The MAX3349EA is a USB transceiver from Texas Instruments that provides a full-speed USB interface to a lower voltage microprocessor or ASIC. The device supports enumeration, suspend, and VBUS detection. MAX3349EA features a special UART multiplexing mode that routes external UART signals (Rx and Tx) to D+ and D-, allowing the use of a shared connector to reduce cost and part count for mobile devices. The UART interface allows mobile devices such as PDAs, cellular phones, and digital cameras to use either UART or USB signaling through the same connector. The MAX3349EA features a separate UART voltage supply input to support legacy devices using +2.75V signaling. The MAX3349EA supports a maximum UART baud rate of 921kbaud. Upon connection to a USB host, the MAX3349EA enters USB mode and provides a full-speed USB 2.0 compliant interface through VP, VM, RCV, and OE. The MAX3349EA features internal series termination resistors on D+ and D-, and an internal 1.5kΩ pullup resistor to D+ to allow the device to logically connect and disconnect from the USB while plugged in. A suspend mode is provided for low-power operation. D+ and D- are protected from electrostatic discharge (ESD) up to ±15kV. The MAX3349EA is available in 16-pin TQFN (4mm x 4mm) and 16-bump UCSP™ (2mm x 2mm) packages, and is specified over the -40°C to +85°C extended temperature range.
The MAX3349EA is a USB 2.0 full‑speed transceiver that can also operate in UART multiplexing mode, allowing a single connector to carry both USB and UART signals for mobile devices such as cell phones, PDAs and digital cameras. It provides ESD protection up to +15 kV, internal series termination, a 1.5 kΩ pull‑up resistor on D+, and a built‑in linear regulator for USB power.
Key specifications include a maximum UART baud rate of 921 kbaud, operation over a –40 °C to +85 °C temperature range, and availability in 16‑pin TQFN (4 mm × 4 mm) or 16‑bump UCSP (2 mm × 2 mm) packages. The datasheet also lists absolute maximum ratings, detailed electrical characteristics, timing diagrams, pin descriptions and package dimensions.
| Maximum UART baud rate | 921 kbaud |
|---|---|
| ESD protection (D+ and D-) | +15 kV |
| Operating temperature range | -40 °C to +85 °C |
| Internal pull‑up resistor on D+ | 1.5 kΩ |
The MAX3349EA supports a maximum UART baud rate of 921 kbaud.
It is protected against electrostatic discharge up to +15 kV.
It operates from –40 °C to +85 °C.