关键词: 熔丝修调, 开关电容, 基准电压源

Abstract: A high precision switch capacitor reference voltage source with adjustable output is designed. Compared with existing reference voltage sources, this circuit can correct the reference voltage at the wafer stage using fuse trimming technology to reduce the chip manufacturing cost. The circuit adopts switch capacitor structure to reduce the impact of the offset voltage on the operational amplifier and has high accuracy. The reference voltage source is applied to a speech codec chip, and the test results show that the reference voltage is 2.355 V at 25 ℃, and the temperature coefficient is 19.46×10^-6/℃ in the range of -40-80 ℃.

Key words: fuse trimming, switch capacitor, reference voltage