TPS562231: Power management forum

Part Number: TPS562231

Tool/software:

Hi,

I have following 3 questions about bode plot measurement for TPS562231

1. If we tried to obtain bode plot of TPS562231, Is it correct way below?

2. DCAP3 has one pole and one zero at low frequency to improve DC accuracy, but I think they also make the phase margin lower at low frequency.
Is there any possibility that it leads instability at low frequency?

3. When measured the bode plot, sometimes we can see the result that the phase graph at low frequency seems instable as follows.

Is it caused by noise?

Thanks,

6 months ago

0 Andy Chen 6 months ago

TI__Mastermind 34835 points

Hi,

1. this is correct way

2. There will no instability issue if you follow the recommendation on data sheet for proper L/C value

3. the open loop gain is very high 60~80dB at low freq range (<10KHz), which means the noise on FB is attuned to 1/100~1/1000 of injected noise level, the signal-noise ratio is too small and cause the curve unsmooth, you can average it by multi time or use variable inject noise level.

0 Go 6 months ago in reply to Andy Chen

Genius 4220 points

Hi, Andy

Thank you for your comment.

I’d like you to review customer's schematic and bode plot.

Is it okay to contact you through private message?(because we cannot post these confidential information on open forum...)

or it would also be great if I can contact you via e-mail.

Thanks

+1 Andy Chen 6 months ago in reply to Go

TI__Mastermind 34835 points

OK, send email to me at andy.chen@ti.com

0 Go 6 months ago in reply to Andy Chen

Genius 4220 points

Hi, Andy

Did you already received my e-mail?
I'm really sorry to rush you, but it would be very appreciated if you could share us your opinion by today...

Thanks,

+1 Andy Chen 6 months ago in reply to Go

TI__Mastermind 34835 points

Did you receive any reject email information? so far I didn't receive your email to my box: andy.chen@ti.com

0 Go 6 months ago in reply to Andy Chen

Genius 4220 points

Hi, Andy

I didn't receive any reject message, seemded to send e-mail correctly...

I'll resend the e-mail to you. and send private message on E2E.

0 Go 6 months ago in reply to Go

Genius 4220 points

Hi, Andy

I sent you private message, did you receive it?

+1 Andy Chen 6 months ago in reply to Go

TI__Mastermind 34835 points

Hi Go,

I got your email, will close this thread and discuss it in email.