A 0.8V 1.52MHz MSVC Relaxation Oscillator with Inverted Mirror Feedback Reference for UHF RFID

Abstract

A 0.8V nano-power relaxation oscillator for EPC standard UHF RFID transponder is presented. A low-voltage inverted mirror feedback VGS/R reference is proposed to provide correlated current and voltage references for the oscillator. As a result, the oscillator frequency is solely determined by the resistor in the reference and the timing capacitor to meet the frequency tolerance specification. Meanwhile, to minimize the power consumption, a minimum-supply-voltage-constraint (MSVC) design criterion is proposed to minimize the required supply voltage. The inverted mirror feedback technique reduces the headroom requirement of the traditional VGS /R to meet the MSVC. Measurement results show that the entire oscillator requires a minimum supply voltage of 0.8V in the prototype chip fabricated in CMOS 0.13mum technologies. The measured oscillation frequency is 1.52MHz with 400nA total current consumption. The chip area is 13400mum2