Use of ADuM6211 and ADM3101E

Hi Teruamsa,

For the application setup described, i think that the  current from Viso of ADuM6211 meets the requirements of VDD2 of ADuM6211 and VCC of ADM3101E.

VDD2 of ADuM6211:
power supply current : 2.3 mA  Max.

VCC of ADM3101E:
power supply current : ~12mA at 1000 pF load.

2.3mA + 12mA = 14.3mA total.

Current from Viso of ADuM6211 is 20mA max at VDDp 77mA.
So the current from Viso of ADuM6211 meets the requirements of VDD2 of ADuM6211 and VCC of ADM3101E.

Regards,

Richard

Hello RAnslow,

Thank you for your reply.

I do not know  one point about your advice.

Please let me know your advice.

Datasheet P.3 says that power supply current is 7mA MAX at 3Kohm load resistance.

Datasheet P.6 FIgure 9 says poewr supply current for load capacitance.

I tought that there is a current for load resistance of input resistance of receiver and a current for load capacitance of a cable.

So,  in the condition of using cable and receiver,

I tought that needed current is total of 2.3mA (ADuM6211) and 7mA (ADM3101E) and 12mA (1000pF) =21.3mA .

Is above my understanding wrong ?

If so, please let me know your advice how to use for  Figure 9 (load capacitance) and P.3 power supply current ( load resistance)   in estimating total current .

Please let me know your advice.

Best Regards,

Terumasa

Hi Terumasa,

Yes, you are correct.

The current required is: ADuM6211 (VDD2) + ADM3101E (load of receiver input resistance) + ADM3101E (bus cable capacitance).

The receiver input resistance is specified to be between 3 kΩ and 7kΩ, 5 kΩ is used as a typical, and 3 kΩ is the worst case from a power point of view.

So, the 7mA in the data sheet is a worst case scenario.

Under typical operation for 3 kΩ the current could be 5 mA or less, allowing you to come in less than 20mA for the overall application.

If you can increase the power supply voltage of the ADuM6211 to one of these setups;
5 V PRIMARY INPUT SUPPLY/5 V SECONDARY ISOLATED SUPPLY
5 V PRIMARY INPUT SUPPLY/3.3 V SECONDARY ISOLATED SUPPLY
Then you can provide up to 30mA from Viso of ADuM6211.

This might be an alternative for this customer ?

Regards,

Richard

Hello RAnslow,

Thank you for your answer.

I checked your adviec for my customer but

It is difficult for customer to add 5V supply for isolated DC-DC  only,

so I am introducing ADuM6201 which can supply 40mA at 3.3V supply.

Best Regards,

Terumasa