ADL5802 overheating

I have designed a receiver including ADL5802,

1- I followed the datasheet, set enbl value to low, connecting it to ground through a cap.
2- Setted the VSET to 3.3V taking it from voltage regulator.
3- Used recommended minicircuits baluns etc.

Aside from these the design is almost same with eval board schematics,
But at the power up, (there are no RF or LO signal) the ADL5802 starts to heat up.
I have checked the soldering, but can not see a problem.

What could be the issue?

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  • +1
    •  Analog Employees 
    on Feb 10, 2021 11:11 PM in reply to baykalyu

    From ADL5802's thermal parameters shown in the datasheet:

    Theta JA = (Tj - TA) / Pd

    Tj = (Theta JA) * Pd + TA

    Assuming ambient temp (TA) is 20degC, and power dissipation of 1.1W (5V * 220mA):

    Tj = 26.5 * 1.1 + 20 = 49.2degC

    Theta JC = (Tj - TC) / Pd

    TC= Tj - (Theta JC) * Pd

    TC = 49.2 - (8.7 * 1.1) = 39.6degC

    Note that this calculation assumes using ADI evaluation board. TC is at the IC's exposed paddle. Case top will be a little bit hotter.