Thermal shutdown of LP5907

Hi Takahiro,

The thermal shutdown threshold is set at 160C for a variety of reasons. A few examples include:
1) Package handling temperature. Some plastic packages suffer degraded reliability quickly once the case temperature gets into the 170C+ region. 160C provides margin from that area
2) Solder. Leaded solder melting point is ~180-190C, so again the 160C provides margin from keeping the temperature away from that away
3) Device operation. A lot of variables in silicon-based device models start to turn non-linear in as the temperature gets significantly above 160C. An example is leakage currents - they get exponentially larger at high temperatures. These variables can cause abnormal device operation.

In summary, a lot of factors play into why thermal shutdown is typically kept near 160C.

Regards,
David