ADE7903

Hi Nuno

Please find my responses below:

1. The Evaluation board does not have any shunts on it. While performing system level tests using the evaluation board, external shunts must be used. However, you can find a couple of important specs below, that you should look for, in a shunt’s datasheet:

    i) The resistance value of the shunt will mainly depend on the maximum application load current. The signal going into the ADE7903 IC must be within the full-scale range of the ADCs (+31.25mVpeak). For safety, I would back up by some margin from the full-scale level, i.e., setting the application maximum current level to say, ½ full scale.

    ii) The temperature co-efficient of the shunt is another important aspect. You should pick one, whose resistance value doesn’t vary too much with temperature. The gain drift specs for the current and voltage channels are provided in the ADE7903 datasheet. Using these values, you can see if the shunt’s drift will satisfy the system level requirements for accuracy.

2. Yes. Voltage divider needs to be used to step down the voltage level. The three series resistors (that you refer to) form a divider network along with the 1kohm resistor (Refer to page 11 of Rev.0 datasheet). Any doubts on this still?

3. The diodes are used in the evaluation board for over-voltage protection- to make sure that the IC isn't damaged due to some large signals (> +2V: Absolute max ratings) entering the IC pins. If this sort of protection is taken care of at the meter level in a different way, then this is not needed.

Regards

hmani