A trimmable precision bandgap voltage reference on 180 nm CMOS

Abstract

For the operation of a successive approximation register analog-to-digital converter, an integrated reference voltage source is required. This reference has to be stable and has to have high precision. Therefore, trim mechanisms for the achievement of optimal accuracy and minimum temperature drift behavior are necessary.Generally, Kuijk and Brokaw bandgap reference topologies are suitable for these requirements. The Kuijk bandgap reference has typically a very good power supply rejection ratio (PSRR). But adequate noise performance and temperature drift behavior cause relatively high current and area consumption. In contrast to the Kuijk topology, the Brokaw reference circuit has better noise performance and temperature drift at a lower quiescent current. Depending on the topology, the Brokaw reference normally has lower PSRR.For implementation, the Brokaw reference has been chosen. It has a nominal output voltage of 1.25 V with an absolute accuracy of 600 µV after trimming. The temperature drift in the range of -55 • C to 125 • C is typical 22.8 ppm/ • C. The DC power supply rejection ratio (PSRR) is more than 84 dB over all relevant corners. The minimum power supply rejection ratio is 59 dB at approximately 1 MHz. The overall current consumption at ambient temperature is maximal 59 µA.

A New Successive Time Balancing Time-to-Digital Conversion Method

“…Following the above, the smallest capacitor C 0 was set to 500 fF. The reference voltage V REF , to which the capacitors C 7 , …, C 0 are linearly charged, has been set to 1.2 V, which is around the typical value for the real bandgap voltage reference circuits [ 37 , 38 , 39 , 40 , 41 , 42 ].…”

“…. ., C 0 are linearly charged, has been set to 1.2 V, which is around the typical value for the real bandgap voltage reference circuits [37][38][39][40][41][42].…”