Tx Analog in Settings

Projects Reference Development Kit
1

Hi All,
I’m trying to connect signal generator to Myriad RF board Analog input ports. What is the common mode voltage and voltage swing to drive them?

2

Hi andrelEe,

LMS6002D Analog inputs require a 0.6V common mode offset voltage with a 300 mVp-p voltage swing for optimum performance.

Andrew,

3

Hi Andrew,
As per LMS6002D datasheet. Analog Tx IQ input signal specification are 250mVpp and common mode voltage of 65mV. Please refer to Table2: General RF specification section of the DS. This is different from what you have mentioned in your reply. Could you please confirm the Tx IQ input signal specification ?

Thanks and Regards,
Subrahmanya K S

4

Hello,
Literally it is the same. CM 650mV and 250mVpp gives the same peak value as CM 600mV with 300mVpp. In this case you SNR would be better.

Rich

5

Hello,
Is the common mode voltage is 600mV or 65mV ? As per LMS6002D datasheet it is 65mV where as Andrew mail and Zipper Development Kit_1 0r5.pdf section #7.1.1 it is mentioned as 600mV. is This a typo in the datasheet ?

regards,
Subrahmanya K S

6

Most likely it is a typo mistake

7

Hi,

For providing external I Q signals for TX what should be the settings of “DAC Internal Output Load Resistor” for optimal performance of Tx path ?

what will be the input resistance of TXINI and TXINQ pins when “DAC Internal Output Load Resistor” = “open circuit” ?

regards,
Subrahmanya K S

8

When you use external signals for TX path, power down the DACs.
You can program the input impedance using “DAC Internal Output Load Resistor” register. I Open state the impedance is high ohmic, recommended value is 200 Ohm

Rich.