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參數(shù)資料
| 型號(hào)： | TK71548 |
| 廠商： | TOKO Inc. |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | LOW DROPOUT VOLTAGE REGULATOR |
| 中文描述： | 低壓差穩(wěn)壓器 |
| 文件頁(yè)數(shù)： | 9/13頁(yè) |
| 文件大?。?/td> | 76K |
| 代理商： | TK71548 |
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January 1999 TOKO, Inc.
Page 9
TK715xx
DEFINITION AND EXPLANATION OF TECHNICAL TERMS (CONT.)
determine the power dissipation for shutdown when
mounted, attach the device on the actual PCB and
deliberately increase the output current (or raise the input
voltage) until the thermal protection circuit is activated.
Calculate the power dissipation of the device by subtracting
the output power from the input power. These
measurements should allow for the ambient temperature
of the PCB. The value obtained from P
D
/(150
°
C - T
A
) is the
derating factor. The PCB mounting pad should provide
maximum thermal conductivity in order to maintain low
device temperatures. As a general rule, the lower the
temperature, the better the reliability of the device. The
thermal resistance when mounted is expressed as follows:
T
j
= 0
jA
x P
D
+ T
A
For Toko ICs, the internal limit for junction temperature is
150
°
C. If the ambient temperature (T
A
) is 25
°
C, then:
150
°
C = 0
jA
x P
D
+ 25
°
C
0
jA
= 125
°
C/ P
D
P
D
is the value when the thermal sensor is activated. A
simple way to determine P
D
is to calculate V
IN
x I
IN
when
the output side is shorted. Input current gradually falls as
temperature rises. You should use the value when thermal
equilibrium is reached.
The range of usable currents can also be found from the
graph below.
Procedure:
1)
2)
Find P
D
P
D1
is taken to be P
D
x (~ 0.8 - 0.9)
3)
4)
Plot P
D1
against 25
°
C
Connect P
D1
to the point corresponding to the 150
°
C
with a straight line.
In design, take a vertical line from the maximum
operating temperature (e.g., 75
°
C) to the derating
curve.
Read off the value of P
D
against the point at which the
vertical line intersects the derating curve. This is taken
as the maximum power dissipation, D
PD
.
5)
6)
The maximum operating current is:
I
OUT
= (D
PD
/ (V
IN(MAX)
-
V
OUT
)
SOT-23-3 POWER DISSIPATION CURVE
PD
DPD
25
50
75
150
(mW)
TA (
°
C)
3
6
5
4
0 50 100 150
TA (
°
C)
P
0
300
500
100
200
400
MOUNTED AS
SHOWN
FREE AIR
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PDF描述 |
|---|---|
| TK71548AS | LOW DROPOUT VOLTAGE REGULATOR |
| TK71548ASCL | LOW DROPOUT VOLTAGE REGULATOR |
| TK71548S | LOW DROPOUT VOLTAGE REGULATOR |
| TK71548SCL | LOW DROPOUT VOLTAGE REGULATOR |
| TK71549 | LOW DROPOUT VOLTAGE REGULATOR |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TK71548AS | 制造商:TOKO 制造商全稱:TOKO, Inc 功能描述:LOW DROPOUT VOLTAGE REGULATOR |
| TK71548ASCL | 制造商:TOKO 制造商全稱:TOKO, Inc 功能描述:LOW DROPOUT VOLTAGE REGULATOR |
| TK71548ASCL/48 | 制造商:TOKO 制造商全稱:TOKO, Inc 功能描述:LOW DROPOUT VOLTAGE REGULATOR |
| TK71548S | 制造商:TOKO 制造商全稱:TOKO, Inc 功能描述:LOW DROPOUT VOLTAGE REGULATOR |
| TK71548SCL | 制造商:TOKO 制造商全稱:TOKO, Inc 功能描述:LOW DROPOUT VOLTAGE REGULATOR |
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