Can the voltage VS- pin (VS3- for ADP1046A) of ADP1050/51/55 operate at a voltage higher than 0.3V?

Document created by james.xie on May 18, 2014
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In the data sheet of ADP1046A and ADP1050/51/55, the VS- pin (VS3- pin for ADP1046A) voltage should be within -0.3V ~ +0.3V referred to AGND pin. However,  since the VS- is the negative remote voltage sense input, the load voltage sense point (remote voltage) might be far away from the local ground AGND. Therefore the VS- voltage may be higher than +0.3V. Can it work?

 

According to the diagram shown in the attachment, the VS+ and VS- pins are differential inputs of a differential amplifier. The voltage of both input pins can operate at a voltage higer than 0.3V. So it is safe that the VS- operates at a voltage higher than 0.3V.

 

However, the user need to consider twol points:

1. All the digital power products are charactered at a VS- voltage of +-200mV. The specifications in the datasheet are not graranteed if the VS- voltage higher than 0.3V.

2. The long copper and high voltage drop between the PSU output and load might introduce common mode noise. A filter circuitry is recommended (See the layout guidelines setion in the data sheet)

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