DAK-71A Power Integrations, DAK-71A Datasheet - Page 20

• Manufacturer Part Number: DAK-71A
• Description: KIT DESIGN ACCELERATOR DC-DC
• Manufacturer: Power Integrations
• Series: DPA-Switch®r

Specifications of DAK-71A

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Isolated
• Voltage - Output: 3.3V
• Current - Output: 2A
• Voltage - Input: 36 ~ 72V
• Regulator Topology: Flyback
• Frequency - Switching: 400kHz
• Board Type: Bare (Unpopulated) and Fully Populated
• Utilized Ic / Part: DPA423, DPA424, DPA425
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 596-1009

EP-71 3.3 V, 2 A DC-DC Power Supply
11 Thermal Performance
The temperatures of key components were recorded using T-type thermocouples. Two
of the four thermocouples were soldered, one directly to a SOURCE pin of the DPA423G
(U1) and the other to the cathode of the output rectifier (D1). The other two
thermocouples were glued, one to the transformer (T1) core on the center leg, and the
other to the case of the first of the two high-ripple output capacitors (C7).
The unit was operated at full load, at 36 VDC, 48 VDC and 57 VDC in free convection
within a small enclosure to prevent external air currents affecting the measurements.
The results show adequate thermal margin, considering an additional ambient rise of
+29 °C. At 36 VDC, full load, within an enclosure at elevated 50 °C ambient, this equates
to a DPA423G case temperature of 79 °C. This is well below the recommended
maximum case temperature of 100 °C.
An infrared measurement taken at nominal-line (48 VDC) is provided.
Power Integrations
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Ambient
DPA423G (U1)
Transformer core (T1)
Output Rectifier (D1)
Output Capacitor (C7)
Item
Measured Temperature (
36 VDC 48 VDC 57 VDC
21
50
75
66
42
°
21
49
74
64
41
C)
21
49
74
64
42
Page 20 of 28
19-Jul-2005