A Buffer Amplifier for Active Probes of Oscilloscope
Date Issued
2015
Date
2015
Author(s)
Liao, Chun-Yu
Abstract
As the extremely rapid development of electronic industry, the demand for measurement equipment and it’s related commercial value obviously increase year by year. However, most measurement equipment in the market is made by foreign manufacturers, such as Agilent and Tektronix Technology. In order to enhance the competitiveness of domestic measurement instruments industries, we must develop our own technologies and system in this field. Above all, the two crucial specifications which impact the price and margin of digital oscilloscope are bandwidth and sampling rate. In this thesis, the advantages and disadvantages are analyzed between different probes. Also, a prototype of 10X active probe is proposed. There are two parts in the prototype of active probe, attenuation circuit and buffer amplifier. Using the architecture of super source follower and complementary source follower, the buffer amplifier is demonstrated to achieve wideband and high input voltage range. In the second work, an offset voltage calibration circuit is used to reduce the offset voltage in output at the same time. All of chip designed in this thesis are implemented in 0.18 m 1P6M CMOS process.The measured -3dB bandwidth can achieve 2.7 GHz and the input voltage range from -1 V to 6 V in the first work. The chip size is 261 um x 279 um. In the second work, the measurement results show that the active probe system bandwidth achieve 1.7 GHz, and the input voltage range from 0.5 V to 5 V. The chip size is 570 um x 370 um.
Subjects
Active Probe
Super Source Follower
Complementary Source Follower
CMOS
Oscilloscope
Type
thesis