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ADL5513 with Vdd=3.3V and Tadj

Hi all,

We will like to use the ADL5513 logarithmic detector with a 3.3V supply voltage, in the frequency range between 2.6 and 3GHz.

According to Figure 21 of the datasheet, it seems to behave the same with variations on the power supply voltage, at least in 1900MHz.

In Figure 10 of the datasheet, the measurement conditions are Vdd=5V and Vtadj=0.83V. To my understanding of the text under the tittle "Device calibration", this value of Vtadj is optimized for 85°C, is this correct?

To optimize operation at 25°C, the pin Vtadj should be let open? (we are not using the disable feature).

Is Vtadj dependant of the supply voltage?

Best Regards,

Santiago Calvo

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  • Greetings Santiago,

    Figure 21 caption is wrong. It reads 1900 MHz, it should be 100 MHz. We are working to correct this known datasheet error ASAP. 

    The Table 4 VTADJ recommendations are for best (lowest) temperature drift, after room temperature calibration. This includes both hot and cold excursions. For 2.6GHz operation, the recommended voltage is 0.83V as stated. If VTADJ pin is left open, it floats to approx. 0.9V, so error is not too bad if the pin is left open. Note, the calibration should be performed AFTER VTADJ is set as desired, not before. 

    I'm not aware of any VTADJ dependencies on VPOS supply voltage.   -Bruce H. 

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  • Greetings Santiago,

    Figure 21 caption is wrong. It reads 1900 MHz, it should be 100 MHz. We are working to correct this known datasheet error ASAP. 

    The Table 4 VTADJ recommendations are for best (lowest) temperature drift, after room temperature calibration. This includes both hot and cold excursions. For 2.6GHz operation, the recommended voltage is 0.83V as stated. If VTADJ pin is left open, it floats to approx. 0.9V, so error is not too bad if the pin is left open. Note, the calibration should be performed AFTER VTADJ is set as desired, not before. 

    I'm not aware of any VTADJ dependencies on VPOS supply voltage.   -Bruce H. 

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