IWR6843: iwr 6843

user6069030

Part Number: IWR6843

hi,

What is the output impedance of the chip(iwr6843)? The phase of chip pin seems inconsistency,what causes this phenomenon? The phase of erery antenna is the same.

over 5 years ago

0 Akash Gondalia over 5 years ago

TI__Guru 50240 points

Hi User,

I've asked an expert to look into this and we should have an answer for you in the next few days.

Cheers,

Akash

0 CHETHAN KUMAR Y.B. over 5 years ago in reply to Akash Gondalia

TI__Mastermind 25835 points

Hi,

Could you please provide some context here for the above question?

Which ball's output impedance you are looking for?

Do you have some measurement results, could you please provide more details such as setup info, EVM/Custom hardware used, SDK/mmWave studio used.

Thanks and regards,

CHETHAN KUMAR Y.B.

0 CHETHAN KUMAR Y.B. over 5 years ago in reply to CHETHAN KUMAR Y.B.

TI__Mastermind 25835 points

Hi,

Could you please respond to above requests?

Thanks and regards,

CHETHAN KUMAR Y.B.

0 user6069030 over 5 years ago in reply to CHETHAN KUMAR Y.B.

Prodigy 60 points

Hi expert:

Question: I want to know the reason for channel inconsistency.

The test consistency of channels of different chips and different channels of chips is not good,

The amplitude and phase are very different, and the range of amplitude changes is 15dB.

What I have done : Confirm the antenna is good by testing,

the chip works

I doubt where the problem might arise：

1、Channel inconsistency caused by chip；

2、Channel inconsistency caused by impedance mismatch between chip and antenna；

What I want to know:

1、How to test and screen the chip, and whether to provide chip testing and screening methods;

2、Can the impedance test report of chip pin be provided;

3、Will the noise, oscillator phase noise and spurious introduced by the external 40m crystal oscillator? If there is noise, oscillator phase noise and spurious, will the performance be affected;

4、Do need to pay attention to chip welding? Will reflow soldering of SMT chip affect it；

5、What should be paid attention to in chip pin connection and how to ensure consistency；

Thanks for your attention and wish your help.

0 user6069030 over 5 years ago

Prodigy 60 points

Hi experts:

Question: I want to know the reason for channel inconsistency.

The test consistency of channels of different chips and different channels of chips is not good,

The amplitude and phase are very different, and the range of amplitude changes is 15dB.

What I have done : Confirm the antenna is good by testing,

the chip works

I doubt where the problem might arise：

1、Channel inconsistency caused by chip；

2、Channel inconsistency caused by impedance mismatch between chip and antenna；

What I want to know:

1、How to test and screen the chip, and whether to provide chip testing and screening methods;

2、Can the impedance test report of chip pin be provided;

3、Will the noise, oscillator phase noise and spurious introduced by the external 40m crystal oscillator? If there is noise, oscillator phase noise and spurious, will the performance be affected;

4、Do need to pay attention to chip welding? Will reflow soldering of SMT chip affect it；

5、What should be paid attention to in chip pin connection and how to ensure consistency；

Thanks for your attention and wish your help.

0 CHETHAN KUMAR Y.B. over 5 years ago in reply to user6069030

TI__Mastermind 25835 points

Hello,

Is the above observation is on the TI EVM or Custom hardware?

Also, did you use the TI tools (mmWave studio, mmWave SDK) or custom matlab/ embedded system code?

If you have designed the customer hardware we need to review various aspect of the design (PCB, substrate, RF transition into PCB, power supply design, clocking, Antenna, manufacturing process, etc..)

For the Radar sensor RF PCB Design, manufacturing and validation care need to be taken during the design, choice of material, fabrication steps etc..

you could refer to below application note.

http://www.ti.com/lit/an/spracg5/spracg5.pdf

Also power supply design (Noise on the supply, filtering requirements need to be considered) you could refer to Power Management Optimizations - Low Cost LC Filter Solution app-note http://www.ti.com/lit/pdf/swra577

And power supply design in the IWR6843 EVM http://www.ti.com/lit/zip/swrr164

You could refer : below E2E thread on the Substrate selection process and Antenna design guideline.

https://e2e.ti.com/support/sensors/f/1023/p/762323/2829124#2829124

1) For the device screening process you could refer to below E2E post.

https://e2e.ti.com/support/sensors/f/1023/p/783774/2929748#2929748

2) Impedance matching of the RF pins are 50 Ohm at the edge of the package (50 Ohm reference plane is at the edge of the package)

Matching of the transmitters (S11) : <-10dB
Matching of the receivers (S11): < -10dB

3) 40 MHz uses crystal on the board, Yes we need to follow certain clock spec requirement as shown below. Also if you use external clock then there is a phase noise requirement that must be followed as this would be used as a reference clock to PLL/synthesizers.

4) Yes, you need follow recommended guideline for the reflow soldering of SMT chip.

Below is the recommended reflow profile for the solder paste.

5) & 6) For more details you could refer to "Flip Chip Ball Grid Array Package Reference Guide" in the below link.

http://www.ti.com/lit/ug/spru811a/spru811a.pdf

Thanks and regards,

CHETHAN KUMAR Y.B.

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IWR6843: iwr 6843