7.7 U2/U3 Mode

Next to the disconnect mode, the U2/U3 mode is next lowest power state. While in this mode, the TUSB1002 periodically performs far-end receiver detection. Anytime the far-end receiver termination is not detected on either CH1 or CH2, the TUSB1002 leaves the U2/U3 mode and transition to the Disconnect mode. It also monitors the SSRX1 and SSRX2 for a valid LFPS. Upon detection of a valid LFPS, the TUSB1002 immediately transitions to the U0 mode.

When SLP_S0# is asserted low and the TUSB1002 is in U2/U3 mode, the TUSB1002 remains in U2/U3 state and never perform far-end receiver detection. While in this state, the TUSB1002 ignores LFPS signaling. This allows even lower TUSB1002 power consumption while in the U2/U3 mode. Once SLP_S0# is asserted high, the TUSB1002 again starts performing far-end receive as well as monitor LFPS so it can know when to exit the U2/U3 mode.