The MAX3349E is a ±15kV ESD-protected, USB transceiver from MAXIM that provides a full-speed USB interface to a lower voltage microprocessor or ASIC. The device supports enumeration, suspend, and VBUS detection. A special UART multiplexing mode 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 MAX3349E features a separate UART voltage supply input to support legacy devices using +2.75V signaling. The MAX3349E supports a maximum UART baud rate of 921kbaud. Upon connection to a USB host, the MAX3349E enters USB mode and provides a full-speed USB 2.0-compliant interface through VP, VM, RCV, and OE. The MAX3349E 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 MAX3349E 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 MAX3349E is a full‑speed USB 2.0 transceiver that also supports a UART multiplexing mode, allowing external UART signals to be routed to the USB D+ and D‑ lines. It provides ±15 kV ESD protection, internal series termination, a 1.5 kΩ pull‑up on D+, and a separate UART voltage supply for legacy devices.
Key specifications include operation from –40 °C to +85 °C, a maximum UART baud rate of 921 kbaud, VBUS input range of 3.0 V‑5.5 V, and availability in 16‑pin TQFN (4 mm × 4 mm) and 16‑bump UCSP (2 mm × 2 mm) packages.
| Operating temperature range | -40 °C to +85 °C |
|---|---|
| Maximum UART baud rate | 921 kbaud |
| Package options | 16‑pin TQFN (4 mm × 4 mm) and 16‑bump UCSP (2 mm × 2 mm) |
| VBUS input range | 3.0 V to 5.5 V |
| VUART input range | 2.7 V to 3.3 V |
| Internal pull‑up resistor on D+ | 1.5 kΩ |
The MAX3349E supports a maximum UART baud rate of 921 kbaud.
It is offered in a 16‑pin TQFN (4 mm × 4 mm) package and a 16‑bump UCSP (2 mm × 2 mm) package.
The device operates from –40 °C to +85 °C.