The STMicroelectronics digital capacitor controller is used to control adjustable capacitors

     STMicroelectronics STHVDAC-253C7 digital capacitor controllers are used to control adjustable capacitors, for example, STMicroelectronics STPTIC series adjustable capacitors, The advantages of this product are that it can reduce the size of the antenna tuning circuit, reduce the bill of materials (BoM) cost and power consumption, and stabilize the RF performance of the smartphone. Using STHVAC-253C7 controllers and STPTIC capacitors for impedance matching and frequency tuning can almost completely eliminate the impact of external environmental changes on RF performance, allowing mobile phone users to get stronger reception signals, fewer dropped calls, faster data rates, and longer battery life.

     Using STMicroelectronics advanced 0.18µm BCD8 process and 0.35mm pitch flip chip package, STHVAC-253C7 is 50% smaller than the previous generation, and the operating current is reduced by half. In addition, the new controller can be used with the latest 0402 chip size inductors, eliminating the need for external Schottky diodes, further reducing the overall circuit area.

     As a high-voltage digital-to-analog converter (DAC) designed to provide bias for tunable capacitors, the STHVDAC-253C7 controller provides users with three outputs to control three different capacitors in GSM/WCDMA/LTE multi-band handsets. St has also integrated a boost converter to provide the 0V-24V bias required to adjust the capacitance. The STHVDAC-253C7 supports standard MIPI RFFE (RF Front end) commands issued by the system transceiver, supports three RFFE Unique Slave ID (USID) identifiers, and one STHVDAC-253C7 can manage three separate antennas.

     STHVDAC-253C7 supports common antenna tuning modes, including normal modes with new and old output voltage switching times of less than 10µs; Turbo mode that reduces the time to build up the output capacitor voltage; Old and new voltage switch delay 512µs to 16.84ms adjustable Glide mode. Glide mode enables the smoothest voltage conversion and meets requirements such as 3GPP phase discontinuity. In addition, the capacitor controller provides a GPIO pin for managing two controllers connected on the same RFFE bus in a dual tuner phone, for switching controller registers to manage antenna diversity designs, or for adjusting register Settings to correct antenna response when inserting a USB cable.