STMicroelectronics' STHVDAC-253C7 digital capacitance controller is used to control tunable capacitors, such as STMicroelectronics' STPTIC series of tunable capacitors. This product has the advantage of reducing the size of the antenna tuning circuit and reducing bill of materials (BoM) costs. And power consumption to stabilize the RF performance of smartphones. Using the STHVDAC-253C7 controller 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 obtain stronger received signals, fewer dropped calls, and faster. Data rate, and longer battery life.
Using ST's advanced 0.18μm BCD8 process and 0.35mm pitch flip-chip package, the STHVDAC-253C7 is 50% smaller than the previous generation and reduces operating current by half. In addition, the new controller can be used with the latest 0402 chip size inductors, eliminating the need for an external Schottky diode, further reducing the overall circuit area.
As a high voltage digital-to-analog converter (DAC) designed to bias the tunable capacitors, the STHVDAC-253C7 controller provides the user with three outputs for controlling three different capacitors in a GSM/WCDMA/LTE multi-band handset. STMicroelectronics also integrates a boost converter that provides the 0V-24V bias required to adjust the capacitance. The STHVDAC-253C7 supports standard MIPI RFFE (radio front-end) commands from system transceivers and supports three RFFE Unique Slave ID (USID) identifiers. One STHVDAC-253C7 can manage three independent antennas.
The STHVDAC-253C7 supports common antenna tuning modes, including normal mode with new and old output voltage switching time less than 10μs; Turbo mode that shortens the output capacitor voltage settling time; new and old voltage switching delays from 512μs to 16.84ms can be set in Glide mode. Glide mode enables the smoothest voltage conversion and meets 3GPP phase discontinuities. In addition, the capacitor controller provides a GPIO pin for managing two controllers connected to the same RFFE bus in a dual tuner handset, and for switching controller registers to manage antenna diversity design, or when When the USB cable is plugged in, it is used to adjust the register settings to correct the antenna response speed.
STHVDAC-253C7 is now in the pre-production stage, using 12-ball 0.35mm pitch WLCSP flip-chip package, ready for design and development samples.
