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Full-Text Articles in Electronic Devices and Semiconductor Manufacturing
Limiters Protect Adcs Without Adding Harmonics, Chin-Leong Lim
Limiters Protect Adcs Without Adding Harmonics, Chin-Leong Lim
Chin-Leong Lim
High-speed Analogue to Digital Converters (ADC) are used for sampling at either the intermediate frequency (IF) or the radio frequency of wireless receivers. When the transmitter is nearby, the sampled signal can exceed the ADC’s maximum input level. So, amplitude limiting is necessary to prevent ADC damage or degradation. While automatic gain control is effective for controlling IF amplitude excursion in traditional single-carrier systems, it is not desirable in modern multi-carrier applications. One solution is to cap the IF amplitude excursion with a limiter. Unfortunately, a new problem is created – the strong non-linearity that is required of a good …
Low Loss Configuration For Integrated Pin-Schottky Limiters, Chin-Leong Lim
Low Loss Configuration For Integrated Pin-Schottky Limiters, Chin-Leong Lim
Chin-Leong Lim
Compared to the PIN diode limiter, the Schottky-PIN limiter improves receiver protection, but has a higher insertion loss. Low cost, plastic packaged diodes can further worsen the loss. Diode stacking, mesa diode construction, and isolating the Schottky diode with a high-impedance quarter wave line or a directional coupler can reduce loss, but detrimentally raises the limiting threshold and/or adds bulk or cost. The PIN-Schottky limiter’s insertion loss can be improved by integrating the diodes’ parasitic capacitances into a low pass ladder network, but this solution requires the PIN diode to have two anode connections. Recently, the PIN-Schottky limiter was integrated …
Limiting And Transient Performances Of A Low Loss Pin-Schottky Limiter, Chin-Leong Lim
Limiting And Transient Performances Of A Low Loss Pin-Schottky Limiter, Chin-Leong Lim
Chin-Leong Lim
The main cause of loss in the PIN-Schottky limiter is the diodes’ parasitic capacitances. Techniques to counter the parasitic capacitances include using bare chip, air cavity packaging, diode stacking, mesa construction, isolating the Schottky diode from the signal path and connecting the diodes to a low impedance node. But the aforementioned techniques either sacrifice cost, manufacturability, size, performances or thermal ruggedness. To reduce loss in the PIN-Schottky limiter, we re-configured its parasitics into a low pass ladder network. This paper reports on the new configuration’s changed large signal and transient performances. We observed improved isolation at 0.9 and 2.4 GHz, …
Recovery Time Of The Schottky-Pin Limiter, Chin-Leong Lim
Recovery Time Of The Schottky-Pin Limiter, Chin-Leong Lim
Chin-Leong Lim
The Schottky-PIN limiter has a ~8dB lower limiting threshold than the self-biased PIN limiter. Following the cessation of overdrive, the limiter requires some time to return to a low-loss state. This transitory state, which is known as the recovery time or blind/dead time, disrupts communication and causes information loss. Unlike the self-biased PIN limiter, there is a dearth of information pertaining to the recovery time of the PIN-Schottky limiter. This work characterizes the most popular form of the PIN-Schottky limiter and also proposes a simple modification to speed up its recovery time. We measured recovery times of >2000uS and 130uS …
Reduce Losses In Rf Schottky-Pin Limiter Circuits, Chin-Leong Lim
Reduce Losses In Rf Schottky-Pin Limiter Circuits, Chin-Leong Lim
Chin-Leong Lim
Limiters can protect wireless receivers from physical damage and information loss. The Schottky-PIN limiter is especially protective because its limiting threshold is ~10dB lower than that of the self-biased PIN limiter. Unfortunately, the limiter diodes have parasitic capacitances that create insertion loss. Moreover, the extra diode in the Schottky-PIN limiter increases its loss over that of the PIN diode-only limiter. Techniques to minimize the parasitic capacitances include using bare chip, air cavity packaging, diode stacking, mesa construction, isolating the Schottky diode from the signal path and connecting the diodes to a low impedance node. But the aforementioned techniques either sacrifice …
Wideband Limiter Fits Sot-323 Pack, Chin-Leong Lim
Wideband Limiter Fits Sot-323 Pack, Chin-Leong Lim
Chin-Leong Lim
Limiters protect wireless receiver front-ends from damage due to signal overload. The Schottky-PIN limiter is more protective than the self-biased PIN limiter because the former's limiting threshold is ~10 dB lower. Present implementation of the Schottky-PIN limiter use separate PIN and Schottky diodes. Additionally, some prior knowledge is necessary to select the correct PIN and Schottky diodes for limiter service. To miniaturize the limiter and to simplify the diode selection process, we combined a pair of limiter-optimized PIN and Schottky diodes into a compact and low-cost SOT-323 package. This paper describes the design, fabrication and experimental validation of the industry's …
Rf Applications Of Pin Diodes, Chin-Leong Lim
Rf Applications Of Pin Diodes, Chin-Leong Lim
Chin-Leong Lim
PIN diodes are the ubiquitous "nuts & screws" components that hold together RF equipment as varied as the television, radio, 2-way radios, WLAN equipment etc. This talk covers PIN diode characteristics and RF applications such as switches, attenuators and limiters. Performance improvement techniques will also be discussed.