LTC4421: Extending the Input Voltage Range

Hello

In my project I have two voltage rails with with nominal voltage +48V. (+40V...+60V range)

LTC4421 have a very good functionality, but limited with +45V input voltage.
( I can not understand "60V tolerance" declared at first page of datasheet, because Out max. voltage is 45V) 

Is there any application note, ref. design for using LTC4421 at higher voltage available?
There are Application Note 107 "Extending the Input Voltage Range of PowerPath
Circuits for Automotive and Industrial Applications" with circuits using Zener and resistor.

But AN107 describe simple circuits.

I would like to know if such approach work with LTC4421. I think the main issue is connecting UVF, UVR,OV inputs.

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  • +1
    •  Analog Employees 
    on May 25, 2021 1:58 PM

    Hi,

    The LTC4421 is specified, on the datasheet, to function over the range 3 - 36V.

    The Absolute Maximum Ratings define the voltage levels at which the part will be damaged. The functionality between the maximum operating voltage and the Absolute Maximum Ratings is not guaranteed.

    The Application note, AN107, is written about the LTC4412 and LTC4414, much simpler devices than the LTC4421.

    There will be lots of issues, with the analog signals (UVF, UVR, OV etc) and the digital signals (VALID#,  CHx, etc) if the ground is floating.

    I do not recommend trying to extend the voltage range of the LTC4421.

    Regards,

    JayBee

Reply
  • +1
    •  Analog Employees 
    on May 25, 2021 1:58 PM

    Hi,

    The LTC4421 is specified, on the datasheet, to function over the range 3 - 36V.

    The Absolute Maximum Ratings define the voltage levels at which the part will be damaged. The functionality between the maximum operating voltage and the Absolute Maximum Ratings is not guaranteed.

    The Application note, AN107, is written about the LTC4412 and LTC4414, much simpler devices than the LTC4421.

    There will be lots of issues, with the analog signals (UVF, UVR, OV etc) and the digital signals (VALID#,  CHx, etc) if the ground is floating.

    I do not recommend trying to extend the voltage range of the LTC4421.

    Regards,

    JayBee

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