Current Limit Duration Spec

Hi John,

The behavior you describe is essentially correct (see the waveform from the EVM User Guide below) and the ~2.3A limit is in line with the datasheet graph.

Since the spec we guarantee the reliability and performance of the device against is the maximum rated output current (1.5A), we can't make any conclusive statements about the expected impact of indefinite operation at current limit. The device does have some degree of safe operating space protection built in relating power dissipation and device temperature, but this protection feature is not meant to be used as the indefinite nominal operating condition. 

I would not be overly concerned about this specific case of VOUT startup/recovery as it is temporary and relatively brief in nature with respect to long-term mission profile. With that said, maximum current limit time (with degradation to reliability/performance over time) is not something that has been defined or specified. Do you anticipate that it will occur frequently or over long durations in your design?

If you're wanting to play it safe with the addition of external soft start but don't have the space for additional components, could it be possible in your design to implement soft start on the upstream rail that feeds this device? VOUT would essentially follow VIN until reaching its set value at a slew rate controlled by VIN, which could be used to control the max current.

Thanks,

Sarah

Hey John,

One additional thought. The TPS7H1121 seems like it could be a fit for your design. This device has built in soft start functionality and is quite small, which would help with your board space constraints.

Thanks,

Sarah

Thank you Sarah,

  If the power on behavior simulated above were to occur at the following frequencies and time frames do any/all raise concerns:

1.) Once per day, every day for 5 years.

2.) Once per day, every day for 10 years.

3.) 10 times per day, every day for 5 years.

4.) 10 times per day, every day for 10 years.

-John

Hi John,

None of the timeframes you list are overly concerning in terms of acute stress placed on the device during each event.

As I mentioned earlier, potential long term stress this could cause is not something that has been quantified or tested for. The likelihood of major long term stress seems low to me, but since we do not have data or qualification tests to back this up, it is not something we could fully guarantee.

Thanks,

Sarah

Thank you Sarah,

   Looks like the engineering sample part number for the TPS7H1121 has been released but not any flight models, correct ?

If correct, when are the flight part numbers scheduled to be ready for order entry, and what are expected lead times:

5962R2320301VXC, 5962R2320302PYE, TPS7H1121MPWPTSEP

Hey John,

Yes, that's correct. The sample for the ceramic package option is available for prototyping but not any of the flight-grade options yet. 

What is your expected schedule for each of the listed part numbers?

Thanks,

Sarah

Need EDU parts by 01Jan2025, expect to follow up with you later today Re: flight need date.  Thx -John

Hi Sarah,

    Flight part target need date is 01Jan2026, Flight Part Number Preferences are:

1.) Preferred: 5962R2320301VXC

2.) Alternate: 5962R2320302PYE

3.) Backup Alternate: TPS7H1121MPWPTSEP

Are any of the above scheduled for delivery by 01Jan2026 ?

Thanks John,

Your 1st preference (5962R2320301VXC) will likely be available and in stock to order via TI.com by end of this year, so I think there should be no concerns with your Jan 2026 timeline. 

And as you noted, the "/EM" prototyping units are already available on the part's web page. Evaluation boards (EVMs) with the "/EM" units on them are also currently available for this device if it would be useful for prototyping and evaluation purposes.

Happy to help if there are any other questions at the moment. Otherwise, feel free to post again on E2E if further support is needed for this part later in your design process.

Thanks,

Sarah