A novel resonant circuit consisting of transformer-based switched variable inductors and switched accumulation MOS (AMOS) varactors is proposed to realize an ultrawide tuning range voltage-controlled-oscillator (VCO). The VCO IC is designed and fabricated using 0.11 µm CMOS technology and fully evaluated on-wafer. The VCO exhibits a frequency tuning range as high as 92.6% spanning from 1.20 GHz to 3.27 GHz at an operation voltage of 1.5 V. The measured phase noise of -120 dBc/Hz at 1 MHz offset from the 3.1 GHz carrier is obtained.

Junction leakage current of trench isolation devices is strongly influenced by trench configuration. The origin of the leakage current is the mechanical stress that is generated by the differential thermal expansion between the Si substrate and the SiO2 filled isolation trench during the isolation forming process. A two-dimensional mechanical stress simulation was used to analyze trench-isolated devices. The simulated distribution and magnitude of stress were found to agree with Raman spectroscopic measurements of actual devices. The stress in the deeper regions between deep trenches is likely to increase greatly as the size of devices diminishes, so it is important to reduce this stress and thus suppress junction leakage current.

This paper presents the strategy of MOS varactor's high-Q optimization, a novel scalable model for the quasi-millimeter-wave MOS varactors, and confirmation results by discrete MOS varactors and VCO measurements. To realize a high-Q MOS varactor in the quasi-millimeter-wave region, low MOS varactor capacitance and low series resistance of unit cell are essential. Downsizing is a key to realize both low capacitance and low resistance. However, it is induced by Cmax/Cmin reduction, simultaneously. Therefore, scalable MOS varactor model is necessary to use optimum MOS varactor to cover various application requirements using same process. Decreasing the MOS varactor's size of W/L =2µm/2µm to 0.5µm/0.26µm, the Q factor increased sevenfold at f =20GHz but Cmax/Cmin is reduced by 60%, by using conventional PSP model, an error of approximately 20% is shown. Proposed model has been improved its accuracy from 18.9% to 0.2% for N+ MOS varactor and from 22.1% to 0.8% for P+ MOS varactor, for minimum size of MOS varactor even if model covers wide dimension range. Also, it has been confirmed this model is covered in two types of layouts. Oscillation frequency and phase noise also have been confirmed by three types of 22GHz VCOs. The accuracy of oscillation frequency is less than 2.5% and that of phase noise at 1MHz offset from carrier is less than 5dB.

Fully integrated VCO using the "turbo-charger" technique to improve phase noise characteristics is presented. The phase noise degradation of relatively lower oscillation frequency in tuning range was caused by oscillation amplitude lowering due to large total capacitance. On the other hand, the phase noise degradation of relatively higher frequency in tuning range was caused by excess current noise. A new "turbo-charger" circuit increased operation current to obtain sufficient transconductance of amplifier when oscillation frequency was lower to improve phase noise characteristics. The phase noise of VCO employing this technique was extremely low and stable, below -140-dBc/Hz at 3-MHz offset from oscillation frequency, in wide oscillation frequency range, approximately 200-MHz for 1200-MHz oscillation. This VCO was operated with 5.8-7.4-mA current consumption at 3-V supply voltage. The manufacturing process was 0.6-µm SiGe BiCMOS.

In this work, the metal-oxide-metal (MOM) capacitor in the scaled CMOS process has been modeled at high frequencies using an EM simulator, and its layout has been optimized. The modeled parasitic resistance consists of four components, and the modeled parasitic inductance consists of the comb inductance and many mutual inductances. Each component of the parasitic resistance and inductance show different degrees of dependence on the finger length and on the number of fingers. The substrate network parameters also have optimum points. As such, the geometric dependence of the characteristics of the MOM capacitor is investigated and the optimum layout in the constant-capacitance case is proposed by calculating the results of the model. The proposed MOM capacitor structures for 50fF at f =60GHz are L =5μm with M =3, and, L =2μm with M =5 and that for 100fF at f =30GHz are L =9μm with M =3, and L =4μm with M =5. The target process is 65-nm CMOS.

A 5-GHz-band highly linear frequency tuning voltage-controlled oscillator (VCO) using 0.35 µm SiGe BiCMOS technology is presented. The highly linear VCO has a novel resonant circuit that includes two spiral inductors, p-n junction diode varactor units and a voltage-level- shift circuit. The fabricated VCO exhibits a VCO gain from 224 to 341 MHz/V, giving a Kvco ratio of 1.5, which is less than one-half of that of a conventional VCO. The measured phase noise is -116 dBc/Hz at 1 MHz offset at an oscillation frequency of 5.5 GHz. The tuning range is from 5.45 to 5.95 GHz. The dc current consumption is 3.4 mA at a supply voltage of 3.0 V.

