Performance Curves
Quarter
Brick
25
48Vin 3.3Vout 25A
20
I
out
(A)
15
10
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
5
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
0 LFM (0 m/s)
0
0
25
40
55
70
85
Ambient Air Temperature (
o
C)
Semiconductor junction temperature is
within 1°C of surface temperature
Figure 7:
Maximum output power-derating curves vs. ambient air tem-
perature for airflow rates of 0 LFM through 400 LFM with air flowing
lengthwise from input to output (nominal input voltage).
Figure 8:
Thermal plot of converter at 23 amp load current with 55
°
C
air flowing at the rate of 200 LFM. Air is flowing across the converter
from input to output (nominal input voltage).
Figure 9:
Turn-on transient at full load (resistive load) (2 ms/div).
Ch 1: Vout (1V/div)
Ch 2: ON/OFF input (5V/div)
Figure 10:
Turn-on transient at zero load (2 ms/div).
Ch 1: Vout (1V/div)
Ch 2: ON/OFF input (5V/div)
Figure 11
:
Output voltage response to step-change in load current (50%-75%-50%
of Iout(max); dI/dt = 0.1A/µs). Load cap: 10µF, 100 m
Ω
ESR tantalum capacitor
and 1µF ceramic capacitor. Ch 1: Vout (100mV/div), Ch 2: Iout (5A/div).
Product # PQ60033QGA25
Phone 1-888-567-9596
Figure 12
:
Output voltage response to step-change in load current (50%-75%-
50% of Iout(max): dI/dt = 5A/µs). Load cap: 470µF, 30 m
Ω
ESR tantalum
capacitor and 1µF ceramic cap. Ch 1: Vout (100mV/div), Ch 2: Iout (5A/div).
Doc.# 005-2QG633D Rev. B
6/26/02
Page 6
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