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Last seen: 5 years 10 months ago
Joined: 2016-03-03 15:01
14681 external flash write


is it posible to write into the external Flash when VBAT is 1.7V and the flash is powered by V33? A flash needs 10mA to perform a write cycle.


Last seen: 1 year 9 months ago
Joined: 2015-06-08 11:34
Hi ronald,

Hi ronald,

If the VBAT is 1.7V the V33 will be slightly less than 1.7V as the 1V8 and 1V8P too. If the 1.7V is within the operational limits of the FLASH it should work, if not (e.g. if this is a 3.3V FLASH) it will not work. Please also note that if the VBAT is 3.3V-4.5V then the V33 will be 3.3V. If the attached FLASH is 1.8V it will be damaged at this voltage

Also you might want to consider to use 1.8V FLASH, as the 1.8V FLASH are consuming less power than the 3.3V. Most of the 1.8V FLASH can work down to 1.65V and the FLASH manufacturers trend is toward 1.8V. Please note that for VBAT1< 2.45V the DC-DC efficiency is lower than the LDOs.

In any case, if the battery is able to supply the required mA, each of the 1V8, 1V8P and V33 can supply up to 75mA in active mode and up to ~3mA in sleep mode.

So it is OK to supply your FLASH from any of the available rails.

Also the please dont post 58x or 68x related questions in the OpenThread section, besides the fact that your question might not be answered (i ve seen your post accidentaly) each thread should be posted on relevant topics.

Thanks MT_dialog