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| 型号： | UQQ-3.3/25-Q48NB-C |
| 厂商： | Murata Power Solutions Inc |
| 文件页数： | 16/18页 |
| 文件大小： | 0K |
| 描述： | CONV DC/DC 82.5W 25A 3.3V T/H |
| 标准包装： | 30 |
| 系列： | UQQ |
| 类型： | 隔离 |
| 输出数： | 1 |
| 电压 - 输入（最小）： | 18V |
| 电压 - 输入（最大）： | 75V |
| Voltage - Output 1： | 3.3V |
| 电流 - 输出（最大）： | 25A |
| 电源（瓦） - 制造商系列： | 82W |
| 电压 - 隔离： | 2.25kV（2250V） |
| 安装类型： | 通孔 |
| 封装/外壳： | 8-DIP 模块，1/4 砖 |
| 尺寸/尺寸： | 2.22" L x 1.45" W x 0.50" H（56.4mm x 36.8mm x 12.7mm） |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 85°C |
| 效率： | 88% |
| 电源（瓦特）- 最大： | 82.5W |
| 其它名称： | 811-1891-5 |
UQQ Series
Wide Input Range Single Output DC-DC Converters
UQQ Series Aluminum Heatsink
Please note – The UQQ series shares the same heatsink kits as the UVQ
series. Therefore, when ordering these heat sinks, use the model numbers
below which end with the ‘UVQ’ suf?x. The UQQ series converter baseplate
can be attached either to an enclosure wall or a heatsink to remove heat from
internal power dissipation. The discussion below concerns only the heatsink
alternative. The UQQ’s are available with a low-pro?le extruded aluminum
heatsink kit, models HS-QB25-UVQ, HS-QB50-UVQ, and HS-QB100-UVQ.
This kit includes the heatsink, thermal mounting pad, screws and mounting
hardware. See the assembly diagram below. Do not overtighten the screws in
the tapped holes in the converter. This kit adds excellent thermal performance
without sacri?cing too much component height. See the Mechanical Outline
Drawings for assembled dimensions. If the thermal pad is ?rmly attached, no
thermal compound (“thermal grease”) is required.
When assembling these kits onto the converter, include ALL kit hardware to
assure adequate mechanical capture and proper clearances. Thread relief is
0.090" (2.3mm).
Figure 7. Model UQQ Heatsink Assembly Diagram
Thermal Performance
The HS-QB25-UVQ heatsink has a thermal resistance of 12 degrees Celsius
per Watt of internal heat dissipation with “natural convection” air?ow (no
fans or other mechanical air?ow) at sea level altitude. This thermal resistance
assumes that the heatsink is ?rmly attached using the supplied thermal pad
and that there is no nearby wall or enclosure surface to inhibit the air?ow. The
thermal pad adds a negligible series resistance of approximately 0.5°C/Watt so
that the total assembled resistance is 12.5°C/Watt.
Be aware that we need to handle only the internal heat dissipation, not the full
power output of the converter. This internal heat dissipation is related to the
ef?ciency as follows:
Power Dissipation [Pd] = Power In – Power Out [1]
Power Out / Power In = Ef?ciency [in %] / 100 [2]
Power Dissipation [Pd] = Power In x (1 –Ef?ciency%/100) [3]
Power Dissipation [Pd] = Power Out x (1 / (Ef?ciency%/100) - 1) [4]
Ef?ciency of course varies with input voltage and the total output power. Please
refer to the Performance Curves.
Since many applications do include fans, here is an approximate equation to
calculate the net thermal resistance:
R ? [at air?ow] = R ? [natural convection] / (1 + (Air?ow in LFM) x
[Air?ow Constant]) [5]
Where,
R ? [at air?ow] is the net thermal resistance (in °C/W) with the amount of
air?ow available and,
R ? [natural convection] is the still air total path thermal resistance or in this
case 12.5°C/Watt and,
“Air?ow in LFM” is the net air movement ?ow rate immediately at the converter.
This equation simpli?es an otherwise complex aerodynamic model but is a
useful starting point. The “Air?ow Constant” is dependent on the fan and enclo-
sure geometry. For example, if 200 LFM of air?ow reduces the effective natural
convection thermal resistance by one half, the air?ow constant would be
0.005. There is no practical way to publish a “one size ?ts all” air?ow constant
because of variations in air?ow direction, heatsink orientation, adjacent walls,
enclosure geometry, etc. Each application must be determined empirically and
the equation is primarily a way to help understand the cooling arithmetic.
This equation basically says that small amounts of forced air?ow are quite
effective removing the heat. But very high air?ows give diminishing returns.
Conversely, no forced air?ow causes considerable heat buildup. At zero air?ow,
cooling occurs only because of natural convection over the heatsink. Natural
convection is often well below 50 LFM, not much of a breeze.
While these equations are useful as a conceptual aid, most users ?nd it very
dif?cult to measure actual air?ow rates at the converter. Even if you know
the velocity speci?cations of the fan, this does not usually relate directly to
the enclosure geometry. Be sure to use a considerable safety margin doing
thermal analysis. If in doubt, measure the actual heat sink temperature with
a calibrated thermocouple, RTD or thermistor. Safe operation should keep the
heat sink below 100°C.
www.murata-ps.com/support
MDC_UQQ.D03 Page 16 of 18
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相关代理商/技术参数 |
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| UQQ-5/17-Q12NB-C | 功能描述:DC/DC转换器 12Vin 5Vout 17A neg TH baseplate RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| UQQ-5/17-Q12N-C | 功能描述:DC/DC转换器 12Vin 5Vout 17A neg polarity TH RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| 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转换器 12Vin 5Vout 17A pos TH baseplate RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| UQQ-5/17-Q12PB-C | 制造商:Murata Power Solutions 功能描述:DC/DC Converter |
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