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A P-channel MOSFET is used as the VBUS provider control FET in CCG3PA designs (CYPD3171, CYPD3174, CYPD3175, CYPD3195, and CYPD3196 parts). Consider the following when selecting a suitable P-MOSFET:

1. Drain-source breakdown voltage (V_DS)

Make sure that the V_DS breakdown voltage is at least 10% higher than the maximum VBUS_IN voltage in the application design. For Power Delivery (PD) designs supporting a VBUS voltage up to 20V, an FET with the V_DS breakdown voltage of 25 V or more is recommended.

2. On-state drain current (I_D)

Ensure that the rated on-state drain current (I_D) is higher than the maximum VBUS current in your application. I­_D should be greater than 5 A for a PD design which supports the maximum VBUS current of 5 A.

3. Drain-source on-state resistance (R_DS(ON))

Drain-source resistance of the MOSFET must be as low as possible. R_DS(ON) of <10 mΩ at 5 V V_GS is preferable. For designs with PPS support, it is critical to have low voltage drop across the FET, and thus lowest R_DS(ON) at around 3.2V V_GS.

4. Gate plateau voltage (V_GP)

In most power MOSFET datasheets, V­_GS(th) is specified at I_D of 250µA. The gate plateau voltage (V_GP) can be used to determine the gate- source voltage at which the MOSFET is fully enhanced (i.e., turned on). V_GP for the maximum rated I_D is mentioned explicitly in the FET datasheet or can be found using a plot of V­_GS vs the Total Gate Charge. V_GP of the FET must be less than 2.8 V. This will enable the FET to be completely turned on under 3.2V V_GS.

See the following example VBUS provider FET circuit for other considerations while designing the FET circuitry:

Figure 1. VBUS Provider FET circuit

• CCG3PA drives the VBUS_P_CTRL pin to 0 V when the FET is turned ON. You should ensure that the absolute maximum rating of V_GS is more than the maximum VBUS_IN voltage. If this condition is not satisfied, a Zener diode (D11) with the Zener voltage less than the absolute maximum V_GS can be used as shown in figure to clip the gate to the source voltage within the FET rating. Diode (D11) is not required if the FET can handle V_{GS ­}greater than VBUS_IN.
• Resistor (R43) is added to limit the current through the Zener diode to a safe level.
• The ratio of R5 and R43 must be as high as possible. This will ensure a higher V_GS at relatively low values of the VBUS voltage.

Some recommended FETs:

1. IRF9358PbF by Infineon Technologies
2. DMP3036SSD by Diodes Inc.
3. DMP3010LPSQ by Diodes Inc. (Automotive qualified)
4. Si7997DP by Vishay Siliconix