TS3V340: S2 voltage when D connect to S1

Patrick Chen(TPE System & Application)

Expert 3430 points

Part Number: TS3V340

Hi Sir,

When we set D(0V) connect to S1 and S2 is floating, we could measure a 0.3C~1V on S2 pin.

Could you help to explain why S2 is not 0V?

Many thanks,

Patrick

over 4 years ago

0 Ambroise Suter over 4 years ago

TI__Expert 3820 points

Hi Patrick,

As shown in this App Note floating pins can have all sorts of implications.
What is the VCC level and are all other signals disconnected? If not, what are their signal levels and frequencies?

Thank you and best regards,

Ambroise

0 Patrick Chen(TPE System & Application) over 4 years ago in reply to Ambroise Suter

TI__Expert 3430 points

Hi Ambroise,

D: LVDS signal.

S1: DC level = 0V with external DC cap blocking.

S2: floating.

Many thanks,

Patrick

0 Ambroise Suter over 4 years ago in reply to Patrick Chen(TPE System & Application)

TI__Expert 3820 points

Hi Patrick,

depending on the frequency and voltage level the LVDS signal is running at, it could contribute up to 0.26V (500MHz, 3.3V) due to off-isolation (Figure 3 in the Datasheet).
Other sources could come from parasitics within the CMOS switch.

Best regards,

Ambroise

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TS3V340: S2 voltage when D connect to S1