-pin DIP package for through-hole mounting. It takes serial data in and presents it as eight parallel open-drain outputs, each rated to sink current for driving loads like relays, solenoids, indicator LEDs, or the gate of a small MOSFET. The supply range is 4.5V to 5.5V, so it lives on a regulated 5V rail — not a 3.3V logic bus.
Open-drain output — why it matters for driving loads
The open-drain output means each of the eight bits can sink current from an external supply, but cannot source it. This makes the part a natural fit for driving loads that share a common positive rail — think a bank of N-channel MOSFET gates, a relay coil with a flyback diode, or a row of LEDs with series resistors. The open-drain structure also allows wired-OR connections if you need to combine outputs from multiple registers on the same bus.
The through-hole DIP package is straightforward to hand-assemble or rework in a lab, and it stands up to vibration better than a fine-pitch SMD in some panel-mount applications.