The MIPI Envelope Tracking Interface provides a point-to-point interface between a radio transmitter and an envelope tracking power supply (ETPS). The specification enables mobile device manufacturers to deploy envelope tracking technology in radio transmitter.
Envelope tracking is used to reduce power consumption of the RF power amplifier, which in turn improves the efficiency of the transmitter. Envelope tracking is particularly important when a device is transmitting at a high data rate on 4G and other cellular standards that use advanced modulation schemes, a standard feature in LTE.
The MIPI eTrakSM Envelope Tracking Interface facilitates interoperability between transmitters and the ETPS to provide flexibility in selecting components, streamline development and lower development costs. The specification provides a high-speed, unidirectional analog differential interface that includes a low-power PHY. It provides bandwidth to support LTE operation at 20 MHz.