VREF
2nd Stage Mux Input
RP5
RP100
LDO_3V3
RP100
RP5
LDO_3V3
RP5
RP100
LDO_3V3
RP100
RP5
LDO_3V3
To Digital Core
To Digital Core
1st Stage
Mux
2nd Stage
Mux
RPD1
RPD1
51
SLVSDC2B – FEBRUARY 2016 – REVISED AUGUST 2016
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Copyright © 2016, Texas Instruments Incorporated
Figure 45. Port Detect and Pull-up and Pull-down
9.3.4.5 Port Multiplexer Clamp
Each input to the 2
nd
stage multiplexer is clamped to prevent voltages on the port from exceeding the safe
operating voltage of circuits attached to the System-side of the Port Data Multiplexer.
shows the
simplified clamping circuit. When a path through the 2
nd
stage multiplexer is closed, the clamp is connected to
the one of the port pins (C_USB_TP/N, C_USB_BP/N, C_SBU1/2). When a path through the 2
nd
stage
multiplexer is not closed, then the port pin is not clamped. As the pin voltage rises above the VCLMP_IND
voltage, the clamping circuit activates, and sinks current to ground, preventing the voltage from rising further.
Figure 46. Port Multiplexer Clamp