i.MX28 VDD4P2 Regulated Output and Absolute Maximum Rating

[george]

Dear all,

We doubt about the description of the following data sheets.

Somebody should tell the correct interpretation.

• The absolute maximum rationg of VDD4P2

• The VDD4P2 output voltage accuracy

Aren't two parameters described above contradictory?

Best Regards,

George

[Yuri]

Maximum DCDC_BATT / BATT value is 4.242 V, including accuracy (of 3 %),
mainly – in order to avoid  maximum charging voltage for  the Li-Ion batteries.

Have a great day,
Yuri

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[Aemj]

Dear Yuri,

Sorry, please let me know a little in more detail.

How meaning are "VDD4P2V" described in the symbol of Table 6 ?

Does it differ from the VDD4P2 internal regulator output?

Best Regards,

George

[Yuri]

  The "VDD4P2V" - described in the symbol of Table 6 - yes, it is VDD4P2 regulator

output, which may be used as input of the internal DCDC converter. In this sense it
should be "close" to DCDC_BAT.

Regards,

Yuri.

[george]

Dear Yuri,

Thank you for the comment.

I have understood the above your comment somehow.

Please let me know a little in more detail only about "Maximum DCDC_BATT / BATT value is 4.242 V, including accuracy (of 3 %)".

The 4.242V seem to be +1%.

BR,

George

[Yuri · Accepted solution]

Really : Maximum DCDC_BATT / BATT / VDD4p2  value is 4.242 V, even including accuracy of 3 % for VDD4p2.

~Yuri.

[michaelkoelbl]

Hello Yuri,

we have an external charger (TI bq24250) which has a SYS-output where it provides a regulated output in case 5V are present. This SYS-output we want to connect do the DCDC_BATT and BATT pins of the iMX28. This voltage is litte greater than the mentioned max value of 4.242V, it can be as much as 4.37V. Is this allowed?

For the sake of completeness: the charger switches the battery voltage to SYS-output as soon as the 5V are gone.

Thanks,

Michael

[Yuri]

Hello,

I am afraid the maximum  value for both DCDC_BATT and BATT is 4.242 V.

This is stated separately for battery charging pin BATT  and for DCDC input

voltage pin (DCDC_BATT) in the Table 6 (DC Absolute Maximum Ratings).
Maximum charging voltage for  the Li-Ion relates to the BATT pin only.

Regards,

Yuri.