In this paper, a single-chip dual-mode 8-band 130 nm CMOS transceiver including A/D/A converters and digital filters with 312 MHz LVDS interface is presented. For a transmitter chain, linear direct quadrature modulation architecture is introduced for both W-CDMA/HSDPA (High Speed Uplink Packet Access) and for GSM/EDGE. Analog baseband LPFs and quadrature modulators are commonly used both for GSM and for EDGE. For a direct conversion receiver chain, ABB (Analog Base-Band) blocks, i.e., LPFs and VGAs, delta-sigma A/D converters, and FIR filters are commonly used for W-CDMA/HSDPA (High Speed Downlink Packet Access) and GSM/EDGE to reduce chip area. Their characteristics can be reconfigured by register-based control sequence. The receiver chain also includes high-speed DC offset cancellers both in analog and in digital stage, and the self-contained AGC controller, whose parameters such as time constant are programmable to be free from DBB (Digital Base-Band) control. The transceiver also includes wide-range VCOs and fractional PLLs, an LVDS driver and receiver for high-speed digital interface of 312 MHz. Measured results reveal that the transceiver satisfies 3GPP specifications for W-CDMA/HSPA (High Speed Packet Access) and GSM/EDGE.

A 6 GHz integrated VCO using SiGe BiCMOS process has been studied. The integrated inductors were realized by third metal with 3 µm thickness aluminum and its Q=20 at 6 GHz. The amplifier consisted of bipolar transistor. Tuning range was 38% with 0 V to 3 V tuning voltage. Phase noise of -100 dBc/Hz was obtained at 1 MHz offset from carrier frequency. The current consumption of VCO was 4.9 mA at 3 V power supply.

A fully integrated 5.8 GHz ETC transceiver LSI has been developed. The transceiver consists of LNA, down-conversion MIX, ASK detector, ASK modulator, DA VCO, and ΔΣ-fractional-N PLL. The features of the transceiver are integrated matching circuitry for LNA input and for DA output, ASK modulator with VGA for local signal control to avoid local leakage and to keep suitable modulation index, and LO circuitry consisting of ΔΣ-fractional-N PLL and interference-robust ∞-shape inductor VCO to diminish magnetic coupling from any other circuitry. Use of these techniques enabled realization of the input and output VSWR of less than 1.25, modulation index of over 95%, and enough qualified TX signals. This transceiver was manufactured by 1P3M SiGe-BiCMOS process with 47 GHz cut-off frequency.

In this paper, a CMOS Class-G supply modulation for polar power amplifiers with high average efficiency and low ripple noise is proposed. In the proposed Class-G supply modulation, the parallel supply modulations which are controlled by switch signals are utilized for low power and high power supplies to increase the average efficiency. A low dropout (LDO) is utilized to suppress the delta-modulated noise and provide a low ripple noise power supply. The proposed supply modulation has high efficiency at large output current as the conventional supply modulation, and it also has high efficiency and low ripple noise at the low output current. To verify the effectiveness of the proposed supply modulation, the proposed supply modulation was designed with 0.13 µm CMOS process. The simulation results show that the proposed supply modulation achieves a maximum efficiency of 85.1%. It achieves an average efficiency of 29.3% and a 7.1% improvement compared with the conventional supply modulations with Class-E power amplifier. The proposed supply modulation also shows an excellent spurious free dynamic range (SFDR) of -73 dBc for output envelope signal.

This paper presents a single-chip RF tuner/OFDM demodulator for a mobile digital TV application called “1-segment broadcasting.” To achieve required performances for the single-chip receiver, a tunable technique for a low-noise amplifier (LNA) and spurious suppression techniques are proposed in this paper. Firstly, to receive all channels from 470 MHz to 770 MHz and to relax distortion characteristics of following circuit blocks such as an RF variable-gain amplifier and a mixer, a tunable technique for the LNA is proposed. Then, to improve the sensitivity, spurious signal suppression techniques are also proposed. The single-chip receiver using the proposed techniques is fabricated in 90 nm CMOS technology and total die size is 3.26 mm 3.26 mm. Using the tunable LNA and suppressing undesired spurious signals, the sensitivities of less than -98.6 dBm are achieved for all the channels.

A striped inductor and its utilization of a voltage-controlled oscillator (VCO) are studied with the aim of suppressing phase noise degradation in K- and Ka-bands. The proposed striped inductor exhibits reduced series resistance in the high frequency region by increasing the cross-sectional peripheral length, as with the Litz wire, and the VCO of the striped inductor simultaneously exhibits a lower phase noise than that of the conventional inductor. Striped and conventional inductors and VCOs are designed and fabricated, and their use of K- and Ka-bands is measured. Results show that the Q factor and corner frequency of the striped inductor are approximately 1.3 and 1.6 times higher, respectively, than that of the conventional inductor. Moreover, the 1-MHz-offset phase noise of the striped inductor's VCO in the K- and Ka-bands was approximately 3.5 dB lower than that of the conventional inductor. In this study, a 65-nm standard CMOS process was used.

