AMC1311: Using an isolation amplifier with Vdd1 > Vdd2.

Lewis Jones

Part Number: AMC1311

Is it possible to configure an isolation amplifier, e.g. ADuM3195, such that Vdd1, on the output side, is higher than Vdd2 on the input side?

It does not seem to work in Spice, but that might not mean that it cannot work in the physical universe.

Thanks,

Lewis

11 months ago

0 Eva Mason 11 months ago

TI__Expert 5975 points

Hi Lewis,

You can definitely have VDD1 powered at 5V and VDD2 powered 3.3V if that is what you mean. As long as you are within the recommended operating conditions for your power supplies, this should be fine.

Best regards,

Eva

0 Lewis Jones 10 months ago

Prodigy 10 points

Thanks Eva, What I mean is, can the amplifier be operated with GND1 say, 30V, above GND2? I am talking about having the Vdd1 and Vdd2 5V above their respective GND pins.

Thanks,
Lewis.

0 Clemens Ladisch 10 months ago in reply to Lewis Jones

Guru 284810 points

Yes; such difference are the whole reason for having isolation.

(Many Spice models contain errors where some internal ground is connected to the circuit's 0 V instead of the GND pin.)

0 Eva Mason 10 months ago in reply to Lewis Jones

TI__Expert 5975 points

Hi Lewis,

Yes, that is fine since they are within 5V of their GNDs, and this is an isolation device.

Best regards,

Eva

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AMC1311: Using an isolation amplifier with Vdd1 > Vdd2.