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epoulsen
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32KHz vs internal 10KHz clk

Hi 

For the low power mode in the 14585 chip ther is two options using an external 32 KHz or use the internal generated 10 KHz. In our design the 14585 run in BUCK mode and use Lithium coin cells as supply.

So in this setup do I gain anything with adding a 32KHz crystal instead of using the internal generated 10KHz?

Br Erik

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PM_Dialog
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Hi epoulsen,

Hi epoulsen,

Either an external 32 KHz XTAL or the internal RCX can be used a Low Power Clock (LPC).

In case of the external XTAL, please see section 5.3 from the AN-B-054: DA14585/586 Application Hardware Design Guidelines to find the specification.

Regarding the SW, the LPC can be configured from CFG_LP_CLK macro in da1458x_config_advanced.h file.

Thanks, PM_Dialog

epoulsen
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hi 

hi 

thanks but what is the benefit to use the external 32 KHz in this mode if there is any?

Br Erik

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Hi epoulsen,

Hi epoulsen,

The external crystal oscillator is more stable. According to the datasheet the accuracy of the RCX is +- 500 ppm and the accuracy of an XTAL is +- 250 ppm. Since you are using the DA14585 you can use the RCX.

Thanks, PM_Dialog