ZHCSLP7C December 2019 – February 2021 TPD4S311 , TPD4S311A
PRODUCTION DATA
USB PD has a specification for the total amount of capacitance that is required for proper USB PD BMC operation on the CC lines. The specification from section 5.8.6 of the USB PD Specification is given below in Table 9-3.
| NAME | DESCRIPTION | MIN | MAX | UNIT | COMMENT |
|---|---|---|---|---|---|
| cReceiver | CC receiver capacitance | 200 | 600 | pF | The DFP or UFP system shall have capacitance within this range when not transmitting on the line |
Therefore, the capacitance on the CC lines must stay in between 200 pF and 600 pF when USB PD is being used. Therefore, the combination of capacitances added to the system by the TPS65982, the TPD4S311, and any external capacitor must fall within these limits. Table 9-4 shows the analysis involved in choosing the correct external CC capacitor for this system, and shows that an external CC capacitor is required.
| CC CAPACITANCE | MIN | MAX | UNIT | COMMENT |
|---|---|---|---|---|
| CC line target capacitance | 200 | 600 | pF | From the USB PD Specification section |
| TPS65982 capacitance | 70 | 120 | pF | From the TPS65982 data sheet |
| TPD4S311 capacitance | 45 | 120 | pF | From the Electrical Characteristics table |
| Proposed capacitor GRM033R71E221KA01D | 110 | 330 | pF | CAP, CERM, 220 pF, 25 V, ±10%, X7R, 0201 (for min and max, assume ±50% capacitance change with temperature and voltage derating to be overly conservative) |
| TPS65982 + TPD4S311 + GRM033R71E221KA01D | 225 | 570 | pF | Meets USB PD cReceiver specification |