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LM317L-N: Wants to know LM317L-N basic chars.

Koki Tsushima
Intellectual 875 points
Part Number: LM317L-N
Other Parts Discussed in Thread: LM317-N

Dear experts,

This is Koki Tsushima. I want to know LM317L-N ( DSBGA). chars.

Could you answer following questions?

  1. What is Iq (quiescent current)?
    1. Is it same for adjustment pin current? (50uA typ., 100uA ,max)
  2. What is the meaning of max of adjustment pin current charge = 5uA?
    1. Does it mean that Iq can be increased up to 5uA when charge?
  3. Do you have some target of start up time (mV/msec)?
    1. I am asking this question because of audio application.
  4. I am understanding that there are no soft start function of this device. Is it OK?

BR, 

Koki Tsushima

  • 0
    TI__Genius 12675 points

    Hi Tsushima-San, 

    For LM317-N, yes Iadj is the same as the Iq. 

    I believe you mean "change": 

    I believe this means how much the ADJ current will change given the conditions on the ROC. I will have to fin out if this is a +- change or what exactly the max 5uA current refers to. 

    When you say target start-up time, are you referring if we have a min-max time? 

    We do not have this information, however, the startup time depends on several factors and there is the following application as an example if a slow turn on is desired: 

    This device does not have a soft start, however, the soft start functionality highly depends on your system and your needs. If soft start is needed, we have an application note that describes different circuitry that can help: 

    Soft-start circuits for LDO linear regulators (ti.com)

    Best, 

    Edgar Acosta

  • 0 in reply to Edgar Acosta1
    TI__Intellectual 875 points

    Hi Edgar-san,

    Thank you for your kind. Most of question can be closed.

    For start up time, I want to know just one of example.

    I am understanding that it should be diff at several device / circuit situation.

    Don't you have some EVM test data? OR data at Fig22.?

    Any data can be helpful because customer is in early stage to select candidate LDOs.

    BR, Koki Tsushima 

  • +1 in reply to Koki Tsushima
    TI__Genius 12675 points

    Hi Tsushima-San, 

    I am currently looking if we have any data available, this is a legacy device and a very old one as well, some of the data for these type of devices are harder to find.

    If not, then I will go and see if we have samples available to populate an EVM, but this will take me some time to get the measurements, and it will not be a circuit like figure 22, but more of a simpler circuit like the one shown next: 

    Furthermore, since stat up time is not a spec listed on the DS it will not be a guaranteed spec. This will solely provide some insight to give an idea. 

    Best, 

    Edgar Acosta

  • 0 in reply to Edgar Acosta1
    TI__Intellectual 875 points

    Hi Edgar-san,

    Thank you for reply.

    So could you measure start up time?

    I will e-mail you the I, V request later and this E2E is closed.

    BR, Koki Tsushima