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John Lewis
Visitor
October 26, 2026
Question

TCPP03-M20: Recommended termination for unused consumer gate driver pins (GDCg / GDCs)

Hi,

I am designing a self-powered USB Type-C application using the TCPP03-M20 with an STM32 UCPD controller. The product supports dual-role data (DRD) and can operate as either a host or a device:

  • Host mode: Acts as a power provider (using the provider path with external N-MOSFETs driven by GDPg/GDPs).

  • Device mode: Self-powered; only requires a USB data connection and does not sink power from V_{BUS}.

Because the consumer power path is not needed, we are omitting the external consumer back-to-back MOSFETs.

Could you please clarify:

  1. Pin termination: What is the recommended hardware connection for the unused GDCg (pin 7) and GDCs (pin 8) pins? Should they be left floating (NC), tied to GND, shorted together, or pulled down with resistors?

  2. Firmware / I2C handling: Beyond keeping the consumer gate driver open via the I2C register (GDC = 1), are there any internal bias, dead-battery handling, or fault/flag behaviors on FLGn we should account for when the sink path is omitted?

Thank you!

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