This paper presents a digitally controlled frequency generator for dual frequency-band radar system that is optimized for 16 nm FinFET CMOS. It is based on a 21% wide tuning range,fine-resolution DCO with only switchable metal capacitors. A third-harmonic boosting DCO simultaneously generates 22.5-28 GHz and sufficiently strong 68-84 GHz signals to satisfy short-range radar (SRR) and medium/long range radar (M/LRR) requirements. The 20.2 mW DCO emits -97 dBc/Hz at 1 MHz offset from 77 GHz,while fully satisfying metal density rules. It occupies 0.07 mm²,thus demonstrating both 43% power and 47% area reductions. The phase noise and FoM_T (figure-of-merit with tuning range) are improved by 1.8 dB and 0.2 dB,respectively,compared to state-of-the-art.

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We propose a time-predictive architecture of an all-digital PLL (ADPLL) for cellular radios, which is optimized for advanced CMOS. It is based on a 1/8-length time-to-digital converter (TDC) of stabilized 7-ps resolution, as well as wide tuning range, and fine-resolution class-F digitally controlled oscillator (DCO) with only switchable metal capacitors. The 0.4-mW TDC clocked at 40 MHz maintains 7-ps resolution for <-107 dBc/Hz in-band phase noise while the 7.3-mW DCO emits -157 dBc/Hz at 20 MHz offset at 2 GHz. Reference spurs are <-91 dBc, while fractional spurs are <-55 dBc. The ADPLL supports a 2-point modulation and consumes 11.5-mW while occupying 0.22 mm$^2$. @en

This paper proposes an ultra-low-voltage (ULV) fractional-N all-digital PLL (ADPLL) powered from a single 0.5-V supply. While its digitally controlled oscillator (DCO) runs directly at 0.5 V, an internal switched-capacitor dc-dc converter ``doubles'' the supply voltage to all the digital circuitry and particularly regulates the time-to-digital converter (TDC) supply to stabilize its resolution, thus maintaining fixed in-band phase noise (PN) across process, voltage, and temperature (PVT). The ADPLL supports a two-point modulation and forms a Bluetooth low-energy (BLE) transmitter realized in 28-nm CMOS. It maintains in-band PN of -106 dBc/Hz [figure of merit (FoM) of -239.2 dB] and rms jitter of 0.86 ps while dissipating only 1.6 mW at 40-MHz reference. The power consumption reduces to 0.8 mW during the BLE transmission when the DCO switches to open loop.

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In this paper, we investigate an impact of voltage supply scaling on power consumption and performance of a new class of wireless receivers (RX) for Internet-of-Things (IoT) applications: a discrete-time (DT) superheterodyne architecture realized in nanoscale CMOS using inverter-based gm and switched capacitors. The power supply is partitioned into three separate domains: RF, intermediate frequency (IF) processing, and clocking, which allows them to be independently regulated to assess their respective impact. The DT-RX maintains its functionality, albeit with some acceptable loss of performance, when the core supplies are varied by as much as an octave, i.e., from the nominal 1.1 V down to 0.55V. The DT-RX IC is then connected to a switched-capacitor based voltage doubler array on a companion IC die such that the DT-RX can be powered at the octave range of 0.275-0.55 V from an energy harvester. The sensitivity at the doubler's 0.275/0.55 V input is -85/-95 dBm while consuming 1.0/2.4mW. Both ICs are implemented in TSMC 28-nm LP CMOS.

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We present an ultra-low-power Bluetooth low-energy (BLE) transceiver (TRX) for the Internet of Things (IoT) optimized for digital 28-nm CMOS. A transmitter (TX) employs an all-digital phase-locked loop (ADPLL) with a switched current-source digitally controlled oscillator (DCO) featuring low frequency pushing, and class-E/F₂ digital power amplifier (PA), featuring high efficiency. Low 1/ f DCO noise allows the ADPLL to shut down after acquiring lock. The receiver operates in discrete time at high sampling rate (10 Gsamples/s) with intermediate frequency placed beyond 1/ f noise corner of MOS devices. New multistage multirate charge-sharing bandpass filters are adapted to achieve high out-of-band linearity, low noise, and low power consumption. An integrated on-chip matching network serves to both PA and low-noise transconductance amplifier, thus allowing a 1-pin direct antenna connection with no external band-selection filters. The TRX consumes 2.75 mW on the RX side and 3.7 mW on the TX side when delivering 0 dBm in BLE.

