AWRL1432: architecture of AWRL1432

Jimmy Gong

Expert 3600 points

Part Number: AWRL1432
Other Parts Discussed in Thread: LMR33630, LMR33630-Q1, TCAN11623-Q1, TPS628502

Hi team,

thanks for your support always. would you please help me to evaluate the architecture below can be achieved or not?

LMR33630-Q1 wide Vin buck will add low pass filter at output to reduce ripple. would you please help to check the LMR33630's spec can meet AWRL1432's spec at 1.8Vin?
tcan11623-Q1 is including 3.3V(70mA max) LDO that can provide for AWRL1432 to communicate between TCAN and AWRL. would you please help to check 70mA max is enough?

BR,

Jimmy

over 1 year ago

0 Cesar over 1 year ago

TI__Guru*** 140594 points

Hi,

Please let us know what is the application for AWRL1432 so that we can assign this to the right support team

thank you

Cesar

0 Jimmy Gong over 1 year ago in reply to Cesar

TI__Expert 3600 points

Hi Cesar,

This case is for ADAS application's SRR radar.

BR,

Jimmy

0 Josh Wyatt over 1 year ago in reply to Jimmy Gong

TI__Guru* 91166 points

Dear Jimmy -

To use this regulator in BOM optimized mode, the integrator needs to leverage the detailed instructions in the LMR33630-Q1 datasheet (section 9.2.2, starts on page 19) regarding choice of operating frequency and ripple filtering, so as to meet the table on the topic, located in the AWRL1432 datasheet. (below)

The peak current requirements per rail are in AWRL1432 DS, on pages 22 and 23, and look to exclude the regulator capability available from the TCAN part.

0 Jimmy Gong over 1 year ago in reply to Josh Wyatt

TI__Expert 3600 points

Hi Josh,

Actually I have asked similar question at e2e before as below link. since I have no idea to judge how much ripple will be reduce when I add filter at buck's output. Do you have any idea for this condition? or I can only choose buck solution according to tps628502 which has successful case.

(8) AWRL1432: Noise and Ripple Specifications - Sensors forum - Sensors - TI E2E support forums

BR,

Jimmy

+1 Josh Wyatt over 1 year ago in reply to Jimmy Gong

TI__Guru* 91166 points

Jimmy -

On page 21 of the LMR33 datasheet, after designer completes steps for choosing the correct L and C for the switcher, there is a formula for calculating ripple, before building circuit, so the correct/at least great starting values can be chosen from the beginning and an expected mVpp level would be established to check after construction.

With regards to the other post - I would agree with everything said there, too.

Additionally, I went onto the online WEBENCH from the product page.

The frequency on this design is 1.4MHz, and has a ripple of of 3.49mV, which is right over the edge for this frequency of operation. This will give a starting point, too and you/they can work formulas in DS from here, to get where is needed or choose another topology, as discussed in detail on the other post.

webench.ti.com/.../8