USB hosts hubs transceivers Forum Discussions

[TeMa_2997106]

The data sheet of HX2VL has the following description.

The internal reset is initiated, when there is an unstable power event for silicon’s internal core power (3.3 V ± 10%). Internal reset is released 2.7 µs ± 1.2% after supply reaches power good voltage (2.5V to 2.8V).

After starting up to the normal voltage (3.3V), how many volts does the voltage droop before the POR sequence starts again? Doesn't POR start until it droops to 2.5V?

HX2LP has no description in the datasheet, but is it the same rule?

Thanks,
Tetsuo

[TakashiO]

@TeMa_2997106 -san,

Thanks for posting your questions on this community.
I'm checking that to expert and I'll get back to you soon.

I understood what you want to know is recommended HX2LP's POR process, Is this understanding correct?

Thanks,

[TeMa_2997106]

Takashi-san,

I use both HX2VL and HX2LP. Therefore, I would like to know the specs of both.

Thanks,
Tetsuo

[TakashiO]

@TeMa_2997106 -san,

Thanks for your supplementary comments.

Regarding POR, HX2VL has internal POR circuit and works it as you mentioned above.
For HX2LP, it does NOT have internal POR circuit so external and need to apply reset signal externally if Vcc get out of range. This is a background why LP has independent Vbus monitoring pin. 

Thanks,