SLVSH61D March 2025 – September 2026 TPS7H4102-SEP , TPS7H4104-SEP , TPS7H4104-SP
PRODUCTION DATA
The soft-start capacitor CSS_TRx, determines the amount of time for the output voltage to reach nominal programmed value during power up. This is useful if a load requires a controlled voltage slew rate. This is also used if the output capacitance is large (as is typical with space grade buck converters), which requires a large amount of current to quickly charge the capacitor to the output voltage level. The large currents necessary to charge the capacitor can make the TPS7H410x reach the current limit, draw excessive current from the input power supply, or cause the input voltage rail to sag. Limiting the output voltage slew rate solves these problems. Calculate the soft-start capacitor value using Equation 19 and Equation 20. Table 9-7 shows the calculated value, along with the selected values. The center across temperature and voltage is used for VREFx and ISS_TRx for the calculations as: Equation 21, Equation 21, respectively.
| VOUTx (V) | tSS_TRx_NOMINAL (ms) | CSS_TRx_NOMINAL (nF) | CSS_TRx_SELECTED (nF) |
|---|---|---|---|
| 0.8 | 0.31 | 1.11 | 1.2 |
| 1.2 | 0.47 | 1.66 | 1.8 |
| 1.5 | 0.59 | 2.08 | 2.2 |
| 1.8 | 0.71 | 2.5 | 2.7 |