完全差分和准差分——AD7705和AD7706的区别
The AD7705 contains two programmable-gain, fully differential analog input channels, and the AD7706 contains three pseudo differential analog input channels. The selectable gains on these inputs are 1, 2, 4, 8, 16, 32, 64, and 128, allowing the parts to accept unipolar signals of 0 mV to 20 mV and 0 V to 2.5 V, or bipolar signals in the range of ±20 mV to ±2.5 V when the reference input voltage equals 2.5 V. With a reference voltage of 1.225 V, the input ranges are from 0 mV to 10 mV and 0 V to 1.225 V in unipolar mode, and from ±10 mV to ±1.225 V in bipolar mode. Note that the bipolar ranges are with respect to AIN(-) on the AD7705, and with respect to COMMON on the AD7706, but not with respect to GND.
http://www.analog.com/static/imp ... ets/AD7705_7706.pdf
两者具体的电路形式到底如何,另详。 |