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Voltage Regulator with Mil Temp -55°C to +125°C for F28335

Fernando Campos
Prodigy 80 points
Other Parts Discussed in Thread: SM320F28335-EP, LMZ14201EXT, TPS74401-EP, TPS70751-EP

Hi!

Working on aircraft product development, and I was wondering if anyone may recommend a voltage regulator that I can use with the C2000 SM320F28335-EP (Dual 3.3V and 1.8V). All my components need to be rated for military temp of -55°C to +125°C.

Thanks in advance.

Fernando C.

  • 0
    Guru 192875 points
    Hi Fernando,

    You can use this part: TPS707xx

    Datasheet:
    www.ti.com/.../tps70758.pdf

    Regards,
    Gautam
  • 0 in reply to Gautam Iyer
    Prodigy 80 points
    Hi Gautam,

    Thanks for your suggestion. Unfortunately this part would not work for me, as it is only rated for TJ = –40°C to +125°C. My project requirements are for all parts to be rated TJ = –55°C to +125°C, since this is for a military product. TI recommends using TPS767D318 with the SM320F28335-EP , however this part is also rated TJ = –40°C to +125°C.

    Would the LMZ14201EXT work, if I use two of these (one for the 3.3V and another one for the 1.8V core supply)? These are 1A SIMPLE SWITCHER Power Module with 42V Maximum Input Voltage for Military and Rugged App. Should I be concerned about the noise of this switching supply?

    Thanks.
    Fernando
  • 0 in reply to Fernando Campos
    TI__Guru 57255 points

    Hi Fernando,

    Without fully comprehending your project, what you suggest seems possible. 

    Two notes:
    1) The 'F28335 chip requires some power sequencing to remove the risk of the device generating glitches on its IO pins during power on.  See the power sequencing section of your datasheet for more info.
    2) As long as the module can guarantee that it's output voltage is within the range required by the datasheet you should be fine for VDD & VDDIO.  I might recommend putting some filtering (perhaps PI filters) between the digital supply inputs for the device and the analog supply inputs in order to increase the accuracy of the ADC.


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    Prodigy 80 points
    Brett,

    Thanks for your feedback. Very good points you bring out. I guess a good alternative would be to do a combined approach:

    1. use the switcher LMZ14201EXT to bring down my input down to ~5V
    2. use two LDO voltage regulators, such as the TPS74401-EP, to generate the 3.3V and 1.8V. This one is nice, since it has Programmable Soft Start, so I can take care of the power sequencing of the F28335 chip, and I won't have to worry about filtering the noise. The only drawback is that I'll have to use two of these regulators.

    By the way, the part that Gautam had recommended has an offering with Extended Temperature (TPS70751-EP), that is a dual LDO regulator with 3.3V/250mA and 1.8V/125mA output. Unfortunately, the F28335 consumes about 320mA! This is way more than what the TPS70751 can source. This is ideal for another processor that doesn't require as much current as the F28334.

    Thank you,
    Fernando