lt1990 macro model measuring 200VDC with +/-15V

Question

Is this correct Vout is following V-? 
 VDC=200V 
 V+=15V 
 V-=-15V 
 Vout=-15V 
 
 below is EVB with added 49.9kohm resistor at the output.

How shall i configure LT1990 to feed into 4.096V ADC?

ADIApproved · Accepted Answer

Hi jiamin: In the first case, the LT1990 output is clipped against the bottom supply as it tries to reproduce -200V. In the 2nd case, the load is too heavy so the output is crushed towards ground. The LT1990 is made for medium small voltages on top of large common modes. 
 You're trying to compress 200V into 4V, which is a divide by 50. The closest we have is probably the LT1997-2, which will do a divide by 14.5. That would at least get the output within the +/-15V supplies, and then you could further attenuate after that.)

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lt1990 macro model measuring 200VDC with +/-15V

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