AMC1300EVM: Does anyone have an experience with this board ?

Hello Riko,

Please be safe and take necessary precautions when working with high voltages. You will need to condition the input source down to the input range of the AMC1300 (+/-250mV) using a resistor divider. If you haven't worked on similar designs beware that you'll likely need a few resistors in series for the leg of the divider that drops the majority of the voltage to keep the drop across the invididual resistors to a more reasonable level.

Guidance on selecting the appropriate resistance valuess while using the AMC1300 in a voltage sensing application can be found in the AMC1301 datasheet on page 23 in Section 10.2.2. You'll need to use the AMC1300 input impedance specifications in place of the AMC1301 shown in the example.

Another option would be to consider the ISO224 which can accept up to a +/-12V input signal on a single-supply connection and has a high impedance input stage and will work better with higher resistor divider values.

Hello,

Yes, the same guidance applies to the AMC1302 with the exception that the input range is +/-50mV vs. +/-250mV. Both of these devices are optimized for current measurements but can be used for voltage measurements with the gain errors that are calculated in the AMC1301 datasheet.

Here is a good article from one of my colleagues on high-voltage sensing designs which includes the effects of power dissipation and voltage coefficient of resistance due to the high voltage drop across the resistors. You will also need to verify the individual resistors can tolerate the voltage drop they'll have across them and likely use several in resistors in series to minimize the drop across any one resistor.

www.eeweb.com/.../considerations-for-high-voltage-measurements

If you don't use R3 you should use the calculation in Equation 1 to determine the gain error. If you do use R3 you'll use equation 2. If R3 is much smaller than Rin you likely won't need R3'.