A scalable MOSFET parasitic model has been studied using 0.13 µm standard CMOS process. The model consisted of a core BSIM3v3 transistor model and parasitic resistor, capacitor, inductor, and diode. All parasitic components' values were automatically calculated by transistor geometrical parameters, only gate length (Lg), gate width (Wg), and gate multiple numbers (Mg), and some fixed process parameters such as sheet resistance of each part of diffusion layer. This model was confirmed for 0.25 µm to 0.5 µm gate length, 10 to 40 gate multiples with 5 µm gate finger width (Wf), 0.8 V to 1.5 V gate-source voltage (|Vgs|) with 0.6 V threshold voltage (|Vth|), and 1.0 V to 2.5 V drain-source voltage (|Vds|) from the viewpoint of small signal. The measured s-parameter and simulated one are in fairly good agreement in 200 MHz to 20 GHz frequencies range. This model is very simple, scalable, and convenient for RF circuit designers without difficult parameter setting.

Quadrature voltage-controlled oscillators (VCOs) with current-weight-average and voltage-weight-average phase-adjusting architectures are studied. The phase adjusting equalizes the oscillation frequency to the LC-resonant frequency. The merits of the equalization are explained by using Leeson's phase noise equation and the impulse sensitivity function (ISF). Quadrature VCOs with the phase-adjusting architectures are fabricated using 180-nm TSMC CMOS and show low-phase-noise performances compared to a conventional differential VCO. The ISF analysis and small-signal analysis also show that the drawbacks of the current-weight-average phase-adjusting and voltage-weight-average phase-adjusting architectures are current-source noise effect and large additional capacitance, respectively. A voltage-average-adjusting circuit with a source follower at its input alleviates the capacitance increase.

Integrated 900-MHz ISM band transceiver LSI for analog cordless telephone has been realized by cost-effective process technology with sufficient performance. This LSI consisted of fully integrated transceiver, from RF-LNA to audio amplifier for RX chain, from microphone's amplifier to RF-PA for TX chain, and integrated RX- and TX-LO consisting of PLLs and VCOs. In view of narrow signal bandwidth with analog modulation, extremely low phase noise at low offset frequency from carrier was required for integrated VCO. Also, in view of fully duplex operations, signal isolation between TX and RX was required. Despite such a high integration and high performance, chip cost had to be minimized for low-cost applications. The 12-dB SINAD RX sensitivity was -111.2 dBm, the output power of TX was +3 dBm, and the phase noise of integrated VCO was -77 dBc/Hz at 3 kHz offset away from carrier. The current consumption at fully duplex operation was 76 mA at 3.6 V power supply. The chip was realized by 0.8 µm standard silicon BiCMOS process.

A 2.4 GHz 0.13 µm CMOS transceiver LSI, supporting Bluetooth V2.1+enhanced data rate (EDR) standard, has achieved a high reception sensitivity and high-quality transmission signals between -40 and +90. A low-IF receiver and direct-conversion transmitter architecture are employed. A temperature compensated receiver chain including a low-noise amplifier accomplishes a sensitivity of -90 dBm at frequency shift keying modulation even in the worst environmental condition. Design optimization of phase noise in a local oscillator and linearity of a power amplifier improves transmission signals and enables them to meet Bluetooth radio specifications. Fabrication in scaled 0.13 µm CMOS and operation at a low supply voltage of 1.5 V result in small area and low power consumption.

The low phase noise, low supply voltage 1.3 GHz CMOS VCO has been realized by 0.25 µm standard CMOS technology without any trimming and any tuning. The phase noise characteristics of -109 dBc/Hz and -123 dBc/Hz at 100 kHz offset and 500 kHz offset were achieved from carrier, respectively, with 1.3 GHz oscillation frequency at 1.4 V supply voltage. The performance of 1.4 V supply voltage phase noise was superior to that of 2.0 V supply voltage phase noise due to low output impedance current source. The tuning ranges of 13.3%, 16.6%, and 20.1% for 1.4 V, 1.8 V, and 2.0 V supply voltage were achieved, respectively. The amplifier consisted of one pair of PMOS differential stage with large gate length NMOS current source to realize low supply voltage operation and to avoid flicker noise contribution for phase noise. The on-chip spiral inductor consisted of three terminals arranged in a special shape to obtain high Q and small chip area. The power dissipation of this VCO was 22.4 mW without buffer amplifier.