# (ADuM5401)I have few question about ADuM5401.

Hi !

I have few questions about ADuM5401.

1)=================================================================

For DC-DC output voltage , the datasheet p3 says the condition is VDD1=5V.

And Setpoint : Viso Min = 4.7V , typ = 5V,Max = 5.4V.

Does this means

(A) if we input 5V , the output will change 4.7V~5.4V?

Or

(B) does this means if we input 4.5~5.5V , the output will change 4.7V~5.4V?

If (B) is correct, is it possible that if we input 4.5V, the output will be 4.7~5.4V?

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2)=================================================================

For the Line regulation,  the value is 1mV/Vtyp .

How should we calculate about this.

Does this value means 1mV/V is 5V condition ?

For example

Vdd1=5.5V  ; 1mV*(5.5-5)=0.5mV

Vdd1=4.5V  ; 1mV*(4.5-5)=-0.5mV

Can you explain how to use this value?

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3)=================================================================

At P7 of datasheet, the condition is "VDD1 = 4.5min~5.0typ~5.5Vmax.

But at Table10, Line regulation comments , it says VDD1=3.0~3.6V.

Is this typo?

Which is correct?

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4)=================================================================

The datasheet says Load Regulation will change 5%.

So to take care about this is like...

・Viso=5Vtyp     ; 5×5%=0.25V      → Viso=5-0.25=4.75Vmin

・Viso=4.7Vtyp   ; 4.7×5%=0.235V   → Viso=4.7-0.235=4.465Vmin

Is my understanding are correct?

With question No.1 , the setpoint is just the target value so we have to take care about Load regulation too.

Is my understanding are correct?

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5)=================================================================

At Figure21 & Figure22 it looks like At 1Mbps , Iiso = 0mA.

Does this means when the Frequency is lower than 1Mbps,　I can ignore it?

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Best regards.

Kawa

• Kawa-san: My response to your questions:
1.Page 3 says the condition is VDD1=5V.And Setpoint : Viso Min = 4.7V , typ = 5V,Max = 5.4V.

Yes, if we input any voltage VDD1 = 4.5V to 5.5V, Viso output range = 4.7V to 5.4V for Iiso = 0mA.

2. Yes, this is how you use the line regulation spec. If the line regulation for the users power supply has a tighter spec than 4.5V to 5.5V, the effect would be reduced.

3. Yes, this is a typo, the conditions should say VDD1 = 4.5V to 5.5V.

4. Yes, the load regulation spec can be used like this to predict output voltage setpoint variation for load variation.

5. Yes, when data frequency is less than 1Mbps you can ignore the Iiso load.

Regards, Brian

• Hi Brian!

Thank you for your answer.

I understood.

Best regards.

Kawa