LMX2595EVM: LMX2595 Ramping

Kailyn Chen

Part Number: LMX2595EVM
Other Parts Discussed in Thread: LMX2595

Hello,

One customer use the LMX2595 to generate the incremental LFM signal which range is 8G ~8.05G. The configuration is as following with TICSpro:

The output is not correctly, please refer to the output:

But when changed the next_ramp of RAMP0 with RAMP1, the output is normal, please for your reference:

So what is the problem? and I am not fully understanding the RAMPing function, could you please help to give me some advice?

Best regards

Kailyn

over 6 years ago

0 Noel Fung over 6 years ago

TI__Guru** 108550 points

Hi Kailyn,

How does the customer want to ramp?

(1) Continuous triangular wave: 8000MHz --ramp up--> 8050MHz --ramp down--> 800MHz --ramp up--> 8050MHz ............

(2) Repeated triangular wave: 8000MHz --ramp up--> 8050MHz; 8000MHz --ramp up--> 8050MHz; 8000MHz --ramp up--> 8050MHz; ........

(3) Single ramp: 8000MHz --ramp up--> 8050MHz (stay at 8050MHz)

0 jinjing zuo over 6 years ago in reply to Noel Fung

Prodigy 230 points

I want get （2）repeated triangular wave

0 Noel Fung over 6 years ago in reply to jinjing zuo

TI__Guru** 108550 points

Hi Jinjing,

Please try check the RST box in RAMP0.

0 jinjing zuo over 6 years ago in reply to Noel Fung

Prodigy 230 points

When the RST was checked，The output is not so good, please refer to the output:

0 Noel Fung over 6 years ago in reply to jinjing zuo

TI__Guru** 108550 points

Hi Jinjing,

I think this is normal because you are forcing it to jump from 8050MHz to 8000MHz in no time before asking it to ramp up again. The synthesizer needs some time to settle from 8050MHz to 8000MHz and therefore, the beginning of the ramp is not stable.

0 jinjing zuo over 6 years ago in reply to Noel Fung

Prodigy 230 points

I see, Thank you very much.

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LMX2595EVM: LMX2595 Ramping