PGA855: Thermal Pad connection

Hao Jie Chan

Part Number: PGA855

Tool/software:

Hi TI,

Can the thermal pad of PGA855 be connected to GND?

The reason is, that other ICs that I am using has another thermal pad that requires a GND connection. I am thinking of attaching a heatsink to some GND copper plane, so it would help if PGA855 could be cooled with the same GND plane.

2 months ago

+1 Marek Lis 2 months ago

TI__Guru 62700 points

Hao,

First thing first - a ground is a relative term. Thus, if you power PGA855 from a single supply, which means that a negative supply pin (V-) is connected to a system GND, then you should connect its thermal pad to GND (-V). However, if you power PGA855 from a dual supply, (V+) and (V-), then you must connect its thermal pad to a negative supply, (V-), and not GND, or leave it floating.

0 Hao Jie Chan 2 months ago in reply to Marek Lis

Prodigy 250 points

Thanks Marek.

Yes the PGA855 is powered from a dual supply, too bad its thermal pad cannot share the same GND plane as the other ICs.

0 Marek Lis 2 months ago in reply to Hao Jie Chan

TI__Guru 62700 points

If other IC’s are also powered from dual supplies, their thermal pad (if any) should also be connected to negative supply.

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PGA855: Thermal Pad connection