ltm4650-1 there's an error in Vout

Hello, 

Can you double check below?

1) Multimeter reading for VOUT is 1.68V?

2) R257 =103.5K?

3) VFB=0.6V?

4) VOSNS1 is not connected to VOSNS2?

Thank you. 

Hi Haihua,

VFB=0.55V,others' ok. is there any problems in vfb ?

Hello Abby,

The Differential remote sensing DIFFP and DIFFN are measuring the output voltage with net list called

VCC_0.9V_3 while the local output voltage for this module has the net list name VCC_0.95V_1. 

Are these two net list connected together?

If DIFFP and DIFFN are used to be connected to remote sensing location, is there any load connected already?

If there is no load and DIFFP and DIFFN are floated, then there is no output voltage can be observed.

At this condition, can you try to connect a resistor such as 10ohm between DIFFP and VOUT, DIFFN and GND respectively?

Thanks

It's always loaded.

Hello Abby,

I saw you have correct the schematic and please ensure in the layout DIFFP and VOUT pin do get connected.

Let us know if you still have issue after try the suggestions mentioned before. 

Thanks 

Hi Haihua,

Additoon a resistor  10ohm between DIFFP and VOUT, DIFFN and GND are hard to change after all the layout is finished.

and then, as you see, the below shcematic is anther one output is 0.95V which is normal working.

So it's not falut in connection between DIFFP and VOUT, DIFFN and GND.

Anything else part need to be make sure on this case?

Hello Abby,

The schematic looks good with me if the proposed VOUT and VOUT_SENSE pin are tied together as recommended.

Please check the assemble then.

Thank you. 

Hi HAIHUA，

May I have a doubt between vref and voust1 ?  

Hello Abby,

There is no problem on your schematic connection. Please see datasheet page 12 regarding this part of the connection.

Thanks