dpa422 Power Integrations, Inc., dpa422 Datasheet - Page 27

• Manufacturer Part Number: dpa422
• Description: Highly Integrated Dc-dc Converter Ics For Power Over Ethernet & Telecom Applications
• Manufacturer: Power Integrations, Inc.

The following precautions should be followed when testing
DPA-Switch by itself outside of a power supply. The schematic
shown in Figure 33 is suggested for laboratory testing of
DPA-Switch.
When the DRAIN pin supply is turned on, the part will be in the
auto-restart mode. The CONTROL pin voltage will be
oscillating at a low frequency between 4.8 V and 5.8 V and the
drain is turned on every eighth cycle of the CONTROL pin
oscillation. If the CONTROL pin power supply is turned on
Typical Performance Characteristics
www.powerint.com
BENCH TEST PRECAUTIONS FOR EVALUATION OF ELECTRICAL CHARACTERISTICS
Figure 35. Current Limit vs. External Current Limit Resistance.
Figure 34. Current Limit vs. EXTERNAL CURRENT LIMIT Pin Current.
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
-230
Minimum
5
-180
External Current Limit Resistor R
10
Typical
Maximum
I
-130
15
X
(μA)
while in this auto-restart mode, there is only a 12.5% chance
that the CONTROL pin oscillation will be in the correct state
(drain active state) so that the continuous drain voltage
waveform may be observed. It is recommended that the V
power supply be turned on fi rst and the DRAIN pin power
supply second if continuous drain voltage waveforms are to be
observed. The 12.5% chance of being in the correct state is
due to the divide-by-8 counter. Temporarily shorting the
CONTROL pin to the SOURCE pin will reset DPA-Switch, which
then will come up in the correct state.
20
-80
IL
(kΩ)
25
-30
DPA422-426
30
0
35
Rev. S 12/07
C
27