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Using LDO or Switching Converter

Ram Tal
Intellectual 500 points
Other Parts Discussed in Thread: CC1121, TPS62740, TPS62743, TPS82740A, LMZ20502, LMZ21701

Hi,

I wonder if I can get an answer for the subject-

In my circuit for an ear tag application (small PCB 33x37mm) I'm using MCU, CC1121 and additional sensors- MEMS (ADXL362) and Gyro (LSM6DS3).

I want to add REGULATOR to the circuit. which one should I use? I tested the TP62740 but I'm still thinking of an LDO. in addition, for some reason I'm getting 0.1% of crc errors for the packets i'm sending (not happening when I'm transmitting when connected straight from the battery)..

I'm using an Li-MnO2 battery (3.1v) and I want to regulate 2.2v.

Any advice?

Thanks in advance.

  • 0
    Intellectual 500 points
    off course- it's TPS62740. transmitting at 915 MHz. MEMS & Gyro are digital altough analog inside, obviouslly..
  • 0 in reply to Ram Tal
    TI__Guru**** 191445 points
    Since it is a battery powered application, I would be inclined to use a switching regulator. for LDO your starting efficiency is 71% and decreasing as your battery depletes.
  • 0 in reply to JohnTucker
    TI__Expert 7110 points
    TPS62740 family is a great fit for configurations where battery runtime is key.
    Especially for noise it is very important to carefully rout your layout! Did you check on EVM level so far, or do you have a board?
    If there are still noise issues, you can use more output capacitance to reduce the ripple.
    For small solution size, please also check TPS62743 or the module TPS82740A
  • 0 in reply to Florian Feckl
    Intellectual 500 points

    Florian and John, thanks a lot for your comments. Apparently, there was a problem with the tested tag's radio, when I tested other tags I didn't got any CRC errors.

    I'll still have to think what's best for the sensors on the board, LDO or Buck converter BUT a regulate voltage is a must due to the need of regulate voltage for keeping a steady 0g offset.

    Also, as far as I know, for battery operated tags it will be better to regulate the voltage to the MCU and Radio in order to save energy.

    Ram

  • 0 in reply to Ram Tal
    TI__Genius 15810 points
    Hello,
    You could also consider the LMZ20502 or the LMZ21701. These are the new SIMPLE SWITCHER nano modules that are as small as LDOs and much more efficient.
    Regards,Akshay