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參數(shù)資料
| 型號： | MIC29301-12BU |
| 廠商： | MICREL INC |
| 元件分類： | 固定正電壓單路輸出LDO穩(wěn)壓器 |
| 英文描述： | High-Current Low-Dropout Regulators |
| 中文描述： | 12 V FIXED POSITIVE LDO REGULATOR, 0.6 V DROPOUT, PSSO5 |
| 封裝： | TO-263, D2PAK-5 |
| 文件頁數(shù)： | 9/23頁 |
| 文件大?。?/td> | 708K |
| 代理商： | MIC29301-12BU |
Micrel, Inc.
MIC29150/29300/29500/29750
May 2010
17
M9999-050510-B
Application Information
The
MIC29150/29300/29500/29750
are
high
performance low-dropout voltage regulators suitable for
all
moderate
to
high-current
voltage
regulator
applications. Their 350mV to 425mV typical dropout
voltage at full load make them especially valuable in
battery powered systems and as high efficiency noise
filters in “post-regulator” applications. Unlike older NPN-
pass transistor designs, where the minimum dropout
voltage is limited by the base-emitter voltage drop and
collector-emitter saturation voltage, dropout performance
of the PNP output of these devices is limited merely by
the low VCE saturation voltage.
A trade-off for the low-dropout voltage is a varying base
driver requirement. But Micrel’s Super eta PNP
process reduces this drive requirement to merely 1% of
the load current.
The MIC29150/29300/29500/29750 family of regulators
are fully protected from damage due to fault conditions.
Current limiting is provided. This limiting is linear; output
current under overload conditions is constant. Thermal
shutdown disables the device when the die temperature
exceeds
the
125°C
maximum
safe
operating
temperature. Transient protection allows device (and
load) survival even when the input voltage spikes
between –20V and +60V. When the input voltage
exceeds about 35V to 40V, the over voltage sensor
temporarily disables the regulator. The output structure
of these regulators allows voltages in excess of the
desired output voltage to be applied without reverse
current flow. MIC29xx1 and MIC29xx2 versions offer a
logic level ON/OFF control: when disabled, the devices
draw nearly zero current.
An additional feature of this regulator family is a common
pinout: a design’s current requirement may change up or
down yet use the same board layout, as all of these
regulators have identical pinouts.
MIC29XXX
OUT
VOUT
IN
GND
VIN
Figure 3. Linear regulators require only two capacitors for
operation.
Thermal Design
Linear regulators are simple to use. The most
complicated design parameters to consider are thermal
characteristics. Thermal design requires the following
application-specific parameters:
Maximum ambient temperature, TA
Output Current, IOUT
Output Voltage, VOUT
Input Voltage, VIN
First, we calculate the power dissipation of the regulator
from these numbers and the device parameters from this
datasheet.
(
)
OUT
IN
OUT
D
V
1.01
I
P
=
Where the ground current is approximated by 1% of IOUT.
Then the heat sink thermal resistance is determined with
this formula:
()
CS
JC
D
A
JMAX
SA
P
T
θ
+
θ
=
θ
Where TJMAX ≤ 125°C and θCS is between 0 and 2°C/W.
The heat sink may be significantly reduced in
applications where the minimum input voltage is known
and is large compared with the dropout voltage. Use a
series input resistor to drop excessive voltage and
distribute the heat between this resistor and the
regulator. The low-dropout properties of Micrel Super
eta PNP
regulators allow very significant reductions in
regulator power dissipation and the associated heat sink
without compromising performance. When this technique
is employed, a capacitor of at least 0.1F is needed
directly between the input and regulator ground.
Please refer to Application Note 9 and Application Hint
17 for further details and examples on thermal design
and heat sink specification.
With no heat sink in the application, calculate the
junction temperature to determine the maximum power
dissipation that will be allowed before exceeding the
maximum junction temperature of the MIC29152. The
maximum power allowed can be calculated using the
thermal resistance (θJA) of the D-Pak adhering to the
following criteria for the PCB design: 2 oz. copper and
100mm
2 copper area for the MIC29152.
For example, given an expected maximum ambient
temperature (TA) of 75°C with VIN = 3.3V, VOUT = 2.5V,
and IOUT = 1.5A, first calculate the expected PD using
Equation (1);
PD=(3.3V–2.5V)1.5A–(3.3V)(0.016A)=1.1472W
Next, calcualte the junction temperature for the expected
power dissipation.
TJ=(θJA×PD)+TA=(56°C/W×1.1472W)+75°C=139.24°C
Now determine the maximum power dissipation allowed
that would not exceed the IC’s maximum junction
temperature (125
°C) without the useof a heat sink by
PD(MAX)=(TJ(MAX)–TA)/θJA=(125°C–75°C)/(56°C/W) =0.893W
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MIC29301-12BU TR | 功能描述:IC REG LDO 12V 3A TO-263-5 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 標準包裝:3,000 系列:- 穩(wěn)壓器拓撲結(jié)構:正，固定式 輸出電壓:3.8V 輸入電壓:最高 16V 電壓 - 壓降（標準）:0.3V @ 80mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:80mA 電流 - 限制（最小）:- 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應商設備封裝:SOT-23-5 包裝:帶卷 (TR) 其它名稱:MIC5203-3.8BM5TRMIC5203-3.8BM5TR-ND |
| MIC29301-12WT | 功能描述:低壓差穩(wěn)壓器 - LDO 3.0A LDO Fixed Voltage + Flag + Shutdown (RoHS Compliant) 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 |
| MIC29301-12WU | 功能描述:低壓差穩(wěn)壓器 - LDO 3.0A LDO Fixed Voltage + Flag + Shutdown RoHS Compliant 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 |
| MIC29301-12WU TR | 功能描述:低壓差穩(wěn)壓器 - LDO 3.0A LDO Fixed Voltage + Flag + Shutdown RoHS Compliant 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 |
| MIC29301-3.3BT | 功能描述:IC REG LDO 3.3V 3A TO-220-5 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 標準包裝:3,000 系列:- 穩(wěn)壓器拓撲結(jié)構:正，固定式 輸出電壓:3.8V 輸入電壓:最高 16V 電壓 - 壓降（標準）:0.3V @ 80mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:80mA 電流 - 限制（最小）:- 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應商設備封裝:SOT-23-5 包裝:帶卷 (TR) 其它名稱:MIC5203-3.8BM5TRMIC5203-3.8BM5TR-ND |
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