DS_DNK12SIP_09062016

12

THERMAL CONSIDERATIONS

Thermal management is an important part of the system

design. To ensure proper, reliable operation, sufficient

cooling of the power module is needed over the entire

temperature range of the module. Convection cooling is

usually the dominant mode of heat transfer.

Hence, the choice of equipment to characterize the

thermal performance of the power module is a wind

tunnel.

Thermal Testing Setup

Delta’s DC/DC power modules are characterized in

heated vertical wind tunnels that simulate the thermal

environments

encountered

in

most

electronics

equipment. This type of equipment commonly uses

vertically mounted circuit cards in cabinet racks in which

the power modules are mounted.

The

following

figure

shows

the

wind

tunnel

characterization setup. The power module is mounted on

a test PWB and is vertically positioned within the wind

tunnel. The height of this fan duct is constantly kept at

25.4mm (1’’).

Thermal Derating

Heat can be removed by increasing airflow over the

module. To enhance system reliability, the power

module should always be operated below the maximum

operating temperature. If the temperature exceeds the

maximum module temperature, reliability of the unit may

be affected.

AIR F LOW

MODULE

PWB

AIR VELOCITY

AND AMBIENT

TEMPERATURE

SURED BELOW

THE MODULE

FANCING PWB

Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)

Figure 42: Wind tunnel test setup

THERMAL CURVES

HOT SPOT

NTC RESISTOR

AIRFLOW

Figure 43: * Hot spot& NTC resistor temperature measured

points. The allowed maximum hot spot temperature is defined at

120℃.

DNK12S0A0R30(standard) Output Current vs. Ambient Temperature and Air Velocity

@Vin=12V Vout=0.8V (Through PCB Orientation)

0

5

10

15

20

25

30

25

30

35

40

45

50

55

60

65

70

75

80

85

Natural

Convection

Output Current (A)

Ambient Temperature (℃)

100LFM

200LFM

400LFM

300LFM

500LFM

600LFM

Figure 44: Output current vs. ambient temperature and air

velocity @ Vin=12V, Vout=0.8V (Through PCB Orientation,

Airflow from Pin1 to Pin13)

DNK12S0A0R30(standard) Output Current vs. Ambient Temperature and Air Velocity

@Vin=12V Vout=1.8V (Through PCB Orientation)

0

5

10

15

20

25

30

25

30

35

40

45

50

55

60

65

70

75

80

85

Natural

Convection

Output Current (A)

Ambient Temperature (? )

100LFM

200LFM

400LFM

300LFM

500LFM

600LFM

Figure 45: Output current vs. ambient temperature and air

velocity @ Vin=12V, Vout=1.8V (Through PCB Orientation,

Airflow from Pin1 to Pin13)