LM98714: CLKOUT(CMOS mode)

Kuramochi Tadahiko

Guru 28715 points

Part Number: LM98714

Hi,

Though my customer is evaluating LM98714 on the CMOS mode, clock signal does not output from CLKOUT pin(40pin).

DOUT0~7 pin is outputting CMOS signal at 90MHz.

They are setting value into register as attached.

LM98714 register setting.xlsx

Is there another register to change setting?

Please let me know if you have any question.

Best Regards,

Kuramochi

over 5 years ago

0 Aaron Goodson over 5 years ago

TI__Expert 6330 points

Hi Kuramochi,

I have notified our expert regarding this topic. Please expect a response by 1/18/19.

Thanks,
Aaron

0 Kuramochi Tadahiko over 5 years ago in reply to Aaron Goodson

Guru 28715 points

Hello Aaron-san,

How is this situation?

Best Regards,
Kuramochi

0 Costin Cazana over 5 years ago in reply to Kuramochi Tadahiko

TI__Expert 4940 points

Hi Kuramochi san,

Based on register settings, 3 channels are selected with clock multiplication(3x).
In this condition the max INCLK=15MHz. What is the customer INCLK freq?
Also for CMOS Pin 23 should be grounded.

Regards,
Costin

0 Kuramochi Tadahiko over 5 years ago in reply to Costin Cazana

Guru 28715 points

Hi Costin-san,

Thank you for your advice.

>Also for CMOS Pin 23 should be grounded.
If OSB(23) pin shorts to ground, does is mean that mode 2 is selected?

Best Regards,
Kuramochi

0 Costin Cazana over 5 years ago in reply to Kuramochi Tadahiko

TI__Expert 4940 points

Hi Kuramochi san,

LVDS/CMOS input type is internally sensed, if pin is not grounded LVDS may be selected and the LVDS output clock is pin 30 and 31
That's a typo in my previous answer, pin 29( INCLK-) should be grounded, CMOS clock output is pin40(CLOCKOUT/CLK10)

Regards,
Costin

0 Kuramochi Tadahiko over 5 years ago in reply to Costin Cazana

Guru 28715 points

Costin-san,

Though my customer checked above, INCLK=15MHz and pin29 was shorted with GND.
What should we check anything else?

Best Regards,
Kuramochi

0 Kuramochi Tadahiko over 5 years ago in reply to Kuramochi Tadahiko

Guru 28715 points

Costin-san,

How is this situation?

Best Regards,
Kuramochi

0 Costin Cazana over 5 years ago in reply to Kuramochi Tadahiko

TI__Expert 4940 points

Kuramochi san,

Base on the info I got I see no reason why it doesn't output the clock. The ADC can not output data without the reference clock.
All the external signal meet the spec I/O conditions?

Best Regards,
Costin

0 Costin Cazana over 5 years ago in reply to Costin Cazana

TI__Expert 4940 points

Hello Kuramochi san,

After the start scan bit is set( page0 reg2 bit0=1) the SH_R pin needs to be pulse twice. After the second SH_R pulse the internal "BOS" is generated( Figure 38 page 40) and the AFE is properly configured.

Best Regards,
Costin

0 Kuramochi Tadahiko over 5 years ago in reply to Costin Cazana

Guru 28715 points

Cazana-san,

Thank you for your advice.
We'll try it.

Best Regards,
Kuramochi

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LM98714: CLKOUT(CMOS mode)