Datasheet

4. Activate the PSE power supply or turn on the external DC power supply.
5. Using a voltmeter, verify that MAXREFDES31# provides +3.3V across the +3.3V and GND connections
at OUT1. GND is galvanically isolated from the EV kit's input VDD and WAD pads.
6. Repeat steps 2 and 3, connecting the voltmeter to the +5V and GND terminals of OUT2 to verify that
MAXREFDES31# provides +5V across the connections at OUT2.
Lab Measurements
Equipment used:
Multimeter (Fluke 189 or equivalent)
MAX5971AEVKIT (power source equipment KGU Unit)
Oscilloscope (Tektronix TDS3034B or equivalent)
Current probe (Tektronix TCP202 or equivalent)
Voltage probe (Tektronix Tek6193A or equivalent)
Two each BK Precision 8540 electronic load or equivalent
One each 8-Port 1Gbps workgroup Ethernet switch (Netgear GS608 or equivalent)
Two each PCs with Windows XP and a 1Gbps full-duplex Ethernet network interface card (NIC).
Take special care and use proper equipment when testing the Pasadena design. Any high-power design
involves risk and the necessary safety precautions must be taken. Duplication of the presented test data
requires a low-distortion signal source.
Efficiency and Regulation
Figure 2 shows the efficiency of the DC-DC circuit, after the diode bridges, with varying output power, for
three different input voltages of 40V, 48V, and 57V. Table 2 shows the efficiency of each rail at full current,
while the other rail is at 0A. Table 3 shows line regulation, each data point is the difference of the output
voltages while the input voltage
is swept from 40V to 57V. Table 4 shows the load regulation, each data point
is the difference in output voltage from 0A to max current. Points are shown for the other rail at both 0A and
max current. Table 5 shows cross regulation, each data point is the difference in output voltage represented
by the equation below.
Cross regulation = V (3.3V = 0A, 5V = 3A) – V (3.3V = 1.8A, 5V = 0A)
Figures 3–14 show transient response of 3.3V and 5V outputs when stepped from 100% to 50% to 100%.
Figures are shown for input voltages of 40V, 48V, and 57V, and secondary rail outputs of 0A and maximum
current.
Figure 2. DC-DC efficiency of the Pasadena design, following the diode bridges.
Table 2. DC-DC Efficiency
Input voltage
DC-DC Efficiency
(3.3V = 1.8A, 5V = 0A)
DC-DC Efficiency
(3.3V = 0A, 5V = 3A)
DC-DC Efficiency
(3.3V = 1.8A, 5V = 3A)
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OUT OUT