LP38502-ADJ: Can this part support 4.85V/600mA output from 5V/900mA input?

Manimaran Kanesan

Part Number: LP38502-ADJ
Other Parts Discussed in Thread: TPS7A52

TI,

I am looking at this part LP38502-ADJ, Linear Voltage Regulator IC 1 Output 1.5A 8-WSON. This part is recommended be WEBench and other TPS parts.

Can this part support 600mA and 4.85V output current and voltage from an input of 5V and 900mA?From the datasheet it seems able to support this spec but like to confirm this viable. Or do you recommend any other part? no switcher pls.

What is the voltage dropout at this output?

And what is the different between TPS and LP parts?

BRgds

over 4 years ago

0 JCHK over 4 years ago

TI__Mastermind 44790 points

HI Manimaran,

Looking at the datasheet, this 5 to 4.85V at 600mA, would be marginal, and the device would be in Drop-out which means it would not have any effective PSRR. Our new TPS7A52 has a much lower drop-out and might be a better choice for this application. Under your load conditions, the drop-out would be ~67mV with the TPS7A52 (it is 150mV with the LP38502).

The LP parts are a series of parts we inherited after acquiring National Instruments. The TPS parts are all designed and developed by TI.

I hope this helps.

0 Manimaran Kanesan over 4 years ago in reply to JCHK

Intellectual 460 points

Hi John,

Thanks for the reply and the suggested part.

TPS7A52 seems suite the design. There is charge pump in the LDO and this is the need for large cap (47uF). The LDO for WiFi an BT application, the concern is, is there any charge discharge time for the cap that can effect the supply to the RF Front end transmission. (Is this part suitable to power RF Front End?)

The part is not available in Mouser or Digikey, am I correct on this? there is direct but from TI.

BRgds

0 JCHK over 4 years ago in reply to Manimaran Kanesan

TI__Mastermind 44790 points

Hi Manimaran,

We designed this low noise part for RF power. So yes it is suitable. As for charging up the output capacitor, We have the following equation to estimate the startup time:

We do have a PG pin that can be used to enable the RF circuit once the voltage is in regulation.

As for discharge, It really depends on your circuit and load.

I hope this helps.

0 Manimaran Kanesan over 4 years ago in reply to JCHK

Intellectual 460 points

Hi John,

All good, just on the Digikey and Mouser availability, do yo know when it will be available?

BRgds

0 JCHK over 4 years ago in reply to Manimaran Kanesan

TI__Mastermind 44790 points

Hi Manimaran,

The RSP package just released a few weeks ago and currently only available on TI.com. The good news is the TI now offers direct pricing so the pricing you see on TI.com should be cheaper than any of our distribution partners.

Regards,

0 Manimaran Kanesan over 4 years ago in reply to JCHK

Intellectual 460 points

Thanks John for the good info. I will close this discussion.

0 Manimaran Kanesan over 4 years ago in reply to Manimaran Kanesan

Intellectual 460 points

Hi John,

Sorry I thought I can close this, do you have Altium footprint and schematic symbol for this part, TPS7A52 .

BRgds

Manimaran

0 JCHK over 4 years ago in reply to Manimaran Kanesan

TI__Mastermind 44790 points

HI Manimran,

Here is what I could find. You may need to modify it.

TPS7A52_RPS_package.intlib.zip

I hope this helps.

Power management

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LP38502-ADJ: Can this part support 4.85V/600mA output from 5V/900mA input?