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LM5008, LM5018 missing information

Yash Rajwade
Prodigy 80 points
Other Parts Discussed in Thread: LM5018, LM5008, LM5019

Hi,

I was doing a power loss analysis for LM5008 and LM5018 designs (57V input, 12V 0.25A output at 300kHz frequency), and I found below information missing from datasheets-

1. Operating currents when device is powered off internal linear regulator.

2. High side and low side Rds(on) characteristics.

3. Dead time operation in LM5018.

4. Is it recommended to use parallel Schottky across low side mosfet for LM5018?

Can you please provide me required data?

Thanks,

Yash Rajwade. 

  • 0
    TI__Genius 11490 points
    Hi Yash,

    Can you clarify whether you want 1 for LM5008 or LM5019? It is usually good to seperate the question when two different part numbers are involved.

    Regards,
  • 0 in reply to Vijay86929
    TI__Genius 11490 points
    3. Do you want to know the deadtimes?
  • 0
    TI__Genius 11490 points
    4. There is no need to parallel schottky diodes across the low side FETs.
  • 0 in reply to Vijay86929
    TI__Genius 11490 points
    I have copied product engineer to provide this data.
  • 0
    TI__Intellectual 2320 points
    Hello Yash,

    Sorry for the delay in response.

    We do not have the Rds,on vs Temp curve for the LM5008 at present. However, the Rds,on Switch characteristics in the EC table should give you the idea of the variation over temperature.

    Are you looking for the Vcc vs Icc curve (for the device operating current). We do not have a curve for it right now but I can get you the data if required. The Vcc current limit is set at 9.5mA (typ.). Ideally the Vcc will be regulated at 7V typically for Icc < 9.5mA. For Icc >9.5mA, the internal bias regulator will be current limited.

    Regards,
    Sourav
  • 0 in reply to Sourav.Sen
    Prodigy 80 points
    Hello Sourav, Vijay,

    I need below data for LM5018-
    1. Operating current when device is powered from internal linear regulator, along with variation w.r.t temperature and Vin.
    2. Rds on characteristics for high side and low side FETs, with variation w.r.t drain current and temperature. (In datasheet, Rdson is given at Id=200mA)
    3. Deadtime rise and fall, in order to calculate conduction losses in low side body diode.

    Kindly let me know if any inputs from my side are needed.

    Thanks,
    Yash.
  • 0 in reply to Yash Rajwade
    TI__Genius 11490 points
    Hi Yash,
    1. The maximum is in the datasheet. Isn't that what is important. BTW I am trying to find if the variation data is available.
    2. Same comment as for 1.
    3. The planned deadtime is close to 40ns. The one seen at the SW node is dependent on load, VIN etc.
  • 0 in reply to Vijay86929
    Prodigy 80 points
    Hi Vijay,

    1. Operating current in datasheet is for external Vcc supply (Fig. 4, Pg.7). Can I consider the same data for internal regulator Vcc supply also?
    2. I am ok with using max values of Rds (on) from datasheet.
    3. I will use 4.ns as deadtime.
    4. Added request- Can you provide me a Open/Short Pin Protection report for LM5018?

    Thanks,
    Yash.