TPS54519: PG delay time spec

Ella KIM

Part Number: TPS54519
Other Parts Discussed in Thread: TPS62867

Hi team,

I wonder the PG delay time spec of TPS54519. (delay time of PG response after Vout exceeds PG trip threshold) I guess it should respond immediately as it's operating with a comparator, but could you check the spec?

over 3 years ago

+1 Dorian Brillet de Cande over 3 years ago

TI__Genius 14876 points

Hello Kim,

There is no delay time or deglitch time mentioned, so PG will react immediately.

For instance, you can see this in figure 32 in the datasheet.

Let me know if you have further questions!

Thanks,

Dorian

0 Ella KIM over 3 years ago in reply to Dorian Brillet de Cande

TI__Expert 4012 points

Hi Dorian,

Thank you for your response. Could you tell me why PWRGD is triggered before VOUT ramps up in the figure 32?

+1 Dorian Brillet de Cande over 3 years ago in reply to Ella KIM

TI__Genius 14876 points

Hello Ella,

You have to consider VIN is slowly ramping to its final value 5V.

When VIN is below the UVLO the internal circuitry does the required power to drive the PWRGD to the intended value.

The PWRGD behavior when VIN<UVLO is not defined.

Let me know if you have any further questions!

Regards,

Dorian

0 Ella KIM over 3 years ago in reply to Dorian Brillet de Cande

TI__Expert 4012 points

Hi Dorian,

Customer needs more details for the PG timing. Could you please check the latency that PG pin becomes high-impedance after it's triggered?

0 Dorian Brillet de Cande over 3 years ago in reply to Ella KIM

TI__Genius 14876 points

Hello Ella,

We do not test this item in production and is not specified in our datasheet.

Customer can order a TPS54519EVM if needed to verify the PG behavior of TPS54519.

I recommend also you have a look at the newer and easier to implement, TPS62867.

TPS62867 has a Power Good deglitch delay specified of 34us.

Thanks a lot!

Regards,

Dorian

0 Ella KIM over 3 years ago in reply to Dorian Brillet de Cande

TI__Expert 4012 points

Thanks, Dorian.

Having said that the newer devices like TPS62867 has a deglitch circuitry for a stable operation but TPS54519 doesn't have. Therefore for TPS54519, the PG pin latency solely depends on comparator's response time, which is almost immediate (<10us). Please let me know if any misunderstanding here!

+1 Dorian Brillet de Cande over 3 years ago in reply to Ella KIM

TI__Genius 14876 points

Hello Ella,

The deglitch circuitry allows more time for PG to change behavior to avoid glitches and make sure the change is a confirmed one.

Your understanding is correct.

Thanks,

Dorian

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TPS54519: PG delay time spec