參數(shù)資料
型號(hào): UQQ-3.3/25-Q12P9-C
廠商: CD TECHNOLOGIES INC
元件分類: 電源模塊
英文描述: 1-OUTPUT 82.5 W DC-DC REG PWR SUPPLY MODULE
封裝: ROHS COMPLIANT PACKAGE-9
文件頁數(shù): 3/17頁
文件大?。?/td> 1988K
代理商: UQQ-3.3/25-Q12P9-C
MDC_UQQ_A03 Page of 7
UQQ Series
Wide Input Range Single Output DC/DC Converters
D C / D C C O N V E R T E R S
Technical enquiries email: sales@murata-ps.com, tel: + 508 339 3000
www.murata-ps.com
The general proceedure is to compute the expected temperature rise of the
heatsink. If the heatsink exceeds +00°C. either increase the airflow and/or
reduce the power output. Start with this equation:
Internal Heat Dissipation [Pd in Watts] = (Ts – Ta)/RQ [at airflow] [6]
where “Ta” is the enclosure ambient air temperature and,
where “Ts” is the heatsink temperature and,
where “R
Q [at airflow]” is a specific heat transfer thermal resistance (in
degrees Celsius per Watt) for a particular heat sink at a set airflow rate. We
have already estimated R
Q [at airflow] in the equations above.
Note particularly that Ta is the air temperature inside the enclosure at the
heatsink, not the outside air temperature. Most enclosures have higher
internal temperatures, especially if the converter is “downwind” from other
heat-producing circuits. Note also that this “Pd” term is only the internal heat
dissipated inside the converter and not the total power output of the converter.
We can rearrange this equation to give an estimated temperature rise of the
heatsink as follows:
Ts = (Pd x RQ [at airflow]) + Ta [7]
8.7 W = (90-30) / R
Q[airflow] or,
R
Q[airflow] = 60/8.7 = 6.9°C/W
Since the ambient thermal resistance of the heatsink and pad is 2.5°C/W, we
need additional forced cooling to get us down to 6.9°C/W. Using a hypothetical
airflow constant of 0.005, we can rearrange equation [5] as follows:
(Required Airflow, LFM) x (Airflow Constant) = R
Q[Nat.Convection] /
R
Q[at airflow] –, or,
(Required Airflow, LFM) x (Airflow Constant) = 2.5/6.9 – = 0.8
and, rearranging again,
(Required Airflow, LFM) = 0.8/0.005 = 62 LFM
62 LFM is the minumum airflow to keep the heatsink below +90°C. Increase
the airflow to several hundred LFM to reduce the heatsink temperature further
and improve life and reliability.
H
eatsink Kit *
Model Number
Still Air (Natural convection)
thermal resistance
Heatsink height
(see drawing)
HS-QB25-UVQ
2°C/Watt
0.25" (6.35mm)
HS-QB50-UVQ
0.6°C/Watt
0.50" (2.7mm)
HS-QB00-UVQ
8°C/Watt
.00" (25.4mm)
* Kit includes heatsink, thermal pad and mounting hardware.
0.10
(2.54)
*
* UQQ SERIES HEATSINKS ARE AVAILABLE IN 3 HEIGHTS:
0.25 (6.35), 0.50 (12.70) AND 1.00 (25.4)
1.45
(36.83)
2.28
(57.91)
MATERIAL: BLACK ANODIZED ALUMINUM
1.03
(26.16)
1.860
(47.24)
0.140 DIA. (3.56) (4 PLACES)
Dimensions in inches (mm)
Optional Heatsink
These model numbers are correct for the UQQ series.
Heat Sink Example
Assume an efficiency of 92% and power output of 00 Watts. Using equation
[4], Pd is about 8.7 Watts at an input voltage of 48 Volts. Using +30°C ambient
temperature inside the enclosure, we wish to limit the heat sink temperature to
+90°C maximum baseplate temperature to stay well away from thermal shut-
down. The +90°C. figure also allows some margin in case the ambient climbs
above +30°C or the input voltage varies, giving us less than 92% efficiency.
The heat sink and airflow combination must have the following characteristics:
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UQQ-5/17-Q12PB9-C 制造商:Murata Power Solutions 功能描述:
UQQ-5/17-Q12PB-C 功能描述:DC/DC轉(zhuǎn)換器 12Vin 5Vout 17A pos TH baseplate RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓(標(biāo)稱): 輸出端數(shù)量:1 輸出電壓(通道 1):3.3 V 輸出電流(通道 1):600 mA 輸出電壓(通道 2): 輸出電流(通道 2): 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
UQQ-5/17-Q12PB-C 制造商:Murata Power Solutions 功能描述:DC/DC Converter