BQ27Z746: BQ27Z746 ENAB wakeup threshold observed higher than datasheet spec

Tom Tsao

Part Number: BQ27Z746

Tool/software:

Hi TI Team,

We are testing the ENAB wakeup function on the BQ27Z746 using the EVM.
The datasheet specifies that the ENAB pin voltage must be pulled below 0.4V to wake up the device from Shutdown mode.

However, we modified the EVM resistor R26 from 51kΩ to 470kΩ. With this modification, when pressing the switch, the ENAB pin voltage only drops to about 1.2V, and we still observe that the device wakes up (confirmed from PACK output).

CH1: ENAB pin voltage ≈ 1.2V after pressing switch
CH3: PACK output voltage shows device wakes up from Shutdown

Could you please clarify why the device wakes up at around 1.2V on the ENAB pin instead of below 0.4V as specified in the datasheet?

Thanks for your support.

4 days ago

0 Alan Frias 3 days ago

TI__Mastermind 25225 points

Hello,

This question has been assigned and will reviewed when possible, in the meantime please attach your .gg/.log associated with the project.

Thank you,
Alan

0 Jonny 3 days ago in reply to Alan Frias

TI__Mastermind 24741 points

Hello,

The 0.4V spec in the datasheet is the recommendation across all temperatures. It is possible that the device wakes at higher voltages, but this is not guaranteed across temps. Thus we spec 0.4V as this covers all temperatures.

Regards,

Jonny.

Power management

Power management forum

BQ27Z746: BQ27Z746 ENAB wakeup threshold observed higher than datasheet spec