An all switched-capacitor structure realized piezoresistive pressure sensor interface chip for automotive tire pressure monitoring system is presented. The propose integrated circuit consists of high resolution incremental ADC, low noise switched-capacitor amplifier, high accuracy bangdap reference and low-power relaxation oscillator and other related blocks. Proposed structure was implemented in standard 0.35µm CMOS process with an area of 6.1mm2. The experimental results show that the signal conditioning method provides high accuracy of 1% of the full scale output with a battery voltage from 3.6V to 2.1V over the full military temperature range. The charge consumption results into 25mAh in 10 years, including sleep mode and junction leakage current.
A pipelined analog-to-digital converter (ADC) has been investigated, which has a programmable gain achieved by the gain control in a first-stage multiplying digital-to-analog converter (MDAC). The current consumption reduction under low gain is realized by controlling the transconductance and compensation capacitor of the MDAC circuit according to the input gain. The pipelined ADC designed using a 0.18µm CMOS technology shows a sampling rate of 40MSps and an input gain of 0-18dB (6dB-step). The maximum current consumption is 14.2mA at the input gain of 18dB and the minimum is 7.5mA at 0dB. The signal-to-noise plus distortion ratio (SNDR) is 66.1dB for an input signal amplitude of 2Vpp and an input gain of 0dB, and 63.4dB for an input signal amplitude of 250mVpp and an input gain of 18dB.
To innovate new devices such as nanowire (NW) metal-oxide-semiconductor field-effect transistors (MOSFETs), fully analytic and explicit models become vastly more important as TCAD tools for device design and circuit simulation, but such tools have yet to be reported. In the present article, we propose a fully analytic and explicit model of ballistic and quasi-ballistic NW MOSFETs. Device properties are derived analytically in terms of one common parameter. This common parameter is obtained analytically by means of a one-of-a-kind approximation technique, which also achieves the desired fully analytic and explicit model. Finally, we demonstrate circuit simulations using the model.