I have question about PA_BIAS1,PA_BIAS2,PA_BIAS3,PA_BIAS4 Voltage settings. I could not adjust the voltage level PA_BIAS Gate voltage as -1.5 V. Datasheet says that you can adjust the output voltage ranges from 0 to -4.8 Volt page 10 REV .A . I want to increase the output voltages periodically but I dont understand how I can control the ranges by using the registers which are from 0x046 to 0x047 or for transmit mode from 0x029 to 0x02A. For example, according to datasheet, to adjust the output of PA_BIAS1,it says that you need to write hex 60 into the 0x046 register to make -1.8V in receiver mode but I want to adjust -1.5V how can I adjust it.
There is an 8-bit DAC with a full scale of -4.8V that controls each PA bias output.
A value of 0x00 should translate to 0V, while 0xFF produces -4.8V.
A value of 0x50 should produce about -1.5V.
Okey I tried and I got the different voltage values that are adjusted in multimeter. I wanted to adjust because of the power amplifiers' bias up and down procedure.
If you programmed the above values, how much error did you see?
Remember, register 0x46 is for an PA Bias OFF value, i.e this is the value that PA_BIAS1 will be when the device is in Receive mode and you want the PA to be in an off/debiased state. Please reference Table 18 and the "PA BIAS OUTPUT CONTROL" section in the datasheet for proper control of these bias pins.
Yes I try to did according to table 18 which are BIAS_CTRL=1,TR_SOURCE=1, TX_EN=0 TR input=1, PA_ON=1 and BIAS_CTRL=1,TR_SOURCE=1, TX_EN=0 TR input=1, PA_ON=0 . Unfortunately I did not see the different BIAS_OFF and BIAS_ON values. I saw the all th time same values in Transmit Mode. How can I handle it ?
What voltage values are you measuring at the PA_BIAS1 pins? Is it just 0V?
Have you bypassed the RAM using Register 0x38? If you don't do this it will set the PA_BIASx pins' values from the memory, instead of the registers. Try writing 0x3860 and retesting. This should bypass both the beam data and bias data.
I could not understand between the RAM setting and PA_BIASx pins, because I dont use RAM to store the pahse and amplitude settings. Also I dont load any phase and amplitude setting before I upload I want to see voltage level of PA_BIAS pins. Moreover, I wont use ADAR' s RAM to store phase and amplitude settings. I will use DDR3 external RAM to drive with my spi in FPGA part.
The ADAR1000 by default sources it gain, phase and bias data from the on-chip RAM. This includes data for the PA_BIASx pins. If you want the data sourced from Registers 0x29 - 0x2D & 0x46 - 0x4A, then you must assert Bit BIAS_RAM_BYPASS in Register 0x38.