Datasheet

Modifications
1-3
Introduction
1.3 Modifications
The TPS54610 EVM is designed to support numerous types of input
capacitors, output capacitors, and inductors (see Top-Side Layout Figure 3–1,
and EVM schematic Figure 4–1). C3 provides pads for a surface mount input
capacitor, while the holes of C1 can be used for through-hole input capacitors.
Similarly, C10 and C11 provide pads for surface-mount output capacitors,
while the holes of C12 can be used for through-hole output capacitors. The
pads of L1, which are intentionally large, can accommodate a variety of power
inductors. When changing the output filter, the compensation values must also
be changed to ensure stability. The SWIFTt Designer software tool or Texas
Instruments Application Note SLVA104 – Designing With Externally
Compensated SWIFTt Regulators can be used to assist in the calculation of
compensation components. Both SWIFTt Designer software and application
note SLVA104 are available for download at the Texas Instruments web site.
The TPS54610 EVM can be easily configured to switch at either 350 kHz or
550 kHz by changing the location of jumper JP1. Alternatively, by using RT
(R3), the switching frequency can be trimmed to any value between 280 kHz
and 700 kHz. A plot of the value of RT versus the switching frequency is given
in Figure 1–1.
The output voltage of the TPS54610 EVM can be adjusted to any value down
to 0.9 V by changing only one component value (R2). The value of R2 for a
specific output voltage can be calculated by using Equation 1–1. Table 1–2
lists the value of R2 for some common bus voltages.
Equation 1–1.
R
2
+ 10 kW
0.891 V
V
O
* 0.891 V
Changing the value of C2 can modify the slow start time of the TPS54610
EVM. Use Equation 1–2 to calculate the value of C2 for a specific slow start
time. With C2 left open, the slow start time is typically 3.6 ms. The slow start
time can not be made faster than 3.6 ms.
Equation 1–2.
C
2
+
T
SS
5 mA
0.891 V