The dead battery resistors of the PD controller also need to be present so the PD controller properly boots up in

dead battery operation with the correct voltages on the CC pins.

Once this process has occurred, the TPS25751 can start negotiating with the power adapter through USB PD for

higher power levels, allowing 100W operation in dead battery mode.

For more information on the TPD4S201 dead battery operation, see the CC Dead Battery Resistors Integrated

for Handling the Dead Battery Use Case in Mobile Devices section of the data sheet.

7.2.2.3 CC Line Capacitance

USB PD has a specification for the total amount of capacitance that is required for proper USB PD BMC

operation on the CC lines.

Table 7-2. USB PD cReceiver Specification

NAME

DESCRIPTION

MIN

MAX

UNIT

COMMENT

cReceiver

CC receiver capacitance

200

600

pF

The DFP or UFP system have

capacitance within this range when

not transmitting on the line

When USB PD is in use, keep the capacitance of the CC lines between 200pF and 600pF. The combination

of capacitances added to the system by the TPS25751, the TPD4S201, and any external capacitor need to fall

within these limits.

7.2.2.4 Additional ESD Protection on CC and SBU Lines

If additional IEC ESD protection is desired to be placed on either the CC or SBU lines, it is important that

high-voltage ESD protection diodes be used. The maximum DC voltage sensed on the CC or SBU lines in USB

PD SPR is 21V, with 21.5V allowed during voltage transitions. To prevent the diode from breaking down during a

short-to-VBUS event, use an ESD protection diode that has a reverse stand off voltage higher than 21.5V.

The short-to-VBUS event applies a DC voltage to the CC and SBU pins, do not use a deep-snap-back diode

unless its minimum trigger voltage is above 42V. During a short-to-VBUS event, RLC ringing of up to twice the

settling voltage is exposed to CC and SBU, allowing for up to 42V to be exposed to the CC and SBU lines.

Greater ringing can occur if any capacitor derates on the CC or SBU line. Since this ringing is hard to bound, it is

recommended to not use deep-snap-back diodes. If the deep-snap-back diode triggers during the short-to-VBUS

hot-plug event, it begins to operate in its conduction region. With a 21V VBUS source present on the CC or SBU

line, this allows the diode to conduct indefinitely.

7.2.2.5 FLT Pin Operation

Once a short-to-VBUS occurs on the C_CCx or C_SBUx pins, the FLT pin is asserted in 20µs (typical) to quickly

notify the PD controller. If VBUS is being shorted to CC or SBU, it is recommended to respond to the event by

forcing a detach in the USB PD controller to remove VBUS from the port. The TPD4S201 provides protection

from these shorting events, but does not protect the other device connected through the USB Type-C Cable

or any active circuitry in the cable. Although shutting the VBUS off through a detach does not always stop the

other device or cable from being damaged, it mitigates any high current paths from causing further damage

after the initial damage. Additionally, even if the active cable or other device does have proper protection, the

short-to-VBUS event is capable of corrupting a configuration in an active cable or in the other PD controller, so it

is best to detach and reconfigure the port.

7.2.2.6 How to Connect Unused Pins

If either the RPD_Gx pins are unused in a design, connect them to GND.

TPD4S201

SLVSIF2 – JULY 2025

www.ti.com

16

Submit Document Feedback

Copyright © 2025 Texas Instruments Incorporated

Product Folder Links: TPD4S201