What this 8-bit latch does on your board
The SN74HCS573RKSR is an 8-bit D-type transparent latch with tri-state outputs — when the latch-enable (LE) pin is high, the outputs follow the inputs; when LE goes low, the last input state is held. The 8:8 circuit means eight inputs feed eight latched outputs, each independently controlled by the same LE signal. Supply voltage spans 2V to 6V, so it works on 3.3V and 5V logic rails without a separate level translator. Propagation delay is 11ns typical, fast enough for most parallel bus applications below 90 MHz. Output drive is 7.8mA per pin in both high and low states — enough to drive a handful of CMOS inputs or a low-power LED directly, but not a heavy bus without buffering.
Package and rework considerations
Housed in a 20-VQFN (2.5x4.5mm) with an exposed pad — the pad is the thermal and electrical ground path. The small body and fine pitch mean a hot-air rework station with a fine nozzle is the safe way to remove it; a soldering iron alone risks lifting the pad. Pin 1 is marked by a dot on the top of the package — check orientation before placement. The exposed pad needs a solder paste stencil opening that matches the datasheet footprint; too much paste and the part floats off the pads. Operating temperature range is -40°C to 125°C, so it survives the reflow profile and the board's working environment without derating.
Sourcing and lifecycle reality
It is a current-production part, so new designs can commit it without worrying about a last-time-buy window. Supplied in Tape & Reel (standard 7-inch reel) or Cut Tape — the reel format suits automated pick-and-place; Cut Tape works for prototypes and small runs. Pricing and current availability are confirmed at quote time against an RFQ. The part is sourced through authorized distribution channels — no broker or surplus channel needed for an active line.