This design note introduces the LTC®4365, a unique solution that elegantly and robustly protects sensitive circuits from unpredictably high or negative supply voltages. The LTC4365 blocks positive voltages as high as 60V and negative voltages as low as –40V. Only voltages within the 5V to 36V window can pass through the device. The LTC4365 uses a high voltage window comparator and charge pump to achieve low power, reliable overvoltage and undervoltage protection.
The document introduces the LTC4365 as a unique solution to protect sensitive circuits from unpredictably high or negative supply voltages. It explains how the device blocks positive voltages up to 60V and negative voltages down to -40V, passing only safe operating supply ranges to the load.
| Maximum positive blocked voltage | 60V |
|---|---|
| Minimum negative blocked voltage | -40V |
| Operating range minimum | 2.5V |
| Operating range maximum | 34V |
| Shutdown current | 10pA |
The only external active component required is a dual N-channel MOSFET connected between the unpredictable supply and the sensitive load.
Yes, after an OV or UV fault occurs, the input supply must return to the valid window for at least 36ms, which effectively blocks 50Hz and 60Hz unrectified AC.