A Low-noise 2.5V 4-ppm/°C Voltage Reference Used for a 16-bit High-Precision DAC in 180nm CMOS Process

This paper proposes a low-noise 2.5V 4-ppm voltage reference used for a 16-bit high-precision DAC in 180nm CMOS process. A proportional-to-absolute-temperature current and an adjustable complementary-to-absolute-temperature current are introduced to obtain a low temperature coefficient (TC) reference voltage. A large scale MOSFET , which works in subthreshold region , is introduced to compensate VTlnT term. To overcome the variation of PVT, two sets calibration resistor arrays are integrated to calibrate the TC and output voltage of voltage reference. A gain boost amplifier is introduced to voltage reference to obtain a better power supply rejection (PSR), and up to 24dB decrease at lower frequency and up to 5dB decrease at higher frequency are achieved. The proposed high precision and low noise output buffer is used to provide current for multi-channel high-precision DAC and 4 MOSs are replaced to BJTs to reduce noise of output reference voltage. A 4-ppm/℃ of temperature coefficient (TC) is obtained from -40℃ to 105℃, while the output voltage is 2.5V. The maximum output noise power spectral density (PSD) is less than 8.5 μV/sqrt (Hz). The maximum spurious free dynamic range (SFDR) of multi-channel DAC with proposed low-noise voltage reference is -80dBc@1.245KHz output at -40℃, 25℃ and 105℃.