Figure 13: Test set-up diagram showing measurement points for Input

Terminal Ripple Current (Figure 14), Input Reflected Ripple Current

(Figure 15) and Output Voltage Ripple (Figure 16).

Product # PQ60033HTA50

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Doc.# 005-2HT633F Rev. A

4/11/03

Page 7

Figure 14: Input Terminal Ripple Current, ic, at full rated output cur-

electrolytic capacitor (100 mA/div). (See Figure 13)

inductor at nominal input voltage and rated load current (5 mA/div).

(See Figure 13)

Figure 16: Output voltage ripple at nominal input voltage and rated

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

35 V

48 V

75 V

Figure 17: Output voltage vs. load current showing typical current limit

curves and converter shutdown points.

Figure 18: Load current (20A/div) as a function of time when the con-

verter attempts to turn on into a 1 m

Ω short circuit. Top trace

(2ms/div) is an expansion of the on-time portion of the bottom trace.

Half

Half

Brick

Brick

Performance Curves

48Vin 3.3Vout 50A

source

impedance

DC/DC

Converter

Figure 15

Figure 14

Figure 16

ceramic

capacitor

15 µF,

450m

Ω ESR

tantalum

capacitor

47 µF,

<1

Ω ESR

electrolytic

capacitor

i

S

i

C