METHOD AND APPARATUS FOR USE IN DIGITALLY TUNING A CAPACITOR IN AN INTEGRATED CIRCUIT DEVICE

• Main Author: RANTA, Tero Tapio
• Format: Patent
• Language: English; French; German
• Published: 31.01.2024
• Subjects: BASIC ELECTRONIC CIRCUITRY; CODE CONVERSION IN GENERAL; CODING; DECODING; ELECTRICITY; PULSE TECHNIQUE

A method and apparatus for use in a digitally tuning a capacitor in an integrated circuit device is described. A Digitally Tuned Capacitor DTC is described which facilitates digitally controlling capacitance applied between a first and second terminal. In some embodiments, the first terminal comprises an RF+ terminal and the second terminal comprises an RF- terminal. In accordance with some embodiments, the DTCs comprise a plurality of sub-circuits ordered in significance from least significant bit (LSB) to most significant bit (MSB) sub-circuits, wherein the plurality of significant bit sub-circuits are coupled together in parallel, and wherein each sub-circuit has a first node coupled to the first RF terminal, and a second node coupled to the second RF terminal. The DTCs further include an input means for receiving a digital control word, wherein the digital control word comprises bits that are similarly ordered in significance from an LSB to an MSB. Each significant bit of the digital control word is coupled to corresponding and associated significant bit sub-circuits of the DTC, and thereby controls switching operation of the associated sub-circuit. DTCs are implemented using unit cells, wherein the LSB sub-circuit comprises a single unit cell. Next significant bit sub-circuits comprise x instantiations of the number of unit cells used to implement its associated and corresponding previous significant bit sub-circuit, wherein the value x is dependent upon a weighting coding used to weight the significant bit sub-circuits of the DTC. DTCs may be weighted in accordance with a binary code, thermometer code, a combination of the two, or any other convenient and useful code. In many embodiments, the unit cell comprises a plurality of stacked FETs in series with a capacitor. The unit cell may also include a plurality of gate resistors RG coupled to the gates of the stacked FETs, and a plurality of RDS resistors coupled across the drain and source of the stacked FETs. The stacked FETs improve the power handling capabilities of the DTC, allowing it meet or exceed high power handling requirements imposed by current and future communication standards.