Hello,
The LM5022 datasheet specifies the abs max voltage level at the UVLO input as 7V.
There is no max value specified.
In the customer's application the input working voltage is 10.5V to 60V.
To ensure this functionality, a 105K + 14k7 UVLO voltage divider was chosen.
At 60Vin the UVLO voltage calculates to 7.37V nominal, potentially higher with 1% tolerance resistors.
I would expect that at that voltage level the hysteresis current generator is no longer functional (saturated).
However, the DC probing of the UVLO pin reads 6.25V which i cannot explain.
1. what is the UVLO maximum allowable voltage?
2. what is the UVLO input current leakage?
3. does the UVLO input have clamping diodes to the comparator's internal bias?
4. if clamping is present, what is allowable current into the diode?
5.if no clamping occurs, is external clamping circuitry needed and what woud be recommended as a low cost solution - a DZ has significant leakage over temp itself, a 431 clamp adds cost and parts count.
there is no app note in the datasheet for this in-spec use case
Thank you.
