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A novel diode-connected MOS transistor for ultra-high-frequency (UHF) micro-power rectifiers was presented, and a high efficiency N-stage charge pump voltage rectifier based on this new diode-connected MOS transistor was designed and implemented. The new diode-connected MOS transistor and the rectifier are designed and fabricated in SMIC [email protected] 2P3M CMOS embedded EEPROM process. The structure design of the new diode achieved 315mV turn-on voltage, and 415nA reverse saturation leakage current. Compared with traditional rectifier, the rectifier using the presented diode-connected MOS has higher power conversion efficiency (PCE), higher output voltage and smaller ripple coefficient. When the RF input is a 900-MHz sinusoid signal with the amplitude ranging from 0.8 to 1.8V, PCEs of the charge pump rectifier with only 3-stage are more than 30%, and the maximum output voltage is 5.02V, and its ripple coefficients are less than 1%.

A novel current reference based on subthreshold MOSFETs with high power supply rejection ratio (PSRR) is presented. The proposed circuit takes full advantages of the I-V transconductance characteristics of MOSFET operating in the subthreshold region and the enhancement pre-regulator with the high gain negative feedback loop for the current reference core circuit. The proposed circuit, designed with the SMIC [email protected] standard CMOS logic process technology, exhibits a stable current of about [email protected] with much low temperature coefficient of 2.5x10^-^[email protected]/^oC in the temperature range of -40 to 150^oC at 1.5V supply voltage, and also achieves a best PSRR over a broad frequency. The PSRR is about -126dB at dc frequency and remains -92dB at the frequency higher 1MHz. The proposed circuit operates stably at the supply voltage higher 1.2V and has good process compatibility.