TPS25840-Q1: Is it mandatory to pull high EN before DP/DM?

Johnny Guo

Part Number: TPS25840-Q1

Hi, team,

Just want to check that EN must be pull high before DP/DM data switch? If DP/DM data switch first then EN pull high, will VOUT fail to start up to 5V?

Thanks.

Johnny

over 2 years ago

0 Kuno Wu over 2 years ago

TI__Mastermind 18556 points

Hi Johnny,

According to my understanding, if you do not pull the EN high, then the VCC will not work, then DP/DM date switch will not work too.

Best Regards,

Kuno

0 Johnny Guo over 2 years ago in reply to Kuno Wu

TI__Expert 4910 points

Kuno,

Do you mean the data on DP/DM will not impact Buck to power up to 5V when EN pulled high?

Thanks.

Johnny

+1 Kuno Wu over 2 years ago in reply to Johnny Guo

TI__Mastermind 18556 points

Hi Johnny,

No, I mean the EN need to pull high, then our internal control model will be power on, then it can open the DM/DP switch. And I guess you may be want to whether there is a timing between the VBUS and DM/DP or not? Yes, you must make sure the DP/DM voltage lower than below voltage before our VBUS power on. The reason is that the DP/DM has a internal parasitic diode to VBUS, and if you add some voltage to DM/DP before VBUS power on, it will charge the VBUS higher than 0.8V, then our device will fail to power on.