Capacitive touch controller in a 6x6 mm BGA
The ATMXT640UD-CCUBHA1 is a 2-wire capacitive touchscreen controller from Microchip's MAXTOUCH UD series, built for home appliance touch interfaces. It communicates over I²C or SPI and draws 40 mA from a supply that can be as low as 1.71 V on the core side or 3.14 V on the touch side. Housed in an 88-ball UFBGA measuring 6x6 mm, this package is a challenge for hand-soldering — you'll want a stencil and a reflow profile, not an iron. The 0.5 mm ball pitch means the PCB layout needs careful fan-out; a four-layer board with microvias is the practical minimum for routing all signals.