Equivalent series resistance

About: Equivalent series resistance is a research topic. Over the lifetime, 5335 publications have been published within this topic receiving 83362 citations. The topic is also known as: ESR.

The impact of intrinsic series resistance on MOSFET scaling

Abstract: The intrinsic parasitic series resistance associated with the practical structure of a MOSFET is examined. The components considered include contact resistance, diffusion sheet resistance, spreading (injection) resistance, and accumulation layer resistance. The impact of the total resistance on MOSFET scaling is assessed, down to a channel length of 0.15 µm. The results show that, contrary to what has been claimed before, the transconductance and current of a MOSFET continue to increase as the channel length is miniaturized, although the degradation percentage-wise compared to an ideal device without series resistance continues to increase. Based on the degraded I-V characteristics and their effects on an inverter, it is shown here that for NMOS or PMOS digital circuits, the maximum degradation in speed due to series resistance is 20-35 percent compared to ideal scaling for the shortest channel considered. For CMOS circuits, the maximum degradation is reduced to 7-15 percent. In absolute terms, a loss of speed in either case due to miniaturization of channel length is not expected even down to 0.15 µm.

Lossless broad-band monolithic microwave active inductors

Abstract: Lossless broadband microwave active inductors for general-purpose use in microwave circuits are proposed, and their characteristics are discussed. These active inductors are composed of a common-source cascode FET and a feedback FET, and operate in a wide frequency range with very low series resistance. Their low-loss characteristics are demonstrated by simulation and experimental results. A maximum Q factor of 65 is obtained. Theoretically, it can reach infinity. The inductance value can be controlled by an external voltage control. >

Lumped parameter models for single- and multiple-layer inductors

Abstract: A method for modeling inductors under high-frequency operation is presented. The method is based on analytical approaches which can predict turn inductances, turn-to-turn and turn-to-core capacitances using physical structure of windings. Turn inductances, turn-to-turn and turn-to-core capacitances of coils are then introduced into suitable lumped parameter equivalent circuits of inductors. The overall inductance and stray capacitance can be obtained through the use of the equivalent circuits. Both single- and multiple-layer inductors are considered. The method was tested with experimental measurements. The accuracy of the results was good in most cases. The derived expressions can be useful for the design of HF inductors and can also be used for simulation purposes.

Dynamic resistance of a high-Tc superconducting flux pump

Abstract: Superconducting flux pumps enable large currents to be injected into a superconducting circuit, without the requirement for thermally conducting current leads which bridge between the cryogenic environment and room temperature. In this work, we have built and studied a mechanically rotating flux pump which employs a coated conductor high-Tc superconducting (HTS) stator. This flux pump has been used to excite an HTS double pancake coil at 77 K. Operation of the flux pump causes the current within the superconducting circuit to increase over time, before saturating at a limiting value. Interestingly, the superconducting flux pump is found to possess an effective internal resistance, Reff, which varies linearly with frequency, and is two orders of magnitude larger than the measured series resistance of the soldered contacts within the circuit. This internal resistance sets a limit for the maximum achievable output current from the flux pump, which is independent of the operating frequency. We attribute this ...

Electrical, optical and thermal degradation of high power GaN/InGaN light-emitting diodes

Abstract: The degradation of high power GaN/InGaN blue light-emitting diodes (LEDs) was investigated by considering the electrical, optical and thermal ageing characteristics. The LED samples were stressed at the elevated temperature of 85 °C with an injection current of 350 mA. Changes in the tunnelling current and series resistance for the electrical characteristics and an initial increase followed by a gradual decrease for the optical power were observed. Variations of the thermal resistance in the chip and package were found to be 2 °C W−1 and 0.3 °C W−1, respectively. The responsible factors were proposed to be: (a) the dopant activation and changes of defects in the chip level; (b) the yellowing of the optical lens and structural degradations such as generating voids or delaminations in the package level. The changes in the electrical, optical and thermal characteristics were found to depend on and affect each other. The internal relationship for the characteristics of the three aspects was explained.