A 700 pJ/bit, 2.4 GHz, narrowband, PLL-free burst mode transmitter based on an FBAR with 5&amp;#x03BC;s startup time for highly duty-cycled systems

Thirunarayanan, Raghavasimhan; Ruffieux, David; Pengg, F.; Scolari, Nicola; Persechini, P.; Enz, Christian

doi:10.1109/rfic.2014.6851648

Cited by 7 publications

(2 citation statements)

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“…Such an architecture would also avoid the settling time latency of the PLL, which is an added advantage. Based on the above idea, a PLL-free TX based on a film-bulk acoustic wave resonator (FBAR) was presented in [7] that has an advantage of greatly reducing the energy overhead. This paper expands on this by detailing the impact of this PLL-free TX on duty-cycled systems, as well as providing further details about the design of this TX.…”

Section: Introductionmentioning

confidence: 99%

Reducing Energy Dissipation in ULP Systems: PLL-Free FBAR-Based Fast Startup Transmitters

Thirunarayanan

Ruffieux

Enz

2015

IEEE Trans. Microwave Theory Techn.

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The energy dissipated by conventional phase-lockedloop-based transmitters (TXs) during the long startup phase is a major bottleneck that reduces the energy autonomy of duty-cycled ultra-low-power systems. In order to tackle this problem, this paper presents a loop-free TX based on a film-bulk acoustic wave resonator (FBAR) that has a 5-s startup time and requires just 3-s for channel switching. The presented TX takes advantage of the high-frequency stability of the FBAR digitally controlled oscillator (DCO) to operate in open loop mode. In order to avoid the problem of the same frequency stability that also hinders addressing multiple channels, the DCO output is mixed with a divided down version (which gives the IF) of itself. By adjusting the division ratio suitably, frequency of the system can then be tuned. To further relax the tuning requirements on the FBAR, the divider for producing the IF is implemented as a phase-switching divider with a step size of 0.2. Integrated in a 65-nm technology node, the TX can address all the bands within the 2.36-2.5-GHz frequency range viz. Medical body area network, industrial, scientific, and medical, and low-power active medical implant bands. Moreover, this TX is able to reach up to 16-Mb/s peak data rate while consuming 9.2 mA at 1.2 V.Index Terms-Film-bulk acoustic wave resonator (FBAR), phase-locked loop (PLL)-free transmitter (TX), phase-switching divider (PSD), quantization noise (QN), ultra-low-power (ULP) systems.

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Section: Introductionmentioning

confidence: 99%

Reducing Energy Dissipation in ULP Systems: PLL-Free FBAR-Based Fast Startup Transmitters

Thirunarayanan

Ruffieux

Enz

2015

IEEE Trans. Microwave Theory Techn.

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“…The use of an FBAR based PLL-free architecture helps to increase the P DR immensely due to the inherent low phase noise of the FBAR. Indeed, the maximum data rate achieved in the case of the TX presented in this paper is 16 Mbps [2] which is much higher than the State-of-the-Art (SOTA) [1]. The FBAR, due to its low phase noise, is also used in the RX for enabling a low power, channel selection lattice filter at RF [3].…”

Section: Introductionmentioning

confidence: 99%

Enabling highly energy efficient WSN through PLL-free, fast wakeup radios

Thirunarayanan

Ruffieux

Enz

2015

2015 IEEE International Symposium on Circuits and Systems (ISCAS)

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Energy wasted during the wake-up of radios significantly degrades the efficiency of duty-cycled Wireless Sensor Networks (WSN). The major contributor to this energy wastage is the PLL-based frequency synthesizer which has a long wakeup time. Furthermore, the rate of duty cycling in these radios is also constrained by the PLL which imposes an upper limit on the maximum data rate that can be achieved by the radio. In order to improve upon both these bottlenecks, this paper presents an overview of highly agile, PLL-free radios based on FBAR DCOs. These synthesizers have the advantage of a 5µs wakeup, thereby reducing the energy wastage. In addition, they also support high-data rates (upto 16 Mbps) thereby increasing the rate of duty cycling which also improves the energy efficiency. The extremely low phase noise of the FBAR is an added advantage that has been leveraged to provide a low power channel selection filter for a sub-sampling receiver architecture. Index Terms -WSN; FBAR; PLL-free Radios; fast wakeup.978-1-4799-8391-9/15/$31.00 ©2015 IEEE

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