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參數(shù)資料
| 型號： | LP2952A |
| 廠商： | National Semiconductor Corporation |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Adjustable Micropower Low-Dropout Voltage Regulators |
| 中文描述： | 可調(diào)微功率低壓差穩(wěn)壓器 |
| 文件頁數(shù)： | 13/22頁 |
| 文件大?。?/td> | 1050K |
| 代理商： | LP2952A |
Application Hints
(Continued)
The next parameter which must be calculated is the maxi-
mum allowable temperature rise, T
R
(max). This is calculated
by using the formula:
T
R
(max) = T
J
(max) T
A
(max)
θ
(J–A)
= T
R
(max)/P(max)
where: T
(max)
is
the
maximum
temperature
T
A
(max) is the maximum ambient temperature
Using the calculated values for T
R
(max) and P(max), the
required value for junction-to-ambient thermal resistance,
θ
(J–A)
, can now be found:
The heatsink is made using the PC board copper. The heat
is conducted from the die, through the lead frame (inside the
part), and out the pins which are soldered to the PC board.
The pins used for heat conduction are given in
Table 1
.
allowable
junction
TABLE 1. Heat Conducting Pins
Part
Package
14-Pin DIP
Pins
3, 4, 5,
10, 11, 12
LP2952IN, LP2952AIN,
LP2952IN-3.3,
LP2952AIN-3.3
LP2953IN, LP2953AIN,
LP2953IN-3.3,
LP2953AIN-3.3
LP2952IM, LP2952AIM,
LP2952IM-3.3,
LP2952AIM-3.3,
LP2953IM, LP2953AIM,
LP2953IM-3.3,
LP2953AIM-3.3
16-Pin DIP
4, 5, 12, 13
16-Pin Surface
Mount
1, 8, 9, 16
Figure 2
shows copper patterns which may be used to
dissipate heat from the LP2952 and LP2953.
Table 2
shows
some values of junction-to-ambient thermal resistance (
θ
J–A
)
for values of L and W for 1 oz. copper.
TABLE 2. Thermal Resistance for Various Copper
Heatsink Patterns
Package
16-Pin DIP
L (in.)
1
2
3
4
6
1
2
3
1
2
3
6
4
2
H (in.)
0.5
1
1.5
0.19
0.19
0.5
1
1.5
0.5
1
1.5
0.19
0.19
0.19
θ
J–A
(C/W)
70
60
58
66
66
65
51
49
83
70
67
69
71
73
14-Pin DIP
Surface Mount
HEATSINK REQUIREMENTS (Military Temperature
Range Devices)
The
maximum
allowable
LP2953AMJ is limited by the maximum junction temperature
(+150C) and the two parameters that determine how quickly
heat flows away from the die:
the ambient temperature and
the junction-to-ambient thermal resistance of the part
.
power
dissipation
for
the
01112707
FIGURE 1. P
= (V
V
) I
L
+ (V
IN
) I
G
Current/Voltage Diagram
01112708
* For best results, use L = 2H
** 14-Pin DIP is similar, refer to
Table 1
for pins designated for
heatsinking.
FIGURE 2. Copper Heatsink Patterns
L
www.national.com
13
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP2952AI | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Adjustable Micropower Low-Dropout Voltage Regulators |
| LP2952AI-3.3 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Adjustable Micropower Low-Dropout Voltage Regulators |
| LP2952AIM | 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 |
| LP2952AIM/NOPB | 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 |
| LP2952AIM-3.3 | 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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