STMicroelectronics’ STHVDAC-253C7 digital controller for tunable capacitors promises to shrink the size of a smartphone design’s bill of materials (BoM) and the power consumption of antenna-tuning circuits. Using the device with STPTIC capacitors for impedance matching and frequency tuning, reportedly, almost eliminates the effects of environmental variations, resulting in stronger signal reception, fewer dropped calls, faster data rates, and longer battery life for handset users.
Exploiting the company’s 0.18 µm BCD8 process and 0.35-mm pitch flip-chip package, the STHVDAC-253C7 is 50% smaller than its predecessor and consumes half the operating current. In addition, the controller works with the latest 0402 chip-size inductors and requires no external Schottky diode, thereby reducing the overall circuit footprint even further.
As a high-voltage digital-to-analog converter (DAC) specifically designed to generate bias voltages for tunable capacitors, the STHVDAC-253C7 provides three outputs suitable for tuning three different capacitances in multi-band GSM/WCDMA/LTE handsets. The device also integrates the boost converter needed to generate bias voltages across the full capacitor-tuning range from 0V to 24V. It accepts standard MIPI RFFE (RF Front-End) commands from the system transceiver. Support for three RFFE Unique Slave IDs (USID) allows a single STHVDAC-253C7 to manage up to three separate antennas.
The STHVDAC-253C7 supports commonly used antenna-tuning modes, including Normal mode, which moves to a newly commanded output voltage within 10µs; Turbo mode, optimized for minimum settling time; and Glide mode, with programmable delay from 512µs to 16.84ms for the smoothest transitions and to meet requirements such as 3GPP phase discontinuity. A GPIO pin is provided that can be used for managing two controllers on the same RFFE bus in dual-tuner handsets. It also allows switching between registers to manage antenna-diversity designs or adjust settings to correct the antenna response when a USB cable is plugged in.
Pricing options for the STHVDAC-253C7 start from $0.19 each/1,000. For more details, visit the product page.