SPI GPIO expander for automotive sensor readback
The NXP PCA9704PW/Q900J is an SPI-controlled GPIO expander with eight input-only channels, each presenting an open-drain output back to the host microcontroller. The 5 MHz SPI clock and dedicated interrupt output let a master poll all eight inputs in under 2 µs — fast enough to catch edge-triggered events from limit switches or Hall-effect sensors on a motor-drive control board. An engine-bay ECU or transmission controller that sees 105°C on a summer grade still has thermal margin.
16-TSSOP footprint and hot-air rework profile
The 16-TSSOP package has a 4.40 mm body width and 0.65 mm lead pitch — a standard SOIC-16 footprint with a narrower body. The leads are gull-wing, so a hot-air station at 300°C with a fine nozzle lifts the part cleanly without heating the adjacent passives. The exposed die pad is absent on TSSOP, so the thermal path is through the leads only; keep the copper pour under the package solid to pull heat from the mould compound during reflow. Tape & Reel (TR) and Cut Tape (CT) options are available for both production reels and prototype quantities. The CT option is handy for bench bring-up — one reel of 2500 pieces is a lot of inventory for a first spin. ROHS3 compliant, no exotic finishes that would require a separate lead-free profile.