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参数资料
| 型号： | MIC49300-0.9WR |
| 厂商： | Micrel Inc |
| 文件页数： | 7/10页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO 0.9V 3A SPAK-5 |
| 标准包装： | 48 |
| 稳压器拓扑结构： | 正，固定式 |
| 输出电压： | 0.9V |
| 输入电压： | 1.4 V ~ 6.5 V |
| 电压 - 压降（标准）： | 0.28V @ 3A |
| 稳压器数量： | 1 |
| 电流 - 输出： | 3A |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | SPAK-5 |
| 供应商设备封装： | S-PAK-5 |
| 包装： | 管件 |
| 产品目录页面： | 1108 (CN2011-ZH PDF) |
| 其它名称： | 576-1810-5 MIC49300-0.9WR-ND |
Micrel, Inc.
Applications Information
The MIC49300 is an ultra-high performance, low dropout
linear regulator designed for high current applications
requiring fast transient response. The MIC49300 utilizes
two input supplies, signi?cantly reducing dropout voltage,
perfect for low-voltage, DC-to-DC conversion. The
MIC49300 requires a minimum of external components
and obtains a bandwidth of up to 10MHz. As a μCap
regulator, the output is tolerant of virtually any type of
capacitor including ceramic and tantalum.
The MIC49300 regulator is fully protected from damage
due to fault conditions, offering linear current limiting and
thermal shutdown.
Bias Supply Voltage
V BIAS , requiring relatively light current, provides power to
the control portion of the MIC49300. V BIAS requires
approximately 33mA for a 1.5A load current. Dropout
conditions require higher currents. Most of the biasing
current is used to supply the base current to the pass
transistor. This allows the pass element to be driven into
saturation, reducing the dropout to 300mV at a 1.5A load
current. Bypassing on the bias pin is recommended to
improve performance of the regulator during line and load
transients. Small ceramic capacitors from VBIAS to
MIC49300
capacitors change value by as much as 50% and 60%,
respectively, over their operating temperature ranges. To
use a ceramic chip capacitor with Y5V dielectric, the
value must be much higher than an X7R ceramic or a
tantalum capacitor to ensure the same capacitance value
over the operating temperature range. Tantalum
capacitors have a very stable dielectric (10% over their
operating temperature range) and can also be used with
this device.
Input Capacitor
An input capacitor of 1μF or greater is recommended
when the device is more than 4 inches away from the
bulk supply capacitance, or when the supply is a battery.
Small, surface-mount, ceramic chip capacitors can be
used for the bypassing. The capacitor should be placed
within 1" of the device for optimal performance. Larger
values will help to improve ripple rejection by bypassing
the input to the regulator, further improving the integrity of
the output voltage.
Thermal Design
Linear regulators are simple to use. The most
complicated design parameters to consider are thermal
characteristics. Thermal design requires the following
application- speci?c parameters:
ground help reduce high frequency noise from being
injected into the control circuitry from the bias rail and are
good design practice. Good bypass techniques typically
include one larger capacitor such as a 1μF ceramic and
smaller valued capacitors such as 0.01μF or 0.001μF in
parallel with that larger capacitor to decouple the bias
supply. The V BIAS input voltage must be 1.6V above the
?
?
?
?
?
Maximum ambient temperature (T A )
Output Current (I OUT )
Output Voltage (V OUT )
Input Voltage (V IN )
Ground Current (I GND )
output voltage with a minimum V BIAS input voltage of 3V.
Input Supply Voltage
V IN provides the high current to the collector of the pass
transistor. The minimum input voltage is 1.4V, allowing
conversion from low voltage supplies.
Output Capacitor
The MIC49300 requires a minimum of output capacitance
to maintain stability. However, proper capacitor selection
is important to ensure desired transient response. The
MIC49300 is speci?cally designed to be stable with
First, calculate the power dissipation of the regulator from
these numbers and the device parameters from this
datasheet.
P D = V IN × I IN + V BIAS × I BIAS – V OUT × I OUT
The input current will be less than the output current at
high output currents as the load increases. The bias
current is a sum of base drive and ground current.
Ground current is constant over load current. Then the
heat sink thermal resistance is determined with this
formula:
? SA ? ? ?
? ?
virtually any capacitance value and ESR. A 1μF ceramic
chip capacitor should satisfy most applications. Output
capacitance can be increased without bound. See Typical
? T J ( MAX ) ? T A
? P D ? ( ? JC ? ? CS )
?
?
Equation 1
Characteristics for examples of load transient response.
X7R dielectric ceramic capacitors are recommended
because of their temperature performance. X7R-type
capacitors change capacitance by 15% over their
operating temperature range and are the most stable
type of ceramic capacitors. Z5U and Y5V dielectric
The heat sink may be signi ?cantly reduced in application
where the maximum input voltage is known and 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
January 22, 2014
7
Revision 3.0
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC49300-1.2BR | 功能描述:IC REG LDO 1.2V 3A SPAK-5 RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 标准包装:3,000 系列:- 稳压器拓扑结构:正，固定式 输出电压:3.8V 输入电压:最高 16V 电压 - 压降（标准）:0.3V @ 80mA 稳压器数量:1 电流 - 输出:80mA 电流 - 限制（最小）:- 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:带卷 (TR) 其它名称:MIC5203-3.8BM5TRMIC5203-3.8BM5TR-ND |
| MIC49300-1.2BR TR | 功能描述:IC REG LDO 1.2V 3A SPAK-5 RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 标准包装:3,000 系列:- 稳压器拓扑结构:正，固定式 输出电压:3.8V 输入电压:最高 16V 电压 - 压降（标准）:0.3V @ 80mA 稳压器数量:1 电流 - 输出:80mA 电流 - 限制（最小）:- 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:带卷 (TR) 其它名称:MIC5203-3.8BM5TRMIC5203-3.8BM5TR-ND |
| MIC49300-1.2WR | 功能描述:低压差稳压器 - LDO Dual Supply, LV 3.0A LDO(ROHS Compliant) RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20 |
| MIC49300-1.2WR TR | 功能描述:低压差稳压器 - LDO Dual Supply, LV 3.0A LDO(ROHS Compliant) RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20 |
| MIC49300-1.2WRTR | 制造商:Micrel Semiconductor 功能描述:Cut Tape |
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