Browsing by Author "Tseng, SC"

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4.9-GHz low-phase-noise transformer-based superharmonic-coupled GaInP/GaAs HBT QVCO
(2006-06-01)
Meng, CC
;
Chang, YW
;
Tseng, SC
;
資訊工程學系
;
Department of Computer Science
The low-phase-noise GaInP/GaAs heterojunction bipolar transistor (HBT) quadrature voltage controlled-oscillator (QVCO) using transformer-based superharmonic coupling topology is demonstrated for the first time. The fully integrated QVCO at 4.87 GHz has phase noise of -131 dBc/Hz at 1-MHz offset frequency, output power of -4 dBm and the figure of merit (FOM) -198 dBc/Hz. The state-of-the-art phase noise FOM is attributed to the superior GaInP/GaAs HBT low-frequency device noise and the high quality transformer formed on the GaAs semi-insulating substrate.
A modified HICUM model for GaInP/GaAs HBT devices
(2006-04-01)
Tseng, SC
;
Meng, CC
;
Chen, WY
;
Su, JY
;
電信工程研究所
A compact physics-based transit-time model is established for the GaInP/GaAs HBT device. The VBIC model fails to describe the transit-time frequency versus bias (I-C, V-CE), especially at low- and medium-current regimes. Starting with the HICUM model, we introduce a new time constant to describe the transit-time frequency versus bias (I-C, V-CE) more precisely. This model has obvious advantages over the VBIC model for showing the relation oj'f, versus bias (I-C, V-CE) in the low and medium current regimes for GaInP/GaAs HBT devices. (c) 2006 Wiley Periodicals, Inc.
Determining GaInP/GaAs HBT device structure by DC measurements on a two-emitter HBT device and high frequency transit time measurements
(2005-06-01)
Meng, CC
;
Tsou, BC
;
Tseng, SC
;
電信工程研究所
;
Institute of Communications Engineering
A method to monitor the GaInP/GaAs HBT device structure including emitter ledge thickness is demonstrated in this paper. The base thickness and base doping density are obtained through base transit time and base sheet resistance measurements while the base transit time is measured through the cut-off frequency measurements at various bias points. A large size two-emitter HBT device is used to measure the ledge thickness. Emitter doping profile and collector doping profile are obtained by the large size HBT device through C-V measurements. An FATFET device formed by two emitters as drain and source terminals and the interconnect metal as the on-ledge Schottky gate between two emitters is used to measure the ledge thickness.
The port-to-port isolation of the downconversion P-type micromixer using different N-well topologies
(2006-04-01)
Tseng, SC
;
Meng, CC
;
Li, YH
;
Huang, GW
;
電信工程研究所
The port-to-port isolation of the micromixer is studied using three different p-type downconversion micromixers in 0.35-mu m CMOS technology. Both the body effect and the well isolation influence the port-to-port isolation significantly. The body effect degrades the LO-to-RF isolation and also deteriorates the LO-to-RF isolation. Without the well isolation, the LO-to-RF isolation drops. However, the RF-to-IF isolation is independent of the body effect and well isolation. The p-type micromixer with a separate N-well and without body effect has the best port-to-port isolation properties; its LO-to-IF, LO-to-RF, and RF-to-IF isolations are -59 dB, -58 dB, and -30 dB, respectively.
True 50% duty-cycle SSH and SHHSiGeBiCMOS divide-by-3 prescalers
(2006-06-01)
Tseng, SC
;
Meng, C
;
Chen, WY
;
電信工程研究所
;
Institute of Communications Engineering
Four 50% duty-cycle divide-by-3 prescalers-positively/negatively triggered sample-sample-hold (SSH) and sample-hold-hold (SHH) prescalers-are designed based on the current switchable D flip-flops and discussed in this paper. The positively triggered SSH and SHH prescalers are fabricated using the 0.35-mu m SiGe BiCMOS technology and measured by the real-time oscilloscope and the spectrum analyzer. The SHH prescaler is our proposed structure and demonstrated in this paper. According to the measurement results, under the condition of the same input power, its maximum operation frequency is twice as high as that of the SSH prescaler thanks to better signal synchronization. At 2.7 V supply, the SSH prescaler operates from 500 MHz to 2 GHz as the SHH prescaler performs from 1 GHz to 3.4 GHz. The input sensitivity level of both structures is about -5 dBm, while the maximum output power is also about -5 dBm. The core current consumption is 4.538 mA and 4.258 mA for the SSH and SHH prescalers, respectively.