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| 型号： | UQQ-3.3/25-Q48NB-C |
| 厂商： | Murata Power Solutions Inc |
| 文件页数： | 17/18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
Calculating Maximum Power Dissipation
To determine the maximum amount of internal power dissipation, ?nd the
ambient temperature inside the enclosure and the air?ow (in Linear Feet per
Minute – LFM) at the converter. Determine the expected heat dissipation using
the Ef?ciency curves and the converter Input Voltage. You should also compen-
sate for lower atmospheric pressure if your application altitude is considerably
above sea level.
The general proceedure is to compute the expected temperature rise of the
heatsink. If the heatsink exceeds +100°C. either increase the air?ow and/or
reduce the power output. Start with this equation:
Internal Heat Dissipation [Pd in Watts] = (Ts – Ta)/R ? [at air?ow] [6]
where “Ta” is the enclosure ambient air temperature and,
where “Ts” is the heatsink temperature and,
where “R ? [at air?ow]” is a speci?c heat transfer thermal resistance (in
degrees Celsius per Watt) for a particular heat sink at a set air?ow rate. We
have already estimated R ? [at air?ow] 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 R ? [at air?ow]) + Ta [7]
Heat Sink Example
Assume an ef?ciency of 92% and power output of 100 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. ?gure also allows some margin in case the ambient climbs
above +30°C or the input voltage varies, giving us less than 92% ef?ciency.
The heat sink and air?ow combination must have the following characteristics:
8.7 W = (90-30) / R ? [air?ow] or,
R ? [air?ow] = 60/8.7 = 6.9°C/W
Since the ambient thermal resistance of the heatsink and pad is 12.5°C/W, we
need additional forced cooling to get us down to 6.9°C/W. Using a hypothetical
air?ow constant of 0.005, we can rearrange equation [5] as follows:
(Required Air?ow, LFM) x (Air?ow Constant) = R ? [Nat.Convection] /
R ? [at air?ow] –1, or,
(Required Air?ow, LFM) x (Air?ow Constant) = 12.5/6.9 –1 = 0.81
and, rearranging again,
(Required Air?ow, LFM) = 0.81/0.005 = 162 LFM
162 LFM is the minumum air?ow to keep the heatsink below +90°C. Increase
the air?ow to several hundred LFM to reduce the heatsink temperature further
and improve life and reliability.
2.28
(57.91)
1.860
H eatsink Kit *
Model Number
HS-QB25-UVQ
HS-QB50-UVQ
Still Air (Natural convection)
thermal resistance
12°C/Watt
10.6°C/Watt
Heatsink height
(see drawing)
0.25" (6.35mm)
0.50" (12.7mm)
(47.24)
HS-QB100-UVQ 8°C/Watt 1.00" (25.4mm)
* Kit includes heatsink, thermal pad and mounting hardware. These are
1.03 1.45
(26.16) (36.83)
non-RoHS models. For RoHS-6 versions, add “-C” to the model number
(e.g., HS-QB25-UVQ-C).
These model numbers are correct for the UQQ series.
0.140 DIA. (3.56) (4 PLACES)
*
MATERIAL: BLACK ANODIZED ALUMINUM
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)
Dimensions in inches (mm)
Figure 8. Optional Heatsink
www.murata-ps.com/support
MDC_UQQ.D03 Page 17 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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