Datasheet

Input/Output Connections
2-2
2.1 Input/Output Connections
The TPS54314EVM has the following four input/output connections: J1 (V
I
and GND) and J2 (V
O
and GND). A diagram showing the connection points
is shown in Figure 2–1. Connect a power supply capable of supplying 3 A to
J1 through a pair of 20 AWG wires. Connect the load to J2 through a pair of
20 AWG wires. Minimize wire lengths to reduce losses in the wires. Test point
TP8 provides easy connection for an oscilloscope voltage probe to monitor the
output voltage.
Figure 2–1. Connection Diagram
2.2 Efficiency
The TPS54314EVM efficiency peaks at around 1 A of load current, with a 5-V
input source. At full load this drops to around 85%. Figure 2–2 shows the
typical efficiency for both a 5-V input and a 3.3-V input and an ambient
temperature of 25°C. The efficiency is lower at higher ambient temperatures,
due to temperature variation in the drain-to-source resistance of the
MOSFETs. The efficiency is also slightly higher at lower switching frequencies
due to the gate and switching losses in the MOSFETs. The efficiency is slightly
higher with a 5-V input because the higher input voltage provides more drive
voltage for the power MOSFETs, which leads to a lower drain-to-source
resistance. The total board losses are shown in Figure 2–3.