USB peripheral controller with SPI host interface
The MAX3420EETG+ is a USB 2.0 full-speed peripheral controller from Maxim Integrated that connects to a host microcontroller over an SPI interface. It handles all USB protocol and transaction management, offloading the host MCU from low-level USB timing. The 3V to 3.6V supply range and 15 mA supply current make it a fit for 3.3V logic systems where USB connectivity is needed without a dedicated USB-capable MCU. Typical applications include adding USB device capability to embedded systems, industrial instruments, and legacy equipment retrofits.
The 24-TQFN (4x4 mm) package is a small footprint but requires a clean reflow profile and X-ray inspection for hidden solder joints under the exposed pad. The exposed pad also provides a thermal path; a via array under the pad to a ground plane keeps the junction temperature in check.