An antenna-tuning circuit from STMicroelectronics has a 4-channel output for adjusting up to four tunable BST capacitors in the antenna-matching circuits of multi-band GSM/WCDMA/3G-LTE smartphones.
The chip also supports the MIPI Alliance RF Front End (RFFE), an interface standard increasingly being used in cellular radio sub-system design.
The STHVDAC-304MF3 is controlled via an RFFE-compliant 1.8V interface, and comprises a high-voltage digital-analogue converter (HVDAC) for generating capacitor-tuning voltages from 2V to 20V.
Source:
http://www.electronicsweekly.com/Articles/2013/04/02/55865/st-multi-band-antenna-tuning-chip-supports-mipi.htm
