• Journal of IKEEE
• /
• v.24 no.4
• /
• pp.975-981
• /
• 2020

A 10 GHz LC voltage-controlled oscillator (VCO), which controls an amplitude of output signal, is proposed to improve the phase noise. The proposed amplitude control circuit for the LC VCO consists of a peak detector, an amplifier, and a current source. The peak detector is performed detecting the lowest voltage of the output signal by using two diode-connected NMOSFET and a capacitor. The proposed 10 GHz LC VCO with an amplitude control circuit for output signal is designed using a 55 nm CMOS process with a supply voltage of 1.2 V. Its area is 0.0785 ㎟. The amplitude control circuit used in the proposed LC VCO reduces the amplitude variation 242 mV generated in the output signal of the conventional LC VCO to 47 mV. Furthermore, it improves the peak-to-peak time jitter from 8.71 ps to 931 fs.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.6 s.360
• /
• pp.8-18
• /
• 2007

In this paper, a 4bit cell way structure of PoRAM and the sensing method to drive this structure are researched. PoRAM has a different operation from existing SRAM and DRAM. The operation is that when certain voltage is applied between top electrode and bottom electrode of PoRAM device we can classify the cell state by measuring cell current which is made by changing resistance of the cell. In the decoder selected by new-addressing method in the cell array, the row decoder is selected "High" and the column decoder is selected "Low" then certain current will flow to the bit-line. Because this current is detect, in order to make large enough current, the voltage sense amplifier is used. In this case, usually, 1-stage differential amplifier using current mirror is used. Furthermore, the detected value at the cell is current, so a diode connected NMOSFET, that is, a device resistor is used at the input port of the differential amplifier to converter current into voltage. Using this differential amplifier, we can classify the cell states, erase mode is "Low" and write mode is "High", by comparing the input value, Vin, that is a product of current value multiplied by resistor value with a reference voltage, Vref.