请教个关于DAC buffer的问题

AcoAco

这个问题是很常见的所有商业的轨到轨输出的单电源运算放大器，它成为最差的更高的负载电流。只有这样，才能覆盖GND水平，充分BW的循环使用负电源轨到包括GND循环将被打破。由于电流吸收器可用于（A类输出），这个电流吸收器将提供一个良好的PSRR比型负电荷泵电源（纹波），可用于提供输出电流驱动能力是足够小，以保持芯片面积合理的小。祝你好运。

This problem is common with all the commercial rail to rail output single power supply OPAMPs and it becomes worst with higher load currents.  Only way to cover GND level with full BW of the loop is to use negative power rail to cover GND where loop will not be broken.  Since a current sink could be used (Class A output) and this current sink would provide a good PSRR- than a Charge Pump type negative power suply (has ripple) could be used provided that your output current drive capability is small enough to keep chip area reasonable small. Good luck.

afujian

回复 11# AcoAco
Thanks for your explanation!

superpeng2012

学习了