LMX2615-SP: LMX2615-SP

singam vamshi krishna

Part Number: LMX2615-SP
Other Parts Discussed in Thread: MSP430F5529

Hello Texas Team,

I have used LMX2615 PLL chip and used it to generate X band frequency. I don't know why the current is not drawing, I mean initially it is drawing about 0.2A when it is powered on and fed with reference frequency, but once I load the register values there is no change in the current drawn and thus no output frequency. I have monitored the voltage at the IC pin and it is 3.3V. Could you please address this issue.

over 3 years ago

0 Noel Fung over 3 years ago

TI__Guru** 107110 points

Hi Singam,

After Vcc power up, if you program POWERDOWN = 1, will the current drop?

0 singam vamshi krishna over 3 years ago in reply to Noel Fung

Intellectual 775 points

Yes even after POWERDOWN = 1 the issue haven't resolved. I have unchecked and checked the dialog box, but there is no change in the current drawn. I have even monitored the output by tapping near the IC pin I mean nearby RFoutAP using open ended cable, but there is not output in spectrum analyzer.

0 Noel Fung over 3 years ago in reply to singam vamshi krishna

TI__Guru** 107110 points

Hi Singam,

I am not clear here. So making POWERDOWN = 1, did you see a significant current drop?

0 singam vamshi krishna over 3 years ago in reply to Noel Fung

Intellectual 775 points

I don't see any change in the current drawn by making POWERDOWN = 1. I have checked continuity in all the traces and everything is fine.

0 Noel Fung over 3 years ago in reply to singam vamshi krishna

TI__Guru** 107110 points

Hi Singam,

Can you see valid signals in the SPI interface? What is the SPI clock rate?

0 singam vamshi krishna over 3 years ago in reply to Noel Fung

Intellectual 775 points

Actually I haven't monitored any SPI signals. I have interfaced Ref pro board which comes with EVM. Moreover the controller used in Ref pro board is MSP430F5529, running at clock rate of 84 MHz.

0 Noel Fung over 3 years ago in reply to singam vamshi krishna

TI__Guru** 107110 points

Hi Singam,

You were using TICS Pro and the Ref PRO board to communicate with the EVM, that is good.

In TICS Pro, on the bottom right corner, did you get a green connection mode? If it is red, an update to the firmware of Ref PRO board may be required. See the EVM user's guide for how to update the firmware.

Clock & timing

Clock & timing forum

LMX2615-SP: LMX2615-SP