TPS22968 / Slew rate calculation at Vbias=2.8V

S.Satoshi

Hi,

Please let me ask about formula to calculate slew rate. I found following thread and understand that the formula in datasheet can be used at only Vbias=5V.

Then I'd like to know the formula at Vbias=2.8V because my customer has considered to use with VIN=2.8V and so want to connect VBIAS to VIN.

Best Regards,

Sonoki

over 9 years ago

0 Aleksandras_Kaknevicius over 9 years ago

TI__Genius 15770 points

Hi Sonoki,

Using data previously collected at VIN=VBIAS=2.5V, I was able to come up with the below equation:

SR = 0.71 * CT + 0.915

At CT = 33000pF, the slew rate is about 23431, very close to the 23500 you calculated at VIN = VBIAS = 2.8V. Therefore, this equation should be close enough to estimate the CT capacitor at 2.8V.

Thanks,

Alek Kaknevicius

0 S.Satoshi over 9 years ago in reply to Aleksandras_Kaknevicius

Guru 21685 points

Hi Alek,

Thank you for your information. I believe that this equation was prepared from actual test result. Then was the test condition the same with table 1 as below?

Best Regards,

Sonoki

0 Aleksandras_Kaknevicius over 9 years ago in reply to S.Satoshi

TI__Genius 15770 points

Hi Sonoki,

You are correct, the conditions are the same except VBIAS = 2.5V.

Regards,

Alek Kaknevicius

Power management

Power management forum

TPS22968 / Slew rate calculation at Vbias=2.8V