AN4440 Datasheet, PDF (1/36 Pages) STMicroelectronics – RFFE HVDAC control

AN4440
Application note
RFFE HVDAC control
Pascal Paillet
Introduction
The purpose of this application note is to familiarize mobile phone designers with RFFE
HVDAC control. Common tasks are explained and more advanced functions such as trigger
mode, extended mode or USID reprogramming are also detailed. Each frame or the
significance of the sequence is explained and illustrated with concrete examples tested with
the antenna utility tools (AUT) and the HVDAC control board either in full automatic mode or
manually (bit by bit).
HVDAC is used in mobile phones for antenna tunability. This is a programmable DC/DC
converter supplying the bias voltage for PTIC variable capacitors.
Although both SPI and RFFE interface options exist, this document concerns the latter
which is now mainstream.
April 2014
DocID025913 Rev 1
1/36
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