TPL5010-Q1: Clock Watch Dog

Hi Kevin,

The minimum programmable timer resolution for the TPL5010-Q1 is 100ms. If checking no more than once every 100ms is acceptable, the TPL5010-Q1 will work. But if finer resolution is required, a different solution is needed.

Regards,

Hi Kevin,

TPL5010-Q1 is the only automotive-grade nanotimer we have, so try with this first.

• Connect the DONE pin to the 25 MHz signal
• Program the monitoring time with a resistor from DELAY/M_RST to GND (see table 3 and table 4 in the datasheet)
• Leave the WAKE pin floating
• Connect RSTn as the loss of signal indicator

If the 25 MHz clock is gone, the DONE signal will never be asserted after a WAKE timer starts. So the timer will eventually send a pulse on RSTn.

The datasheet says the minimum DONE pulse width should be 100 ns, which is technically 5x longer than the positive half of the 25 MHz clock signal. But I don't think this will be an issue, because every WAKE timer interval has at least 2.5 million chances to see the DONE pulse. Also, TPL5000 and TPL5010-Q1 have very similar circuits, and the TPL5000 datasheet claims to require a minimum pulse width of 100 ns for the DONE pulse, but when DONE is connected to TCAL the pulse width is actually 20 ns and it works fine. 

Regards,