What is the output of the Wake pin by default on the TPL5010?

Hello, I've notified an engineer to respond.

Hi Jake,

To answer your first question:  The output pulse on the WAKE pin is only seen if a DONE signal is received from the MCU within the required time period. The WAKE signal is normally low unless otherwise triggered by the receiving of a DONE. The TPL only recognizes a valid DONE signal as a valid low to high transition. So in other words, to "enable" the WAKE output, it must be followed before by a valid DONE.

To answer your second question: The TPL will not output a WAKE if no DONE input is received. Instead, a periodic RSTn signal will take place. The period of the RSTn (as seen on Pg. 8 of the datasheet) is the sum of RSTn Pulse width and your 500ms. However, in your case the weight of the RSTn width will affect your timing for a 2Hz clock. You can try reducing the value of  the time interval (to around 200ms) and effectively attain roughly a 500ms period pulse, granted precision is not a concern. 

Hope this helps.

-Nikhil Dua

Hello Nikhil,

Thank you for the response. What If I am able to supply a signal to the DONE pin that is a low to high transition to the chip but then signal stays high? Will the WAKE still output a pulse 500 ms after the DONE signal?

If this works I can then use a chain of these chips by connecting the WAKE pin to the DONE pin of the next and it will set off one at a time at each 500 ms interval, is that correct? If so I could even create a chain of 3 and then have the last IC WAKE pin loop back to the second IC DONE pin with an OR gate (other input would be WAKE pin of first IC) and that way the last two ICs will be always running and producing a pulse every 500 ms.

I also like your idea of using the RSTn pin and modifying the pulse so that it is 500 ms total. How much max over the temp range can you estimate Trstn is?

Thank you,

-Jake

Hi Jake,

If a DONE signal is supplied to the TPL (at least 20ms before the rising edge of the next WAKE pulse) and that signal stays high, then only one WAKE signal will be issued which will kickstart the beginning of the next time interval. To get another WAKE pulse afterwards, you must issue another DONE (low to high transition), again at least 20ms before WAKE's rising edge. The timing of the WAKE is purely dependent on the interval selected. Receiving a DONE in the valid timefame only tells the TPL that a WAKE is to be issued at the beginning of the next time interval.

As for the temp. range, I will have to check and get back to you on that.

Regards,

Nikhil

Hello Nikhil,

I am a little confused again. Upon startup/poweron of the IC what is the output of the WAKE pin if the DONE Pin is held low? Does it ever output a pulse or is it low always?

The next question is the timing. When does the timer start for the WAKE pin? lets say I want it to be set at 500 ms delay. Does the WAKE pin put a pulse out exactly 500ms after it gets a DONE signal? Then will it output another exactly 500 ms after or wait for another DONE signal?

Hello Nikhil,

I understand now. Thank you. This could cause problems in my design if I am using one WAKE to feed into another DONE signal. I will have to make sure the timing is right for the DONE to receive the correct wake pulse before 20ms cutoff. I have one last question regarding the datasheet:

In the datasheet Section 7.5 (page 5) under IDD it says "Digital conversion of external resistance (Rext)" What does this mean? I wanted to use this chip because I thought the supply current was in the nano-amps? I definitely can't use it if its in the hundreds of microamps range. Please let me know what this specification means. Thank you,

-Jake

Thank you,

This may still work but the POR might be too long for our application. Thank you for helping with everything I need from this chip.

-Jake