Current consumption numbers - TCXO included\not included

[viola]

Hi,

I have several questions regarding current consumption numbers as they appear in the Datasheet of the STM32WLE5.

in Table 28 / Table 29 the current consumption of LORA RX/TX modes is mentioned.

I have several questions:

1. is it possible to use a TCXO on board and not supply its VDD=1.8V from PB0_VDD_TCXO pin , supply it from an external on board LDO instead?

2. if i chose to supply the TCXO VDD from PB0_VDD_TCXO pin - does the current consumption numbers ,that appear in table 28/Table 29 , include this current consumption ?  if not - what is the delta current for this in each power state (RF RX , RF TX , RF not used) ?

3. is the internal on chip  regulator that supply the PB0_VDD_TCXO - an LDO or SMPS ?

Thank you,

Viola

[viola]

Hi ,

Any update regarding those issues?

Thank you,

Viola

[STTwo-32]

Hello @viola 

1- Yes, you can. The TCXO supply can be provided by the STM32WL on PB0/VDDTCXO or independently to save one GPIO. Keep in mind that the HSEBYPPWR bit 23 of RCC clock control register (RCC_CR) is set and cleared by software to control the function on package pin
PB0-VDDTCXO. 0: PB0 selected; 1: VDDTCXO selected.
In addition, the voltage to apply depends on TCXO selected. Also, in that case, you’ll have a static power consumption, even when 32MHz is not needed.

2- No, table 28/29 are based on a XO oscillator. Add 1.5mA (when 32MHz runs) if TCXO is used.

3- This is an LDO, with a programmable voltage.

Best Regards.

STTwo-32

[viola]

Hi ,

you mentioned I need to add 1.5mA due to the TCXO consumption.

1. Do you assume that the external TCXO requires 1.5mA and thats the reason you mention 1.5mA ?

or    ,      1.5mA is the additional current required by the STM32 VDD and its in addition to the current  required by the exteranl TCXO VDD ?

2. what is the static additional current ,that you mentioned , required by the STM32 VDD when not using the 32Mhz ?

Thank You very much!

Viola

[viola]

Hi ,

Any update regarding those issues?

Thank you,

Viola

[STTwo-32]

Hello @viola 

1. The 1.5mA is coming from the average current consumption from the TCXO itself
2. Concerning the static additional current required by the STM32 VDD when not using the 32Mhz, it is difficult to answer as it is depending on the schematic application. If you want to do it, you may can contact directly your FAE with a ready to use design or do it on your own.

Best Regards.

STTwo-32