HMC575 input power to output power does not conform to the datasheet!

Hi there,

I am using the HMC575 evaluation board and I am trying to validate HMC575 for our design. I have a 3 Ghz signal coming in (from a signal generator) and I put that signal through a band pass filter (2.7GHz to 3.1GHz) to clean any extra spurs. I have compensated for the cable loss in my calculations, and I have connected the output of the HMC575 eval board directly to a phase noise analyzer using SMA header. but when I compare my empirical results with the datasheet, I can see that there is up to 12dBm difference in some cases with the output power measured and the power reported in the datasheet.

I can observe that a 3Ghz component is fed through from the input to the output and in some cases, the amplitude of the 3Ghz on the output is a lot more than the 6Ghz component. The following is our empirical results:

Input power (dBm), 3Ghz sine wave

HMC575 output @ 3Ghz (dBm) (Feed-through from the input on the output)

HMC575 output @ 6Ghz (dBm) (desired doubled frequency on the output)

Delta (6Ghz - 3Ghz)

-10

-4.23

-20.84

-16.61

-8

-2.26

-16.1

-13.84

-6

-0.3

-7.67

-7.37

-4

2.03

4.67

2.63

-2

4.83

11.34

6.52

0

6.24

14.99

8.75

2

5.5

16.71

11.21

4

4.86

16.91

12.02

6

5.02

15.82

10.8

8

4.62

13.8

9.18

9

4.06

12.58

8.51

Besides the 3Ghz input feedthrough, you can observe that the output power vs. input power is significantly different from what the datasheet specifies; for instance, according to the datasheet, a -8 dBm input power at 3Ghz, should result in a -4 dBm output at 6GHz. However we observe in our experiments that the 6Ghz output is -16.1 dBm!

For reference, I have included the output signal which is connected to the phase noise analyzer for an input signal at 3Ghz with -2 dBm power:



Clarified table column
[edited by: amir.b at 9:17 PM (GMT 0) on 9 Oct 2019]
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