Power-on Reset problem with REG0

RE: Power-on Reset problem with REG0

thibv — Wed, 16 May 2018 11:04:42 GMT

Thank you Einar, I'll add an external regulator for the next version, and use configuration 5 instead of conf. 4.

RE: Power-on Reset problem with REG0

thibv — Wed, 16 May 2018 11:02:54 GMT

Marking code is QIAAAA, I have the board with me.
I didn't de-solder the chip. We got samples of this version from Nordic.

RE: Power-on Reset problem with REG0

Einar Thorsrud — Wed, 16 May 2018 10:49:22 GMT

Hi Thibv

Erratum 197 and 202 have not been confirmed for The Engineering 0 revision (QIAA-AA0), but you should consider that it is no longer being tested as it has been obsoleted by three subsequent revisions. It will have issues that are not documented for that revision. The DC/DC is non-functional with REG0 on all engineering samples as well as the only production version, revision 1 (QIAA-Cx0).

RE: Power-on Reset problem with REG0

Turbo J — Wed, 16 May 2018 10:42:58 GMT

Did you de-solder the chip from a prerelease DK? These chips where not available otherwise to my knowledge...

Triple-check the revision number, please.

RE: Power-on Reset problem with REG0

thibv — Wed, 16 May 2018 09:15:57 GMT

Hi,

Thank you for your fast response.

Erratums 197 and 202 are not present on revision QIAA-AA0, which is the version I use. But there is Erratum 140 which suggests to use DCDC, which is contrary to Erratum 197.

My VDD bus is connected to an IMU to ensure power supply. I cannot modify it in my PCB. Consumption hit is not a problem for this version. Is there a way to use VDDH (DCDC or LDO), taking account that :

- I cannot unconnect my IMU, who could consume more than 1 mA

- My revision is QIAA-AA0

Thank you for your help,

Thibv.

RE: Power-on Reset problem with REG0

Einar Thorsrud — Wed, 16 May 2018 09:00:04 GMT

Hi,

Sadly, the DC/DC of REG0 is not functional, so your main options are either to use REG0 in LDO mode (and take the current consumption hit) or use an external DC/DC. has several errata. This is documented in erratum [197] POWER: DCDC of REG0 not functional. You should also be aware of erratum [202] POWER: Device does not start up in high voltage mode in case you want to use REG0 in LDO mode.