LM317: LDOs that do not have PSRR

Jade Han

Part Number: LM317
Other Parts Discussed in Thread: UA78, TLV761

Hello experts,

For the ICs that do not have PSRR specified in our datasheets, how can we know the PSRR values?

I am going through some of our ICs' PSRR features for customer, to replace competitor ICs. They want us to compare our PSRR with the competitor ICs that they are currently using.

However it seems only some of the ICs have PSRR feature specified, and some do not, like organized in below table. Do we not have any PSRR data for these ICs?

Thank you.

Part Number

PSRR(120Hz)

PSRR(100kHz)

PSRR(10MHz)

KIA7808API-U/PF

58dB

24dB

-8dB

UA7808CKCSE3

40dB

LM317KTTR

62dB

LM317DCYR

62dB

LM7812CT/NOPB

48dB

KIA78L05F-RTF/P

41dB

20dB

-8dB

UA78L05AIPK

58dB

62dB

UA78L05ACPKM3

58dB

62dB

KIA7805API-U/PF

62dB

25dB

-8dB

LM317KTTR

62dB

LM317DCYR

62dB

LM7805CT/NOPB

48dB

S78D50D

70.5

54.1

34.5

TLV76150KVUR

78dB

55dB

30dB

LM317AMDTX/NOPB

80dB

KIA7815API-U/PF

54dB

32dB

0dB

LM317KTTR

62dB

LM317DCYR

62dB

LM7815CT/NOPB

48dB

over 1 year ago

+1 Prakash Lakhit over 1 year ago

TI__Expert 5616 points

Jade,

Please find PSRR graphs in each of the device datasheets. We usually only specify PSRR at 100kHz db.

Regards,

Prakash L

0 Jade Han over 1 year ago in reply to Prakash Lakhit

TI__Intellectual 1595 points

Hi Prakash,

Thank you so much for your feedback and for the comparison table!

Best regards,
Jade

0 Jade Han over 1 year ago in reply to Prakash Lakhit

TI__Intellectual 1595 points

Hi Prakash,

Recently customer says they need PSRR values for 120Hz, 100kHz, and 10MHz in order to compare the performance with our competitor ICs and choose the replacement IC..Right now they are going through the process of comparing and choosing the ICs to replace the EOL LDOs or very old LDOs, and that's why they need this data.

For below ICs, I cannot find PSRR data for 120Hz and/or 10MHz, if you have this data could you please share it with me? If not, customer asks if we can measure the PSRR and share it with them.

LM7805CT/NOPB

LM7815CT/NOPB

UA7812CKCS

LM2940CT-12/NOPB

UA78M05IKCS

TLV76150KVUR

0 Prakash Lakhit over 1 year ago in reply to Jade Han

TI__Expert 5616 points

Jade,

For LM78 and UA78, we don't have this data. These are linear regulators and legacy devices and PSRR was not characterized for these devices.

LM2940 and TLV761 have graphs with the values of PSRR that you need.

LM2940:

TLV761:

Thanks,

Prakash L

0 Jade Han over 1 year ago in reply to Prakash Lakhit

TI__Intellectual 1595 points

Hi Prakash,

Thank you for your response! For the LM78 & UA78, could you please measure the PSRR values for the empty cells of below table?

Currently Samsung Home Appliance is looking for ICs to remove from their AVL list, like how we would EOL the old devices, and are finding replacement ICs.

In order to compare our ICs' performance with competitors', they need these spec. Without it, they would have to interpret it as our ICs to have lower performance..They have other specs, they need this PSRR values. With your help I was able to fill out some, but they say they need all the values..

	PSRR
P/N	120Hz	100kHz	10MHz
UA78L05ACDR
LM7805CT/NOPB
LM7815CT/NOPB
UA7812CKCS
LM2940CT-12/NOPB	75	66
UA78M05IKCS	81	40
TLV76150KVUR	88	55	31

Best regards,
Jade

0 Stephen Ziel over 1 year ago in reply to Jade Han

TI__Mastermind 37025 points

Hi Jade,

We will assign this to one of our application engineers to review and get back to you.

Thanks,

Stephen

0 Juliette over 1 year ago in reply to Stephen Ziel

TI__Mastermind 18466 points

Hey Jade,

Do you have specific output voltages and load currents that you are looking for?

Best,

Juliette

0 Jade Han over 1 year ago in reply to Juliette

TI__Intellectual 1595 points

Hi Juliette,

Could you measure it for 12Vin 5Vout 100mA please?

Thank you for your support.

Best regards,
Jade

0 Juliette over 1 year ago in reply to Jade Han

TI__Mastermind 18466 points

Hey Jade,

I will order LDOs and EVMs to take these measurements. I will let you know when it is complete, or if I run into any issues

0 Jade Han over 1 year ago in reply to Juliette

TI__Intellectual 1595 points

Hi Juliette,

Thank you so much for your support. May I ask by when we could receive the results?

Best regards,
Jade

0 Juliette over 1 year ago in reply to Jade Han

TI__Mastermind 18466 points

I can expect to receive parts and EVMs within the next week so I think 3-5 business days after receiving parts should be ample time.

0 Juliette over 1 year ago in reply to Juliette

TI__Mastermind 18466 points

Hey Jade,

The other parts have not arrived, but here is the PSRR graph for UA78L05ACDR

Note, I was unable to order the UA7812CKCS through our sample system, so I do not think I will be able to take this measurement.

This week is also a holiday, so unless the components arrive within the next two days, these measurements should be complete by next week.

Best,

Juliette

0 Hannah Grace over 1 year ago in reply to Juliette

TI__Genius 15125 points

Hello Jade,

I will be taking over to help facilitate questions on this thread.

Could you please update me on what still needs to be done to answer your questions?

Thank you,

Hannah

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LM317: LDOs that do not have PSRR