MCT8316Z: DC/DC converter doesn't start up

Hi Ralf,

Please verify nSLEEP pin status?

Please provide schematic to review.

Thanks and Best regards

Venkatadri S

I used the example application exactly as in the dazasheet (pg. 78):

This means, of course, that nSLEEP is initially low.

Hi Ralf,

Did you verify nSLEEP is low?

Thanks and Best regards

Venkatadri S

Hi Venkatadri,

of course nSLEEP is low. it can't be high as you can see from the datasheet's application schematics:

The Microcontroller is sourced from AVDD. If AVDD is initially switched off, the Microcontroller *cannot* deliver a high signal on nSLEEP.

I tried with a high resitance (~300kOhms) "bootstrap" resistor from VM to nSLEEP. *Then* it working, kind of. However this will breach the specifications as the voltage at nSLEEP should not be higher than AVDD.

This probably means we are in a deadlock situation and your application suggestion won't work.

Best regards,

Ralf

Hi Ralf,

Understood,, then we need to disable sleep.

Configure device as Standby always or use external signal to control sleep pin.

Thanks and Best regards

Venkatadri S

Hi Venkatadri,

what do you mean by configuring the device as "standby always"? What you you mean by "disable sleep"? 

I tried the following: I added a 300k resistor between VM and nSleep, pulling nSleep above V_IH (1.6V for nSleep), effectively "bootstrapping" the MCT8316ZT, therefore bringing AVDD and thus my MCU to life. See below

This works at least as a temporary work-around

Would that be a solution?

If yes, please confirm. Thanks!

Regards,
Ralf