BQ76PL455A: Error increased with output cap

Abraham Rashid

Part Number: BQ76PL455A
Other Parts Discussed in Thread: BQ79616

Hi team,

Our customer is using BQ76PL455 and they found voltage sensing error increased after using a 390pF cap between out1 and out2 pins, both negative and positive error exists. Error is smaller if no cap is used. Could you help analyze the reason for this? Thanks!

over 4 years ago

0 Taylor Vogt over 4 years ago

TI__Genius 17370 points

Hi Abraham,

Please refer to this thread as we typically recommend 390pF as this was how we did validation.https://e2e.ti.com/support/power-management/f/196/p/804423/2980172?tisearch=e2e-sitesearch&keymatch=bq76pl455a%2520390pF#2980172 If customer needs to change based on their characterization data, they will need to validate the performance. I recommend transitioning towards bq79606a and bq79616 devices as well.

Do they have some other circuit changes from our recommended schematic in the user guide that may be affecting this performance?

Regards,

Taylor

0 Abraham Rashid over 4 years ago in reply to Taylor Vogt

TI__Expert 3030 points

Thank you, Taylor.

They used 2.2uF/16V not X7R capacitor for VREF, reference design used 1.8uF/25V X7R capacitor. Will this influence accuracy?

0 Taylor Vogt over 4 years ago in reply to Abraham Rashid

TI__Genius 17370 points

Hi Abraham,

It is possible, but if they are choosing 2.2uF for cost I wouldnt expect much variance here. However, we cant guarantee the same specs collected in the datasheet used with 1.8uF.

Regards,

Taylor

Power management

Power management forum

BQ76PL455A: Error increased with output cap