LTC4281 maximum voltage

Question

I would like to use the LTC4281 in an application where the monitored power rail reaches 34 VDC. This is below the absolute maximum rating for the device (45V) but is above the "input supply range" rating (33V max). It would appear that the only downside of operating above 33V is that the rail voltage measurement would be above the full-scale range of the ADC (33.28 V). Some questions: 
 1) is the current measurement aspect of the device still operational at this higher common mode voltage? 
 2) Are there any other downsides to operating at 34 VDC?

JayBee · Answer

It will be difficult to find a TVS diode that will not conduct when operating at the maximum input and clamp the voltage generated when the LTC4281 breaks the fault current under severe short circuit conditions. 
 
 I suggest that you look at using a higher voltage hot swap controller like the LTC4286 or the ADM1272. 
 
 Regards, 
 JayBee

JayBee · Answer

Are you hot-plugging the LTC4281 circuit or is it being used an eFuse and permanently connected to the power supply? 
 
 JayBee

JayBee · Answer

The LTC4281 will not be damaged unless the ABSmax voltages (or currents) as described on the datasheet are exceeded. 
 The LTC4281 is only guaranteed to meet it published specification over the range 2.9 to 33V. As you have pointed out the ADC for measuring input and output voltage has a full scale of 33.2V. The ADC for Vin and Vout and by extension the power telemetry will be impacted. 
 I am unable to comment on if the current sensing and measurement circuit is fully functional above 33V, this would be operating outside of the published specifications. 
 
 JayBee

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LTC4281 maximum voltage