SLVU444A March 2011 – August 2021 TPS54429E
3.1 Output Voltage Setpoint
To change the output voltage of the EVMs, it is necessary to change the value of resistor R1. Changing the value of R1 can change the output voltage above 0.765 V. The value of R1 for a specific output voltage can be calculated using Equation 1 and Equation 2.
For output voltage from 0.76 V to 2.5 V:
For output voltage over 2.5 V:
Table 3-1 lists the R1 value for some common output voltages. For higher output voltages of 1.8 V or above, a feedforward capacitor (C2) may be required to improve phase margin and is recommended for auto skip Eco-mode stability. Pads for this component (C2) are provided on the printed-circuit board. Note that the values given in Table 3-1 are standard values and not the exact value calculated using Table 3-1.
| Output Voltage (V) | R1 (kΩ) | R2 (kΩ) | C2 (pF) | L1 (µH) |
|---|---|---|---|---|
| 1.0 | 6.81 | 22.1 | 1.5 | |
| 1.05 | 8.25 | 22.1 | 1.5 | |
| 1.2 | 12.7 | 22.1 | 1.5 | |
| 1.5 | 23.2 | 22.1 | 1.5 | |
| 1.8 | 30.1 | 22.1 | 10 - 22 | 2.2 |
| 2.5 | 49.9 | 22.1 | 10 - 22 | 2.2 |
| 3.3 | 73.2 | 22.1 | 10 - 22 | 2.2 |
| 5.0 | 121 | 22.1 | 10 - 22 | 3.3 |