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Minimize startup current consumption for BLE application on nRF51832

kevinlam

Hello,

According to below thread, we could choice 16MHz external crystal with minimal “startup” current consumption:

https://devzone.nordicsemi.com/f/nordic-q-a/1657/how-to-minimize-current-consumption-for-ble-application-on-nrf51822

The thread seems closed, would you please provide more information about how to choice 16MHz external crystal?

I'm now facing a problem is that, I'm using a power supply 3.3V with limited current output (max 4mA), it is not able to power up 52832, except choice 16MHz external crystal, any other way that I can minimize the startup current?

Thanks and regards,

Kevin

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  • +1

    Hi,

     

    I'm now facing a problem is that, I'm using a power supply 3.3V with limited current output (max 4mA), it is not able to power up 52832, except choice 16MHz external crystal, any other way that I can minimize the startup current?

    There's a mix of nRF51 and nRF52 in your inquiry. Do you use nRF51x22 or nRF52832?

     

    Note that the nRF52-series devices uses 32 MHz crystal.

     

    I'm now facing a problem is that, I'm using a power supply 3.3V with limited current output (max 4mA)

    I'm assuming you're using nRF52832.

    We do not have a specific guide on how to minimize the startup current, as this is usually application specific behavior. In terms of the startup of the clock sources, the time it takes to start up an external clock depends on the type of crystal used. We do not have a table or other data on different manufacturers crystals timing parameters with our devices, but a rule of thumb is that a physically larger crystal starts up faster than the smaller form factor crystals.

    For 32k crystal, these are very slow to start up in general (>0.2 sec), but in return its more accurate than using the 32k RC oscillator.

    You can consider using the DCDC to lower peak currents.

     

    Kind regards,

    Håkon

Reply
  • +1

    Hi,

     

    I'm now facing a problem is that, I'm using a power supply 3.3V with limited current output (max 4mA), it is not able to power up 52832, except choice 16MHz external crystal, any other way that I can minimize the startup current?

    There's a mix of nRF51 and nRF52 in your inquiry. Do you use nRF51x22 or nRF52832?

     

    Note that the nRF52-series devices uses 32 MHz crystal.

     

    I'm now facing a problem is that, I'm using a power supply 3.3V with limited current output (max 4mA)

    I'm assuming you're using nRF52832.

    We do not have a specific guide on how to minimize the startup current, as this is usually application specific behavior. In terms of the startup of the clock sources, the time it takes to start up an external clock depends on the type of crystal used. We do not have a table or other data on different manufacturers crystals timing parameters with our devices, but a rule of thumb is that a physically larger crystal starts up faster than the smaller form factor crystals.

    For 32k crystal, these are very slow to start up in general (>0.2 sec), but in return its more accurate than using the 32k RC oscillator.

    You can consider using the DCDC to lower peak currents.

     

    Kind regards,

    Håkon

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