The emerging concept of multistandard radios calls for low-noise amplifier (LNA) solutions able to comply with their needs. Meanwhile, the increasing cost of scaled CMOS pushes towards low-area solutions in standard, digital CMOS. Feedback LNAs are able to meet both demands. This paper is devoted to the design of low-area active-feedback LNAs. We discuss the design of wideband, narrowband and multiband implementations. We demonstrate that competitive RF performance is achievable thanks to CMOS downscaling, pleasing many applications because of their low cost (digital CMOS) and low area (bondpad size).

Severe Fermi level pinning at the interface between $n\text{-}\mathrm{Ge}$ and a metal leads to the formation of a Schottky barrier, almost independent on the metal work function. Therefore, it seems impossible to form metal Ohmic contacts on moderately, $n$ -type doped Ge layers. For $p$ -type Ge, the Fermi level pinning works opposite: all metal contacts show Ohmic behavior. This fixed behavior can be altered by the introduction of a thin ${\mathrm{Ge}}_3{\mathrm{N}}_4$ layer. ${\mathrm{Ge}}_3{\mathrm{N}}_4$ seems effective in reducing Fermi level pinning and, therefore, allows the formation of Ohmic contacts on $n$ -type Ge and a rectifying contact on $p$ -type Ge.

The transmission properties of semiconductor surfaces can be changed by surface texturing. We investigate these changes experimentally and find that an enhancement of the angle-averaged transmission by a factor of 2 can be achieved with optimum texturing parameters. This enhanced transmission provides an additional light extraction mechanism for high-efficiency surface-textured light-emitting diodes. External quantum efficiencies of 46% and 54% are demonstrated before and after encapsulation, respectively.

A 5 bit 1.75 GS/s ADC using a factor 2 dynamic folding technique is presented. The 2X folding lowers the number of comparators from 31 to 16, simplifies encoding and reduces power consumption and area. The comparators in this converter are implemented with built-in references and calibration to further reduce power consumption. INL and DNL after calibration are smaller than 0.3 LSB, with an SNDR of 29.9 dB at low frequencies, and above 27.5 dB up to the Nyquist frequency. The converter consumes 2.2 mW from a 1 V supply, yielding a FoM of 50 fJ per conversion step and occupies 0.02 mm² in a 90 nm 1P9M digital CMOS process.

A 60 GHz sub-sampling PLL implemented in 40 nm CMOS is presented in this paper. The sub-sampling phase detector (SSPD) runs at 30 GHz after an inductively-peaked static divide-by-two. Thanks to the lower frequency of operation, the effect of non-zero sampling aperture of the switch is minimized. A dummy divider of the quadrature PLL is utilized for the sub-sampling loop to avoid extra loading in the 60 GHz path. A 53.8-63.3 GHz QVCO uses super-harmonic coupling at 120 GHz for relaxed headroom at a 0.9 V supply and achieves a free-running phase noise down to -94.5 dBc/Hz at 1 MHz offset. The millimeter-wave sub-sampling PLL achieves an RMS jitter, integrated from 1 kHz to 100 MHz, of 200 fs at a power consumption of 42 mW, compared to 210 fs for the PFD/CP PLL at 75 mW. Reference spurs in both modes are below -40 dBc.

The dynamic behavior of high-efficiency light-emitting diodes (LEDs) is investigated theoretically and experimentally. A detailed theoretical description of the switch-on and switch-off transients of LEDs is derived. In the limit of small-signal modulation, the well-established exponential behavior is obtained. However, in the case of high injection, which is easily reached for thin active layer LEDs, the small-signal time constant is found to be up to a factor of two faster than the radiative recombination lifetime. Using such quantum-well LEDs, we have demonstrated optical data transfer with wide open eye diagrams at bit rates up to 2 Gbit/s. In addition, we have combined the use of thin active layers with the concept of surface-textured thin-film LEDs, which allow a significant improvement in the light extraction efficiency. With LEDs operating at 0.5 Gbit/s and 1 Gbit/s, we have achieved external quantum efficiencies of 36% and 29%, respectively.