Huang Beiju

1-Gb/s zero-pole cancellation CMOS transimpedance amplifier for Gigabit Ethernet applications

A zero-pole cancellation transimpedance amplifier (TIA) has been realized in 0.35 μm RF CMOS tech nology for Gigabit Ethernet applications. The TIA exploits a zero-pole cancellation configuration to isolate the input parasitic capacitance including photodiode capacitance from bandwidth deterioration. Simulation results show that the proposed TIA has a bandwidth of 1.9 GHz and a transimpedance gain of 65 dB·Ω for 1.5 pF photodiode capaci tance, with a gain-bandwidth product of 3.4 THz·Ω. Even with 2 pF photodiode capacitance, the bandwidth exhibits a decline of only 300 MHz, confirming the mechanism of the zero-pole cancellation configuration. The input resis tance is 50 Ω, and the average input noise current spectral density is 9.7 pA/(Hz)~(1/2). Testing results shows that the eye diagram at 1 Gb/s is wide open. The chip dissipates 17 mW under a single 3.3 V supply.

Silicon light emitting device in CMOS technology

A novel silicon light emitting device was realized with standard 0.35 µm 2P4M Mixed Mode/RF CMOS technology. The device functions in a reverse breakdown mode and can be turned on at 8.3 V and operated normally at a wide voltage range of 8.3 V-12.0 V. An output optical power of 13.6 nW was measured at the bias of 10 V and 100 mA, and the emitted light intensity was calculated to be more than 1 mW/cm2. The optical spectrum of the device is in the range of 500–820 nm.

Low power CMOS preamplifier for neural recording applications

A fully-differential bandpass CMOS (complementary metal oxide semiconductor) preamplifier for extracellular neural recording is presented. The capacitive-coupled and capacitive-feedback topology is adopted. The preamplifier has a midband gain of 20.4 dB and a DC gain of 0. The −3 dB upper cut-off frequency of the preamplifier is 6.7 kHz. The lower cut-off frequency can be adjusted for amplifying the field or action potentials located in different bands. It has an input-referred noise of 8.2 μVrms integrated from 0.15 Hz to 6.7 kHz for recording the local field potentials and the mixed neural spikes with a power dissipation of 23.1 μW from a 3.3 V supply. A bandgap reference circuitry is also designed for providing the biasing voltage and current. The 0.22 mm2 prototype chip, including the preamplifier and its biasing circuitry, is fabricated in the 0.35-μm N-well CMOS 2P4M process.

A flexible logic circuit based on a MOS-NDR transistor in standard CMOS technology

A MOS-NDR (negative differential resistance) transistor which is composed of four n-channel metal–oxide–semiconductor field effect transistors (nMOSFETs) is fabricated in standard 0.35 μm CMOS technology. This device exhibits NDR similar to conventional NDR devices such as the compound material based RTD (resonant tunneling diode) in current–voltage characteristics. At the same time it can realize a modulation effect by the third terminal. Based on the MOS-NDR transistor, a flexible logic circuit is realized in this work, which can transfer from the NAND gate to the NOR gate by suitably changing the threshold voltage of the MOS-NDR transistor. It turns out that MOS-NDR based circuits have the advantages of improved circuit compaction and reduced process complexity due to using the standard IC design and fabrication procedure.

A Low-Voltage Silicon Light Emitting Device in Standard Salicide CMOS Technology

A silicon-based field emission light emitting diode for low-voltage operation is fabricated in the standard 0.35 μm 2P4M salicide complementary metal-oxide-semiconductor (CMOS) technology. Partially overlapping p+ and n+ regions with a salicide block layer are employed in this device to constitute a heavily doped p+-n+ junction which has soft “knee Zener breakdown characteristics, thus its working voltage can be reduced preferably below 5 V, and at the same time the power efficiency is improved. The spectra of this device are spread over 500 nm to 1000 nm with the main peak at about 722 nm and an obvious red shift of the spectra peak is observed with the increasing current through the device. During the emission process, field emission rather than avalanche process plays a major role. Differences between low-voltage Zener breakdown emission and high-voltage avalanche breakdown emission performance are observed and compared.