Reset Generator question

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Reset Generator question

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Febins
Contributor I

Hi there, I am trying to answer some question from my company, cannot seem to find the answer for it. We are using S32K118 .

question 1) 

What is the highest voltage that the reset generator tracks Vcc before becoming active (e.g. reset follows the Vcc rail until Vcc reaches 1V)?

Febins_0-1724100702488.png

 

question 2) Is the reset generator slew rate dependent (see figure in 3.2.105 above dv/dt)?  

It would be really helpful if someone can answer this,

thanks

 

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danielmartynek
NXP TechSupport
NXP TechSupport

Hi @Febins,

1.

Out of the power-on reset, the MCU (its PN junctions) is not biased.

So, the reset module cannot control the reset_b until the VDD voltage reaches the forward bias voltage.

Once it can control the reset_b, the pin is asserted and stays asserted until the VDD LVR deassert level is reached.

2.

The ramp rate simply follows the VDD voltage.

 

Regards,

Daniel

 

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danielmartynek
NXP TechSupport
NXP TechSupport

Hi @Febins,

1.

Out of the power-on reset, the MCU (its PN junctions) is not biased.

So, the reset module cannot control the reset_b until the VDD voltage reaches the forward bias voltage.

Once it can control the reset_b, the pin is asserted and stays asserted until the VDD LVR deassert level is reached.

2.

The ramp rate simply follows the VDD voltage.

 

Regards,

Daniel

 

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Febins
Contributor I
1. Can you tell me what is the voltage value of VDD LVR deasset level? thanks
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danielmartynek
NXP TechSupport
NXP TechSupport

Hi @Febins,

There is the assert threshold and its hysteresis specified in the DS.

danielmartynek_0-1725216976623.png

 

BR, Daniel

 

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