QRW025A0F41-H Lineage Power, QRW025A0F41-H Datasheet - Page 22

• Manufacturer Part Number: QRW025A0F41-H
• Description: DC/DC Converters & Regulators 3.3V 25A 10-Pin
• Manufacturer: Lineage Power

Specifications of QRW025A0F41-H

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 108981267

Lineage Power
Thermal Considerations
The power modules operate in a variety of thermal environ-
ments; however, sufficient cooling should be provided to
help ensure reliable operation of the unit. Heat-dissipating
components are mounted on the top side of the module.
Heat is removed by conduction, convection and radiation to
the surrounding environment. Proper cooling can be verified
by measuring the temperature of selected components on
the topside of the power module (See 38). Peak temperature
(Tref) can occur at any of these positions indicated in Figure
50.
Note:Top view, pin locations are for reference only.
Figure 38. Temperature Measurement Location.
The temperature at any one of these locations should not
exceed per Table 1 to ensure reliable operation of the power
module. The output power of the module should not exceed
the rated power for the module as listed in the Ordering
Information table.
Although the maximum Tref temperature of the power mod-
ules is per Table 1, you can limit these temperatures to a
lower value for extremely high reliability.
Table 1.
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat trans-
fer via convection. Figures 39 through 43 shows the maxi-
mum current that can be delivered by the corresponding
module without exceeding the maximum case temperature
August 23, 2010
Output Voltage
1.2V
1.5V
1.8V
2.5V
3.3V
Device Temperature
Device
Tref1
Tref1
Tref1
Tref1
Tref1
Temperature (°C)
114
111
117
117
117
1
36 Vdc - 75 Vdc Input, 1.2 to 3.3 Vdc Output; 25A
versus local ambient temperature (TA) for natural convection
through 2 m/s (400 ft./min.).
Note that the natural convection condition was measured at
0.05 m/s to 0.1 m/s (10ft./min. to 20 ft./min.); however, sys-
tems in which these power modules may be used typically
generate natural convection airflow rates of 0.3 m/s (60 ft./
min.) due to other heat dissipating components in the sys-
tem. The use of output power derating curve is shown in the
following example.
What is the minimum airflow necessary for a QRW025A0F
operating at VI = 48 V, an output current of 25A, and a maxi-
mum ambient temperature of 70 °C.
Solution
Given: VI = 48V
Io = 25A
TA = 70 °C
Determine airflow (v) (Use Figure 43):
v = 1m/sec. (200ft./min.)
Figure 39. Output Power Derating for QRW025A0P (Vo =
Figure 40. Output Power Derating for QRW025A0M (Vo
40
35
30
25
20
15
10
40
35
30
25
20
15
10
5
0
5
0
20
20
1.2V) in Transverse Orientation with No
Baseplate; Airflow direction from VIN (+) to
VIN (–); VIN = 48V.
= 1.5V) in Transverse Orientation with No
Baseplate; Airflow direction from VIN (+) to
VIN (–); VIN = 48V.
30
LOCAL AMBIENT TEMPERATURE, T (°C)
30
LOCAL AMBIENT TEMPERATURE, T (°C)
40 50
40 50
60
60 70
70
80
A
A
80 90
90
22