SLVS979C October 2009 – May 2018 TPS65720 , TPS65721
PRODUCTION DATA.
For TPS65720 and TPS65721, the output voltage of the DCDC converter can be set with external resistor network on Pin FB_DCDC1. The feedback voltage is 0.6 V.
TI recommends setting the total resistance of R1 + R2 to less than 1 MΩ. Route the FB_DCDC1 trace separate from noise sources, such as the inductor trace (L1).
VFB-DCDC1 = 0.6 V
OUTPUT VOLTAGE | R1 | R2 | NOMINAL VOLTAGE |
---|---|---|---|
3.3 V | 680 kΩ | 150 kΩ | 3.32 V |
3 V | 510 kΩ | 130 kΩ | 2.95 V |
2.85 V | 560 kΩ | 150 kΩ | 2.84 V |
2.5 V | 510 kΩ | 160 kΩ | 2.51 V |
2.05 V | 360 kΩ | 150 kΩ | 2.04 V |
2 V | 470 kΩ | 200 kΩ | 2.01 V |
1.8 V | 300 kΩ | 150 kΩ | 1.8 V |
1.6 V | 200 kΩ | 120 kΩ | 1.6 V |
1.5 V | 300 kΩ | 200 kΩ | 1.5 V |
1.2 V | 330 kΩ | 330 kΩ | 1.2 V |
A feedforward capacitor in parallel to the resistor from Vout to FB_DCDC1 is required. Its value should be based on transient performance and will be in the range from 4.7 pF to 22 pF.
For TPS657201, the output voltage of DCDC1 is fixed at 1.85 V per default and can be changed in register DEFDCDC1. For TPS657202, the default output voltage is 1.9 V. The feedback connection has to be made from pin FB_DCDC1 to the output capacitor directly. A voltage change to a higher voltage needs to be accomplished in steps of 8% maximum otherwise the power-good comparator will detect a too low voltage, will trigger and generate a reset. There is no limitation in programming output voltages to lower values.