Datasheet

Modifications
1-5
Introduction
1.3 Modifications
The SLVP213 is designed to demonstrate the small size that can be attained
when designing with the TPS54x10, so many of the features which allow for
extensive modifications have been omitted from this EVM. The output voltage
can be changed in the range of 0.9 V to 3.3 V (2.5 V for the TPS54910) by
changing the value of R4. The value of R4 for a specific output voltage can be
calculated by using the following equation. Table 1−5 lists the values of R4 for
some common output voltages.
R4 + 10 kW
0.891 V
V
O
–0.891 V
Table 1−5.Output Voltage Programming
Output Voltage (V) R4 Value (kΩ)
0.9 1000
1.2 28.7
1.5 14.7
1.8 9.76
2.5 5.49
3.3 3.74
The switching frequency can be trimmed to any value between 280 kHz and
700 kHz by changing the value of R5. Decreasing the switching frequency
results in increased output ripple unless the value of L1 is also increased. A
plot of the value of R5 versus the switching frequency is shown in Figure 1−1.
Figure 1−1. Frequency Trimming Resistor Selection
250
300
350
400
450
500
550
600
650
700
750
60 70 80 90 100 110 120 130 140 150 160 170 180
Switching Frequency − kHz
Resistance − kΩ