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LM1117MPX-5.0 参数 Datasheet PDF下载

LM1117MPX-5.0图片预览
型号: LM1117MPX-5.0
PDF下载: 下载PDF文件 查看货源
内容描述: 800毫安低压差线性稳压器 [800mA Low-Dropout Linear Regulator]
分类和应用: 线性稳压器IC调节器电源电路光电二极管输出元件
文件页数/大小: 30 页 / 2507 K
品牌: TI [ TEXAS INSTRUMENTS ]
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LM1117-N  
www.ti.com  
SNOS412L MAY 2004REVISED JULY 2012  
PD = (VIN-VOUT)I L + VINIG  
Figure 13 shows the voltages and currents which are present in the circuit.  
Figure 13. Power Dissipation Diagram  
The next parameter which must be calculated is the maximum allowable temperature rise, TR(max):  
TR(max) = TJ(max)-TA(max)  
where TJ(max) is the maximum allowable junction temperature (125°C), and TA(max) is the maximum ambient  
temperature which will be encountered in the application.  
Using the calculated values for TR(max) and PD, the maximum allowable value for the junction-to-ambient  
thermal resistance (θJA) can be calculated:  
θJA = TR(max)/PD  
If the maximum allowable value for θJA is found to be 136°C/W for SOT-223 package or 79°C/W for TO-220  
package or 92°C/W for TO-252 package, no heatsink is needed since the package alone will dissipate enough  
heat to satisfy these requirements. If the calculated value for θJA falls below these limits, a heatsink is required.  
As a design aid, Table 1 shows the value of the θJA of SOT-223 and TO-252 for different heatsink area. The  
copper patterns that we used to measure these θJAs are shown at the end of APPLICATION INFORMATION.  
Figure 14 and Figure 15 reflects the same test results as what are in the Table 1  
Figure 16 and Figure 17 shows the maximum allowable power dissipation vs. ambient temperature for the SOT-  
223 and TO-252 device. Figure 18 and Figure 19 shows the maximum allowable power dissipation vs. copper  
area (in2) for the SOT-223 and TO-252 devices. Please see AN1028 for power enhancement techniques to be  
used with SOT-223 and TO-252 packages.  
Application Note AN-1187 discusses improved thermal performance and power dissipation for the LLP.  
Table 1. θJA Different Heatsink Area  
Layout  
Copper Area  
Thermal Resistance  
Top Side (in2)(1)  
Bottom Side (in2)  
(θJA,°C/W) SOT-223  
(θJA,°C/W) TO-252  
1
2
0.0123  
0.066  
0.3  
0
0
136  
123  
84  
103  
87  
60  
54  
52  
47  
84  
70  
63  
57  
57  
89  
72  
61  
3
0
4
0.53  
0.76  
1
0
75  
5
0
69  
6
0
66  
7
0
0.2  
0.4  
0.6  
0.8  
1
115  
98  
8
0
9
0
89  
10  
11  
12  
13  
14  
0
82  
0
79  
0.066  
0.175  
0.284  
0.066  
0.175  
0.284  
125  
93  
83  
(1) Tab of device attached to topside copper  
Copyright © 2004–2012, Texas Instruments Incorporated  
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13  
Product Folder Links: LM1117-N