LMX2594: Generating 0.5GHz and 1GHz

Ed S.

Part Number: LMX2594
Other Parts Discussed in Thread: LMX2581, CDCE62002,

Hi There,

I am wondering if LMX 2594 can be used to generate two RF Signals: 500MHz and 1000MHz. TICS Pro can be used generate two RF signals with different ratios at the Output ports A and B as long as Fvco is above 7600MHz. For generating signals at the 500MHz and 1000MHz frequency, the Fvco should go below 7600MHz, and, as a result, the FICS Pro highlights the Fvco value in Red as error. Could you please let me know if I can generate generate two RF Signals at the 500MHz and 1000MHz frequencies? If so, please let me know how to work around the issue.

Best regards,

over 6 years ago

0 Hao Z over 6 years ago

TI__Mastermind 18070 points

Hi Ed,

Unfortunately, it is not possible to generate 500MHz and 1000MHz at the same time. Because the two outputs share the same output divider. The only way to generate two different frequencies at the same time is that one output is direct VCO output, and the other is divided down version of VCO. For example, if VCO = 8000MHz and channel divider is 4, then one output can be 8000MHz and the other can be 2000MHz.

VCO cores range from 7500MHz to 15000MHz.

Regards,
Hao

0 Ed S. over 6 years ago in reply to Hao Z

Prodigy 190 points

Hi Hao,

I bought the LMX2594EVM for that purpose last week. I am wondering if you can suggest any other eval board that can generate 500MHz and 1000MHz simultaneously. Please let me know.

Thanks,
Ed

0 Hao Z over 6 years ago in reply to Ed S.

TI__Mastermind 18070 points

Hi Ed,

To generate 500MHz and 1GHz output using LMX families, the VCO frequency needs to cover 1GHz. For example, LMX2581 has VCO frequency of 1880MHz to 3760MHz, so it cannot be used for your application.

I suggest considering our jitter cleaner and network synchronizer families, the outputs can be individually planned. They are more versatile except that the max output frequency is less than 4GHz, but it should be enough for your application.

Please refer to the selection guides:

www.ti.com/.../products.html

www.ti.com/.../products.html

Regards,
Hao

0 Ed S. over 6 years ago in reply to Hao Z

Prodigy 190 points

Hi Hao,

The CDCE62002 sounds its frequency matches with our application between 10.94 MHz and 1175 MHz. I am wondering if I can get two sine-waves at the output sof the EDCE62002 Evaluation board. Please kindly advise.

Best,

0 Hao Z over 6 years ago in reply to Ed S.

TI__Mastermind 18070 points

Hi Ed,

According to the datasheet, the supported output formats are LVDS, LVPECL and LVCMOS. It seems that sine wave can only be obtained using external low pass filter.

Regards,

Hao

0 Ed S. over 6 years ago in reply to Hao Z

Prodigy 190 points

Hi Hao,

I need sine wave and am wondering if you can refer me to a Direct Digital Synthesis (DDS), which LPF is included. Please advise.

Thanks,

0 Hao Z over 6 years ago in reply to Ed S.

TI__Mastermind 18070 points

Hi Ed,

I don't think we have DDS products in our product line (Clock and Timing Systems). Please post a separate question starting with a TI DDS part number (May be a DAC for waveform generation).

Regards,

Hao

0 Ed S. over 6 years ago in reply to Hao Z

Prodigy 190 points

Hi Hao,

It looks like that CDCE62002 is the best option for us.

I am wondering what the procedure is to replace LMX2594 eval board (, which we purchased it recently) with the CDCE62002 evaluation board. Please kindly advise.

Best,

0 Hao Z over 6 years ago in reply to Ed S.

TI__Mastermind 18070 points

Hi Ed,

Sorry we only provide technical support and I don't really know the procedures to return/replace an EVM. Please get help from ti store: http://www.ti.com/info-store/help/ti-store-order.html

Regards,
Hao

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LMX2594: Generating 0.5GHz and 1GHz