Datasheet

Loop Characterization Setup
2-3
Test Setup and Results
2.2 Loop Characterization Setup
The TPS54610 EVM contains a 49.9- resistor (R6) in the feedback path for
use in measuring the loop response. Test points on either side of R6 (TP4 and
TP3) provide connection points for network analyzer signals. By injecting a
small AC signal across R6, the loop gain and phase can be measured from one
side of R6 to the other. Because the value of R6 is small in relation to the value
of R4, it does not affect the output voltage set point of the regulator.
2.3 Efficiency
The TPS54610 EVM efficiency peaks at around 1.5 A of load current. At full
load this drops to around 89%. Figure 22 shows the typical efficiency for a 5-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 slightly higher at 350 kHz than
at 550 kHz due to the gate and switching losses in the MOSFETs. The total
board losses are shown in Figure 23.
Figure 22. Measured Efficiency
80
85
90
95
100
0123456
F
SW
= 350 kHz
F
SW
= 550 kHz
T
A
= 25°C
I
L
Load Current A
Efficiency %