Sub-1 V,pico-watt subthreshold CMOS voltage reference circuit with dual temperature compensation

A pico-watt CMOS voltage reference is developed using an SK Hynix 0.18 µm CMOS process. The proposed architecture is resistorless and consists of MOSFET circuits operated in the subthreshold region. A dual temperature compensation technique is utilized to produce a near-zero temperature coefficient reference output voltage. Experimental results demonstrate an average reference voltage of 250.7 mV, with a temperature coefficient as low as 3.2 ppm/°C for 0 to 125 °C range, while the power consumption is 545 pW under a 420 mV power supply at 27 °C. The power supply rejection ratio and output noise without any filtering capacitor at 100 Hz are −54.5 dB and 2.88 µV/Hz^1/2, respectively. The active area of the fabricated chip is 0.00332 mm².     

A novel current reference based on subthreshold MOSFETs with high PSRR

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 0.18 μm standard CMOS logic process technology, exhibits a stable current of about 1.701 μA with much low temperature coefficient of 2.5×10⁻⁴ μA/°C in the temperature range of −40 to 150 °C at 1.5 V supply voltage, and also achieves a best PSRR over a broad frequency. The PSRR is about −126 dB at dc frequency and remains −92 dB at the frequency higher 1 MHz. The proposed circuit operates stably at the supply voltage higher 1.2 V and has good process compatibility.     

Design of Sub-1 mW CMOS LC VCO based on current reused topology with Q-enhancement and body-biased technique

A CMOS LC voltage controlled oscillator (VCO) based on current reused topology with low phase noise and low power consumption is presented for IEEE 802.11a (Seller et al. A 10 GHz distributed voltage controlled oscillator for WLAN application in a VLSI 65 nm CMOS process, in: IEEE Radio Frequency Integrated Circuits (RFIC) Symposium, 3–5 June, 2007, pp. 115–118.) application. The chip1 is designed with the tail current-shaping technique to obtain the phase noise −116.1 dBc/Hz and power consumption 3.71 mW at the operating frequency 5.2 GHz under supply voltage 1.4 V. The second chip of proposed VCO can achieve power consumption Sub 1 mW and is still able to maintain good phase noise. The current reused and body-biased architecture can reduce power consumption, and better phase noise performance is obtained through raising the Q value. The measurement result of the VCO oscillation frequency range is from 5.082 GHz to 5.958 GHz with tuning range of 15.8%. The measured phase noise is −115.88 dBc/Hz at 1 MHz offset at the operation frequency of 5.815 GHz. and the dc core current consumption is 0.71 mA at a supply voltage of 1.4 V. Its figure of merit (FOM) is −191 dBc/Hz. Two circuits were taped out by TSMC 0.18 μm 1P6M process.