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We present an ultra-low-power Bluetooth Low Energy (BLE) transceiver for Internet of things (IoT) optimized for 28-nm CMOS. A transmitter (TX) employs an all-digital phase-locked loop (ADPLL) with switched current source digitally controlled oscillator (DCO) and class-E/F2 power amplifier. The proposed oscillator combines the benefits of low-supply voltage operation of conventional NMOS cross-coupled oscillators with high current efficiency of the complementary push-pull oscillators. It also reduces 1/f noise and supply pushing, thus allowing the ADPLL, after settling, to reduce its sampling rate or shut it off entirely during a direct DCO modulation. The switching power amplifier operates in class-E/F2 to maximally enhance its efficiency at low output power. The receiver (RX) operates in discrete time (DT) at high sampling rate ( ∼ 10 GSample/sec) with an intermediate frequency (IF) placed beyond 1/f noise corner of MOS devices. Multistage multi-rate charge-sharing (CS) band-pass filters (BPF) are placed to achieve high out-of-band linearity, low noise, and low power consumption. Furthermore, an integrated on-chip matching network serves both PA and LNTA, thus allowing a one-pin direct antenna connection with no extra band selection filters. The transceiver consumes 2.75 mW in RX and 3.7 mW in TX when delivering 0 dBm in BLE.@en

This paper introduces a system-level approach to develop the first-ever fully discrete-time (DT) superheterodyne receiver (RX) for Internet-of-Things applications, such as Bluetooth low energy (BLE). It exploits fast switching speed and low internal capacitances of deep-nanoscale CMOS devices to realize a high intermediate-frequency (IF) architecture based on switched-capacitor-based charge-domain bandpass filtering. Power consumption is minimized by aggressively reducing the size of MOS devices and judiciously applying a sampling-rate decimation. The resultant increase in the flicker noise is mitigated by placing the IF frequency beyond the flicker corner frequency. Likewise, the decimation-induced aliasing is mitigated by DT filtering of preceding stages. The BLE RX is fully standard-compliant and achieves a record-low-power consumption of 2.75 mW (including its local oscillator) while delivering the state-of-the-art performance: 6.5-dB noise figure and -19-dBm third-order input intercept point, with a direct antenna connection and thus without the typical external bandpass filters.

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This paper proposes an ultra-low-voltage (ULV) fractional-N all-digital PLL (ADPLL) powered from a single 0.5 V supply. While its DCO runs directly at 0.5 V, a switched-capacitor DC-DC converter doubles the supply voltage to all the digital circuitry and regulates the TDC supply to stabilize its resolution thus maintaining fixed inband phase noise (PN) across PVT. The ADPLL supports a 2-point modulation and forms a Bluetooth LE (BLE) transmitter realized in 28 nm CMOS. It achieves in-band PN of -106 dBc/Hz (FoM of -239.2 dB) and RMS jitter of 0.86ps while dissipating only 1.6mW at 40 MHz reference. The power consumption reduces to 0.8 mW during BLE transmission when the DCO switches to open-loop.
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We propose a new transmitter architecture for ultra-low power radios in which the most energy-hungry RF circuits operate at a supply just above a threshold voltage of CMOS transistors. An all-digital PLL employs a digitally controlled oscillator with switching current sources to reduce supply voltage and power without sacrificing its startup margin. It also reduces 1/f noise and supply pushing, thus allowing the ADPLL, after settling, to reduce its sampling rate or shut it off entirely during a direct DCO data modulation. The switching power amplifier integrates its matching network while operating in class-E/F2 to maximally enhance its efficiency at low voltage. The transmitter is realized in 28 nm digital CMOS and satisfies all metal density and other manufacturing rules. It consumes 3.6 mW/5.5 mW while delivering 0 dBm/3 dBm RF power in Bluetooth Low-Energy mode.@en

We present a new ultra-low-power (ULP) transceiver for Internet-of-Things (IoT) optimized for 28-nm CMOS. The receiver (RX) employs a high-rate (up to 10 GS/s) discrete-time (DT) architecture with intermediate frequency (IF) placed beyond the 1/f noise corner of MOS devices. New multistage multi-rate charge-sharing bandpass filters are adapted to achieve high out-of-band linearity, low noise and low power consumption. A transmitter (TX) employs an all-digital PLL (ADPLL) with switched-current-source digitally controlled oscillator (DCO) and switching PA. An integrated on-chip matching network serves both PA and LNTA, thus allowing a 1-pin direct antenna connection with no external antenna filters. The transceiver consumes 2.75mW in RX and 3.6mW in TX when delivering 0 dBm in Bluetooth LE.@en