SLVU953A October 2013 – May 2021 TPS65580 , TPS65581
3.1 Output Voltage Setpoint
To change the output voltage of the EVMs, it is necessary to change the value of the top resistor in the voltage set point divider network (R9, R13, and R17). Changing the value of RTOP can change the output voltage above 0.765 V. The value of RTOP for a specific output voltage can be calculated using Equation 1.
Table 3-1 lists the RTOP values for some common output voltages. For higher output voltages of 1.8 V or above, a feed-forward capacitor (CFF) may be required to improve phase margin. Pads for this component (C12, C18, and C24 ) 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 Equation 1.
| Output Voltage (V) | RTOP (kΩ) | RBOT (kΩ) | CFF (pF) | LOUT (µH) | COUT (µF) | ||
|---|---|---|---|---|---|---|---|
| Min | Typ | Max | |||||
| 1.0 | .681 | 2.21 | 220 - 680 | 1.5 | 2.2 | 3.3 | 22 - 68 |
| 1.05 | .825 | 2.21 | 100 - 680 | 1.5 | 2.2 | 3.3 | 22 - 68 |
| 1.2 | 1.27 | 2.21 | 68 - 680 | 1.5 | 2.2 | 3.3 | 22 - 68 |
| 1.5 | 2.10 | 2.21 | 68 - 330 | 1.5 | 2.2 | 3.3 | 22 - 68 |
| 1.8 | 3.01 | 2.21 | 5 - 68 | 1.5 | 2.2 | 3.3 | 22 - 68 |
| 2.5 | 4.99 | 2.21 | 5 - 22 | 2.2 | 3.3 | 4.7 | 22 - 68 |
| 3.3 | 7.32 | 2.21 | 5 - 22 | 2.2 | 3.3 | 4.7 | 22 - 68 |
| 5.0 | 12.4 | 2.21 | 5 - 22 | 2.2 | 3.3 | 4.7 | 22 - 68 |
| 6.5 | 16.5 | 2.21 | 5 - 22 | 2.2 | 3.3 | 4.7 | 22 - 68 |