- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄384601 > LM883K (National Semiconductor Corporation) 3-Terminal Adjustable Regulator PDF資料下載
參數(shù)資料
| 型號(hào)： | LM883K |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | 3-Terminal Adjustable Regulator |
| 中文描述： | 三端可調(diào)穩(wěn)壓器 |
| 文件頁數(shù)： | 10/25頁 |
| 文件大?。?/td> | 697K |
| 代理商： | LM883K |
Application Hints
(Continued)
The LM317 regulators have internal thermal shutdown to
protect the device from over-heating. Under all possible
operating conditions, the junction temperature of the LM317
must be within the range of 0C to 125C. A heatsink may be
required depending on the maximum power dissipation and
maximum ambient temperature of the application. To deter-
mine if a heatsink is needed, the power dissipated by the
regulator, P
D
, must be calculated:
I
IN
= I
L
+ I
G
P
D
= (V
IN
V
OUT
) I
L
+ V
IN
I
G
Figure 8
shows the voltage and currents which are present in
the circuit.
The next parameter which must be calculated is the maxi-
mum allowable temperature rise, T
R
(max):
T
R
(max) = T
J
(max) T
A
(max)
where T
(max) is the maximum allowable junction tempera-
ture (125C), and T
(max) is the maximum ambient tem-
perature which will be encountered in the application.
Using the calculated values for T
(max) and P
, the maxi-
mum allowable value for the junction-to-ambient thermal
resistance (
θ
JA
) can be calculated:
θ
JA
= T
R
(max)/P
D
If the maximum allowable value for
θ
is found to be
≥
92C/W (Typical Rated Value) 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
θ
JA
falls below these limits, a heatsink is required.
As a design aid,
Table 1
shows the value of the
θ
of
TO-252 for different heatsink area. The copper patterns that
we used to measure these
θ
JA
s are shown at the end of the
Application Notes Section.
Figure 9
reflects the same test
results as what are in the
Table 1
Figure 10
shows the maximum allowable power dissipation
vs. ambient temperature for the TO-252 device.
Figure 11
shows the maximum allowable power dissipation vs. copper
area (in
2
) for the TO-252 device. Please see AN1028 for
power enhancement techniques to be used with SOT-223
and TO-252 packages.
TABLE 1.
θ
JA
Different Heatsink Area
Layout
Copper Area
Thermal Resistance
(
θ
JA
C/W) TO-252
103
87
60
54
52
47
84
70
63
Top Side (in
2
)*
0.0123
0.066
0.3
0.53
0.76
1
0
0
0
Bottom Side (in
2
)
0
0
0
0
0
0
0.2
0.4
0.6
1
2
3
4
5
6
7
8
9
00906357
FIGURE 6.
θ
(JA)
vs Copper (2 ounce) Area for the
SOT-223 Package
00906358
FIGURE 7. Maximum Power Dissipation vs T
AMB
for
the SOT-223 Package
00906360
FIGURE 8. Power Dissipation Diagram
L
www.national.com
10
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM883HVKSTL | 3-Terminal Adjustable Regulator |
| LM883 | Voltage Regulators |
| LM9073 | Dual High Current Low-Dropout System Regulator(雙路高電流低壓差系統(tǒng)穩(wěn)壓器) |
| LM94022BIMGX | 1.5V, SC70, Multi-Gain Analog Temperature Sensor with Class-AB Output |
| LM94022 | 1.5V, SC70, Multi-Gain Analog Temperature Sensor with Class-AB Output |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM883W | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Operational Amplifier |
| LM8850 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Evaluation Board Application Note working demonstration |
| LM8850URE/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM8850UREV/NOPB | 功能描述:BOARD EVAL LM8850 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評(píng)估板 - DC/DC 與 AC/DC（離線）SMPS 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:DC/DC，步降 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:3.3V 電流 - 輸出:3A 輸入電壓:4.5 V ~ 28 V 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):降壓 頻率 - 開關(guān):250kHz 板類型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名稱:497-12113STEVAL-ISA094V1-ND |
| LM8850URX/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 High-Perf,Step-Up DC-DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。