NC in HMC833 handled differently in EVAL-brd  (as not in DS)

Document created by analog-archivist Employee on Feb 23, 2016
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Hi,

Please could you advise on the correct process for the pins marked NC on the
HMC832? There is a conflict in the data sheet which states that the pins should
be RF/DC grounded and the evaluation board schematic where the pins are handled
differently, see below.

I would normally expect the data sheet to be correct and it seems to suggest
the better engineering solution, but we should know the reason why the eval
board is wired differently and if there is an important reason for this.

This shows that;

1.    NC 11 to 14 are not connected.

2.    NC18 to 20 are connected to 3.3V.

3.    NC21 to 22 are connected to the loop filter V tune line.

4.    NC24 and 26 is connected to VCC1 to VCO analog power supply.

5.    NC33, 36 and 37 are not connected.

Which data is correct, data sheet or evaluation board?

 

 

The NC (no connect) pins have no internal bond wire connection to the die.   We
connect signals to various NC pins on our Eval-board simply to help with
routing.    For example the Vtune signal on pin 23 is routed through no connect
pins 21 and 22.  Customers can either copy the routing from the Eval-board or
just connect all NC pins to ground as recommended by the datasheet.

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