What is the noise spectral density of the voltage outputs that would bias an amplifier?
Would this active bias controller be recommended for a LNA with a Vd = 10V and a Vg = -2.3V?
Please refer to the attached SA shot, which shows the spectrum of the output of the DUT AMP.
Note that the red marked area is due to the Phase Noise of the input signal.
Yes, you can bias an LNA with Vdd = 10V and a Vgg = -2.3V by using HMC920LP5 or HMC981LP3.
For the negative gate voltage, should an external voltage be supplied or is the chip’s own supply sufficient for a device with a 75 mA drain current?
Also, regarding the Over/Under current alarms, the current level thresholds are set by current measurements through the pin 26 and 28 resistors to ground. Is my understanding of this correct?
HMC920LP5E can supply up to 500 mA drain current. So, the drain current requirement of 75 mA is not a problem.
Gate output of HMC920LP5E can sink/source upto +-4 mA, which is more than enough for a DUT AMP with 75 mA drain current, but you should check with the LNA vendor and make sure that Gate current is below 4 mA.
The Over/Under current thresholds are adjusted by the external resistors on PINs 26.27 and 28.
The following formulas can be used to set the values of the threshold levels.
Over current ALM Threshold = Iocth = IDRAIN (1+R14/(R16+R15)),
Under current ALM Threshold = Iucth = IDRAIN (1-R16/(R16+R15)) ,
where R16+R15 should always be equal to 5 kΩ (%1 accuracy)
Retrieving data ...