什么是运放的偏置电压？

只看该作者 · 2007-5-15 08:55

什么是运放的偏置电压？有什么影响？
如果偏置电压值是x，放大电路为放大5倍，
那么输出端是否会有一个偏压 5*x呢？

3万 · 2007-5-15 10:46

楼主说的，好像是失调电压。

2万 · 2007-5-15 11:02

有些工程师不知为何习惯说成偏置电压

1万 · 2007-5-15 11:52

设rail-to-rail输入电压可以低到0 V,如不然，则要有一定的偏置电压。如LM324

1万 · 2007-5-15 12:07

单电源IC，必须注意这个问题。

Maxim有beyond-the-rail，允许输入略负于地电平。
ADI同样的情形如：ADuC824的32～33页---

Analog Input Ranges

The absolute input voltage range on the primary ADC is restricted
to between AGND + 100 mV to AVDD – 100 mV. Care must be
taken in setting up the common-mode voltage and input voltage
range so that these limits are not exceeded, otherwise there will
be a degradation in linearity performance.

The absolute input voltage range on the auxiliary ADC is restricted
to between AGND – 30 mV to AVDD + 30 mV. The slightly
negative absolute input voltage limit does allow the possibility of
monitoring small signal bipolar signals using the single-ended
auxiliary ADC front end.　这种情形不多，但有时非常有效----不需要偏置电压（共模电压）抬高信号电平。

http://www.analog.com/UploadedFiles/Data_Sheets/ADUC824.pdf