LDO for PCIe core and phy power

Sebastian Ciesluk80

Expert 1121 points

Other Parts Discussed in Thread: TPS7A52, TPS7A7001

Hi, In the next design I need to create quiet power for PCIe interfce in the SOC.

The requirements are as follows:

1st power

must be an LDO

Uin1 - switcher output , I can set voltage to whatever I need to lower LDO power

Uout1-0.75V

Iout1 -1.8A

feedback pin(s) needed

good accuracy (1% if possible incl load and line), fast transient good PSRR ( I wil use ferrite on Uin1 so no need for super low PSRR)

2nd power

must be an LDO

Uin2 - switcher output , I can set voltage to whatever I need to lower LDO power, can (must) be different than Uin1

Uout2-1.8V

Iout -0.8A

feedback pin(s) needed

good accuracy (1% if possible incl load and line), fast transient, good PSRR ( I wil use ferrite on Uin2 so no need for super low PSRR)

I would prefer same LDO for both cases to easy manufacturing / sourcing.

All help appreciated - thanks

over 3 years ago

Nick Butts over 3 years ago

TI__Guru 50025 points

Hi Sebastian,

Check out TPS7A52. It almost works for both cases, except that the minimum output voltage is 0.8V instead of 0.75V.

For the other one, TPS7A7001 may be the only option because of the output voltage requirement.

Regards,

Nick

Sebastian Ciesluk80 over 3 years ago

Expert 1121 points

Thanks,

TPS7A7001 seems to have wide accuracy, TPS7A52 is closer so going this route I have found TPS7A8401A. Looks like perfect match, do you know if this one has any drawbacks? I can not find it anywhere available to buy, are you able to confirm if this is planned to be procuced by TI knowing current shortages issues?

Nick Butts over 3 years ago in reply to Sebastian Ciesluk80

TI__Guru 50025 points

Hi Sebastian,

I'm not aware of any issues with this part, and I wasn't able to find any documentation for past customer issues so that's a good sign as well. Let me check with my team about the outlook for supply.

Thanks,

Nick

Sebastian Ciesluk80 over 3 years ago in reply to Nick Butts

Expert 1121 points

Thanks this is good news, will wait for more info.

Sebastian

Nick Butts over 3 years ago in reply to Sebastian Ciesluk80

TI__Guru 50025 points

Hi Sebastian,

It looks like all versions of this device are on backlog, but the TPS7A8400ARGRT has the least.

Do you have a sales representative that can help out here? If you were to place an order now (or soon) then you would at least be put in line instead of waiting for excess supply.

Thanks,

Nick

Sebastian Ciesluk80 over 3 years ago in reply to Nick Butts

Expert 1121 points

Thanks Nick, it must be TPS7A8401 due to low voltage, for prototyping I do the purchases to speed things up, we talking about 164 pcs are you able to state the estimated delivery?

Nick Butts over 3 years ago in reply to Sebastian Ciesluk80

TI__Guru 50025 points

I see. It is not easy to estimate the lead time on this given the current situation because so many devices are on backorder so it is difficult to know when we'll get silicon for each device. Unfortunately the best option is to monitor ti.com and keep checking for inventory.

Regards,

Nick

Sebastian Ciesluk80 over 3 years ago in reply to Nick Butts

Expert 1121 points

Ok , so TPS7A8401 is one option, are you able to sugegst anything else from TI maybe with better availability?

Nick Butts over 3 years ago in reply to Sebastian Ciesluk80

TI__Guru 50025 points

Hi Sebastian,

I am sending you a PM so I am going to close this thread.

Thanks,

Nick

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LDO for PCIe core and phy power