USB-to-serial bridge with I²C and SPI — what this chip does
The Infineon CY7C65211A-24LTXI is a USB 2.0 bridge IC that converts USB traffic to UART, I²C, or SPI protocols, making it a single-chip solution for adding a serial communications port to a host system through a standard USB connection. It belongs to the CapSense® series, though its primary function here is the bridge, not capacitive sensing. The 24-UFQFN package with exposed pad (4x4mm) keeps the footprint small for space-constrained designs like portable instruments or embedded modules.
The 1.71V to 5.5V supply range covers both legacy 3.3V logic and newer 1.8V-core systems, plus it can drive 5V-tolerant I²C buses without a level shifter. That saves a translator IC and the board area it would take. The 20mA supply current is the active draw during USB communication — budget for it on the 3.3V or 5V rail, but it's low enough that a standard linear regulator can feed it without thermal concern. No derating needed for ambient temperatures inside a ventilated enclosure.
Package and layout — the exposed pad matters
The 24-UFQFN with exposed pad is a 4x4mm body with a thermal pad underneath. The pad also serves as a low-inductance ground return for the USB signals, which helps with signal integrity on the D+ and D- lines.