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A 32-bit direct digital frequency synthesizer with a maximum operating frequency of 4.5 GHz fabricated in 0.25 µm SiGe HBT is presented. The phase-to-amplitude mapping circuit is implemented with nonlinear DAC coarse quantization and ROM-based piecewise linear interpolation. The measured SFDR is between 46 dBc and 60 dBc under a 4.0 GHz clock and the hopping time is less than 10 ns. This chip occupies...
This paper reports a fully differential variable gain amplifier (VGA) using GaAs heterojunction bipolar transistors (HBTs). Gilbert cells with transimpedance loads are applied to achieve wide bandwidth. According to the single-ended measurements, the 3-dB bandwidth is 10.5GHz at a maximum gain of 22dB. A gain-bandwidth product of 132GHz is achieved. The circuit consists of two cascaded variable gain...
In this paper several sub-cell and unit-cell power heterojunction bipolar transistor were fabricated and the impact of device dimension and structure on the device characteristic of sub-cell and unit-cell power HBT Transistor is analyzed and discussed. It was found that: for the sub-cell HBT with different dimension a larger emitter size means smaller RF gain. When the sub-cells were used to form...
This paper presents an ultra-high-speed direct digital frequency synthesizer (DDS) microwave monolithic integrated circuit (MMIC) implemented in 1μm GaAs HBT technology. The DDS has the capabilities of direct frequency modulations with 8-bit frequency resolutions. Utilizing a Double-Edge-Trigger (DET) 8-stage pipeline accumulator with sine-weighted DAC based ROM-less architecture, this DDS MMIC can...
A 64 × 3-bit read-only memory (ROM), employing dual decoder architecture, is designed in GaAs HBT technology. It is adopted in Direct Digital Synthesizer (DDS) for phase-to-amplitude conversion. To enhance the performance of the ROM, the memory cell is designed with a transistor to assign both a high and low bit value. The ROM draws a current of 130 mA from a -4.6 V power supply. Using 700 GaAs HBT...
This paper proposes a new DDS architecture combined with Nonlinear DAC and Wave-Correction-ROM (WCR) which shows both high operating speed and accuracy. Based on this architecture, a 6 GHz 8-bit DDS MMIC is designed and fabricated in 60 GHz GaAs HBT Technology. The DDS MMIC includes 8-bit pipeline accumulator, an 8×8×3 bits WCR, two combined DACs and an analog Gilbert Cell for sine-wave generation...
This paper presents a 10GHz 8-bit Direct Digital Synthesizer (DDS) Microwave Monolithic Integrated Circuit (MMIC) implemented in 1μm GaAs HBT technology. The DDS takes a Double-Edge-Trigger (DET) 8-stage pipeline accumulator with sine-weighted DAC based ROM-less architecture, that can maximize the utilization ratio of GaAs HBT's high-speed potential. With an output frequency up to 5GHz, the DDS gives...
A HBT MIC power amplifier with power combining based on InGaP/GaAs HBT was developed and measured for the application of C-band. The amplifier consists of two 2??480 ??m emitter area InGaP/GaAs HBT power transistors. Microstripe line parallel matching networks were used to divide and combine the power. A parallel RC stabilization network was used to suppress the self-oscillation. By biasing the amplifier...
An InP-based single-heterojunction bipolar transistor (SHBT) with base mu-bridge and emitter air-bridge is reported in this paper. Because those bridges reduce parasite greatly, cutoff frequency fT of the 2 times 12.5 mum2 InP SHBT without de-embedding reaches 178GHz. Such device can output more power than traditional structure HBT with the same fT because of wider emitter. And it is critical to...
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