Date: 12/11/2012

Tunable integrated capacitors for adjusting RF power in mobiles as per need

STMicroelectronics' new ParaScan Tunable Integrated Capacitors (STPTIC) are electrically adjustable to maintain efficient transfer of energy from the handset amplifier to the antenna under various operating conditions. The STPTIC helps in adjusting radiated RF power for better call performance, overcoming the challenges of use in multiple frequency bands, when the handset is held close to the user’s ear or when it is moved away from the head, while minimizing amplifier power consumption for longer battery life.

ST explains unlike alternatives that typically contain multiple switched capacitors, the STPTIC allows capacitance to be adjusted smoothly, without steps, for greater precision. The STPTIC is also smaller, combining a single, variable capacitor with control circuitry using ST’s Integrated Passive and Active Device (IPAD) technology.

“Our latest and most advanced STPTIC family now delivers an even more compelling option for future 4G LTE handsets, which will demand high wireless performance for reliable voice and high-speed data communications with longer battery life” said Ricardo De-Sa-Earp, Group VP and General Manager, Application-Specific Discretes & IPAD Division. “Two of the world’s top five handset manufacturers have already chosen this technology for antenna matching in their current handsets.”

The STPTIC use ParaScan Barium Strontium Titanate (BST) variable-capacitor technology. ST says these devices meet the demands of wireless system designers by displaying high Q factor1 at frequencies up to 2.7 GHz, more than 3:1 capacitance change with varying control voltage, and stable performance over the specified temperature range.

Major features of the STPTIC family:
Range of capacitance values: 2.7 to 8.2 pF
High power capability (+36 dBm)
High tuning range (3.5:1)
High linearity device (IP3 > 60dB)
High Quality factor (Q factor) up to 2.7 GHz
Low leakage current (Less than 100 nA)
Compatible with ST antenna tuning circuit (STHVDAC series)

The STPTIC devices in the 6-pin microDFN and flip-chip packages are sampling now to lead customers direct from ST only, at prices starting at $0.50 and $0.48 respectively for volumes in the range of 1,000 pieces. Alternative pricing options for higher quantities are available on request.