TDC1000: VCOM Resistor Divider Values

Antonio Fadhel

Part Number: TDC1000

Team,

My customer noticed that we use very high resistance values for the VCOM pin resistor divider, and they were wondering if there is a reason for that. Do they need to be in the several-MOhm range? The only reason I can think of is to avoid overloading the pin if the VCOM_SEL bit is set to internal.

Also, could they drive the pin with an op-amp or voltage reference instead?

Thanks,
Antonio

over 6 years ago

0 Bharat Aravamudhan over 6 years ago

TI__Genius 11015 points

Antonio,

I will check on any information regarding this VCOM pin resistor divider and get back with you soon.

0 Bharat Aravamudhan over 6 years ago in reply to Bharat Aravamudhan

TI__Genius 11015 points

Antonio,

The output of the internal common-mode buffer is present at the VCOM pin. This pin should be bypassed to ground with a low-leakage 10-nF capacitor and it should not be loaded with more than 20 µA. The common mode buffer can be disabled with the VCOM_SEL bit in the CONFIG_2 register. If disabled, an external reference voltage must be applied to the VCOM pin.

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TDC1000: VCOM Resistor Divider Values