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參數(shù)資料
| 型號： | LM2937-25 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | 400mA and 500mA Voltage Regulators |
| 中文描述： | 400mA和500mA的穩(wěn)壓器 |
| 文件頁數(shù)： | 7/11頁 |
| 文件大?。?/td> | 300K |
| 代理商： | LM2937-25 |
θ
is specified numerically by the heatsink manufacturer
in the catalog, or shown in a curve that plots temperature rise
vs power dissipation for the heatsink.
HEATSINKING TO-263 AND SOT-223 PACKAGE PARTS
Both the TO-263 (“S”) and SOT-223 (“MP”) packages use a
copper plane on the PCB and the PCB itself as a heatsink.
To optimize the heat sinking ability of the plane and PCB,
solder the tab of the package to the plane.
Figure 3shows for the TO-263 the measured values of
θ
for different copper area sizes using a typical PCB with 1
ounce copper and no solder mask over the copper area used
for heatsinking.
As shown in the figure, increasing the copper area beyond 1
square inch produces very little improvement. It should also
be observed that the minimum value of
θ
(JA)
for the TO-263
package mounted to a PCB is 32C/W.
As a design aid, Figure 4 shows the maximum allowable
power dissipation compared to ambient temperature for the
TO-263 device (assuming
θ
is 35C/W and the maxi-
mum junction temperature is 125C).
Figure 5 and Figure 6 show the information for the SOT-223
package. Figure 6 assumes a
θ
of 74C/W for 1 ounce
copper and 51C/W for 2 ounce copper and a maximum
junction temperature of 125C.
Please see AN1028 for power enhancement techniques to
be used with the SOT-223 package.
SOT-223 SOLDERING RECOMMENDATIONS
It is not recommended to use hand soldering or wave solder-
ing to attach the small SOT-223 package to a printed circuit
board. The excessive temperatures involved may cause
package cracking.
Either vapor phase or infrared reflow techniques are pre-
ferred soldering attachment methods for the SOT-223 pack-
age.
DS100113-20
FIGURE 3.
θ
(JA)
vs Copper (1 ounce) Area for the
TO-263 Package
DS100113-21
FIGURE 4. Maximum Power Dissipation vs T
AMB
for
the TO-263 Package
DS100113-22
FIGURE 5.
θ
(JA)
vs Copper (2 ounce) Area for the
SOT-223 Package
DS100113-23
FIGURE 6. Maximum Power Dissipation vs T
AMB
for
the SOT-223 Package
7
www.national.com
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PDF描述 |
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| LM2937-3.3 | 400mA and 500mA Voltage Regulators |
| LM2937 | 8-Bit Shift Registers With Output Registers 16-PDIP -40 to 85 |
| LM293D | SINGLE SUPPLY, LOW POWER DUAL COMPARATORS |
| LM293D | Low power dual voltage comparator |
| LM293D | 8-Bit Shift Registers With 3-State Output Registers 16-SOIC -40 to 85 |
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| LM29373ET-2.5 | 制造商:Texas Instruments 功能描述:500 MA LOW DROPOUT REGULATOR - Rail/Tube |
| LM2937EI-12 | 制造商:Texas Instruments 功能描述: |
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| LM2937ES-10 | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20 |
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