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參數(shù)資料
| 型號： | LT1521CST-5 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Cap-Free, NMOS, 150mA Low Dropout Regulator with Reverse Current Protection |
| 中文描述： | 5 V FIXED POSITIVE LDO REGULATOR, 0.75 V DROPOUT, PDSO4 |
| 封裝： | PLASTIC, SOT-223, 4 PIN |
| 文件頁數(shù)： | 11/16頁 |
| 文件大?。?/td> | 294K |
| 代理商： | LT1521CST-5 |
11
LT1521/LT1521-3
LT1521-3.3/LT1521-5
APPLICATIO
S I
N
FOR
ATIO
U
Table 3. SOT-223 Package
(Thermal Resistance Junction-to-Tab 20
°
C/W)
COPPER AREA
TOPSIDE*
BACKSIDE
BOARD AREA
2500mm
2
2500mm
2
2500mm
2
1000mm
2
2500mm
2
2500mm
2
225mm
2
2500mm
2
2500mm
2
100mm
2
2500mm
2
2500mm
2
1000mm
2
1000mm
2
1000mm
2
1000mm
2
0
1000mm
2
W
U
is required to prevent oscillations. The LT1521 is a
micropower device and output transient response will be
a function of output capacitance. See the Transient
Response curves in the Typical Performance Characteris-
tics. Larger values of output capacitance will decrease the
peak deviations and provide improved output transient
response for larger load current deltas. Bypass capaci-
tors, used to decouple individual components powered by
the LT1521, will increase the effective value of the output
capacitor.
Protection Features
The LT1521 incorporates several protection features which
make it ideal for use in battery-powered circuits. In
addition to the normal protection features associated with
monolithic regulators, such as current limiting and ther-
mal limiting, the device is protected against reverse input
voltages, reverse output voltages and reverse voltages
from output to input.
Current limit protection and thermal overload protection
are intended to protect the device against current overload
conditions at the output of the device. For normal opera-
tion, the junction temperatures should not exceed 125
°
C.
The input of the device will withstand reverse voltages of
20V. Current flow into the device will be limited to less
than 1mA (typically less than 100
μ
A) and no negative
voltage will appear at the output. The device will protect
both itself and the load. This provides protection against
batteries that can be plugged in backward.
For fixed voltage versions of the device, the output can be
pulled below ground without damaging the device. If the
input is left open circuit or grounded, the output can be
pulled below ground by 20V. The output will act like an
open circuit, no current will flow out of the pin. If the input
is powered by voltage source, the output will source the
short-circuit current of the device and will protect itself by
thermal limiting. For the adjustable version of the device,
the output pin is internally clamped at one diode drop
below ground. Reverse current for the adjustable device
must be limited to 5mA.
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)
50
°
C/W
50
°
C/W
58
°
C/W
64
°
C/W
57
°
C/W
60
°
C/W
* Tab of device attached to topside copper.
Calculating Junction Temperature
Example: Given an output voltage of 3.3V, an input voltage
range of 4.5V to 7V, an output current range of 0mA to
150mA and a maximum ambient temperature of 50
°
C,
what will the maximum junction temperature be
The power dissipated by the device will be equal to:
I
OUT(MAX)
(V
IN(MAX)
– V
OUT
) + I
GND
(
V
IN(MAX)
)
Where,
I
OUT(MAX)
= 150mA
V
IN(MAX)
= 7V
I
GND
at (I
OUT
= 150mA, V
IN
= 7V) = 2.1mA
So,
P = 150mA(7V – 3.3V) + (2.1mA)(7V) = 0.57W
If we use a SOT-223 package, then the thermal resistance
will be in the range of 50
°
C/W to 65
°
C/W depending on the
copper area. So the junction temperature rise above
ambient will be approximately equal to:
0.57W(60
°
C/W) = 34.2
°
C
The maximum junction temperature will then be equal to the
maximum junction temperature rise above ambient plus the
maximum ambient temperature or:
T
JMAX
= 50
°
C + 34.2
°
C = 84.2
°
C
Output Capacitance and Transient Performance
The LT1521 is designed to be stable with a wide range of
output capacitors. A minimum output capacitor of 1.5
μ
F
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| LT1521IS8 | Cap-Free, NMOS, 150mA Low Dropout Regulator with Reverse Current Protection |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LT1521CST-5#PBF | 功能描述:IC REG LDO 5V .3A SOT223-3 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 標準包裝:1 系列:- 穩(wěn)壓器拓撲結構:正，固定式 輸出電壓:8V 輸入電壓:10.5 V ~ 23 V 電壓 - 壓降（標準）:1.7V @ 40mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:100mA（最小值） 電流 - 限制（最?。?- 工作溫度:0°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 供應商設備封裝:8-SOIC 包裝:剪切帶 (CT) 產品目錄頁面:1075 (CN2011-ZH PDF) 其它名稱:296-24390-1 |
| LT1521CST-5#TR | 功能描述:IC REG LDO 5V .3A SOT223-3 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 產品培訓模塊:More Information on LDOs 標準包裝:50 系列:- 穩(wěn)壓器拓撲結構:正，固定式 輸出電壓:3.3V 輸入電壓:最高 15V 電壓 - 壓降（標準）:1.1V @ 800mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:800mA 電流 - 限制（最小）:800mA 工作溫度:0°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:TO-263-4，D²Pak（3 引線+接片），TO-263AA 供應商設備封裝:D2PAK-3 包裝:管件 |
| LT1521CST-5#TRPBF | 功能描述:IC REG LDO 5V .3A SOT223-3 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 產品培訓模塊:More Information on LDOs 標準包裝:50 系列:- 穩(wěn)壓器拓撲結構:正，固定式 輸出電壓:3.3V 輸入電壓:最高 15V 電壓 - 壓降（標準）:1.1V @ 800mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:800mA 電流 - 限制（最小）:800mA 工作溫度:0°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:TO-263-4，D²Pak（3 引線+接片），TO-263AA 供應商設備封裝:D2PAK-3 包裝:管件 |
| LT1521CST-5PBF | 制造商:Linear Technology 功能描述:LT1521CST-5PBF |
| LT1521CST8-3 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
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