A Low-noise 2.5V 4-ppm/℃ 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 digital-to-analog converter (DAC) in 180nm complementary metal oxide semiconductor (CMOS) process. A proportional-to-absolute-temperature current (PTAT) and an adjustable complementary-to-absolute-temperature current (CTAT) are introduced to obtain a low temperature coefficient (TC) reference voltage. A large scale metal-oxide-semiconductor field-effect transistor (MOSFET), which works in subthreshold region, is introduced to compensate V_T lnT term. To overcome the variation of process voltage temperature (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 24 dB decrease at lower frequency and up to 5 dB 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 metal-oxide-semiconductors (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 2.5 V. The maximum output noise power spectral density (PSD) is less than 8.5 μV/Hz². The maximum spurious free dynamic range (SFDR) of multi-channel DAC with proposed low-noise voltage reference is −80 dBc @ 1.245 KHz output at −40 ℃, 25 ℃ and 105 ℃.