TMUX8212: Sharing GND

Francis Jiang

Part Number: TMUX8212
Other Parts Discussed in Thread: ISO7740

Hi Team,

if S pin and D pin is isolated with the power pin and SEL pin, whether this device can work? In this situation, power pin and SEL pin sharing the same GND.

BRs,

Francis

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 273800 points

What exactly do you mean with "isolated"?

The S and D voltages must be between V_SS and V_DD.

0 Kameron Hill over 1 year ago

TI__Genius 14470 points

Hello Francis,

From my understanding this might be the information you are looking for.

This device will not pass a signal on a unselected channel ex(S1 to D1) What controls the path be connected or disconnected is the control logic pins(sel1-sel4) and the power pin isnt involved in channel selection. Also ther is a ground pin on this device which ever grounds the whole device.

Thanks and Regards,

Kameron

0 Francis Jiang over 1 year ago in reply to Kameron Hill

TI__Intellectual 1750 points

Hi Clemens, Kameron,

Sorry for the confusion, customer uses TMUX8212 in a isolated situation means the S/D/VDD/VSS/GND pins have a common power ground, but the logic control signal SEL pin belongs to a digital ground(isolated from power ground). Currently, they add a ISO7740 for meeting this requirement, due to we think SEL pin must have a common ground with VDD/VSS. Could you please help me check whether it is right? And if customer don't want the ISO7740, what can they do to meet the necessary requirement - power side electrical isolation? Thanks a lot.

BRs,

Francis

+1 Clemens Ladisch over 1 year ago in reply to Francis Jiang

Guru 273800 points

The SEL voltage must be referenced to GND; see the V_SEL specification in section 7.3.

In this application, you indeed need an isolator for the SEL signals.

0 Francis Jiang over 1 year ago in reply to Clemens Ladisch

TI__Intellectual 1750 points

Hi Clemens,

Got it. Thanks. No problem here.

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TMUX8212: Sharing GND