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参数资料
| 型号： | MIC3975BMM |
| 厂商： | Micrel Inc |
| 文件页数： | 9/12页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO ADJ .75A 8-MSOP |
| 标准包装： | 100 |
| 稳压器拓扑结构： | 正，可调式 |
| 输出电压： | 1.24 V ~ 16 V |
| 输入电压： | 2.25 V ~ 16 V |
| 电压 - 压降（标准）： | 0.3V @ 750mA |
| 稳压器数量： | 1 |
| 电流 - 输出： | 750mA（最小） |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 供应商设备封装： | 8-MSOP |
| 包装： | 管件 |
V IN
V OUT
C OUT
C IN
MIC3975
Applications Information
The MIC3975 is a high-performance low-dropout voltage regu-
lator suitable for moderate to high-current voltage regulator
applications. Its 500mV dropout voltage at full load and over-
temperature makes it especially valuable in battery-powered
systems and as high-ef?ciency noise ?lters in post-regulator
applications. Unlike older NPN-pass transistor designs, where
the minimum dropout voltage is limited by the base-to-emit-
ter voltage drop and collector-to-emitter saturation voltage,
dropout performance of the PNP output of these devices is
limited only by the low V CE saturation voltage.
A trade-off for the low dropout voltage is a varying base drive
requirement. Micrel’s Super β eta PNP? process reduces this
drive requirement to only 2% of the load current.
The MIC3975 regulator is fully protected from damage due to
fault conditions. Linear current limiting is provided. Output cur-
rent during overload conditions is constant. Thermal shutdown
disables the device when the die temperature exceeds the
maximum safe operating temperature. Transient protection
allows device (and load) survival even when the input volt-
age spikes above and below nominal. The output structure
of these regulators allows voltages in excess of the desired
output voltage to be applied without reverse current ?ow.
MIC3975x.x
IN OUT
GND
Figure 1. Capacitor Requirements
Output Capacitor
The MIC3975 requires an output capacitor for stable opera-
tion. As a μ Cap LDO, the MIC3975 can operate with ceramic
output capacitors as long as the amount of capacitance is
10 μ F or greater. For values of output capacitance lower than
10 μ F, the recommended ESR range is 200m ? to 2 ? . The
minimum value of output capacitance recommended for the
MIC3975 is 4.7 μ F.
For 10 μ F or greater the ESR range recommended is less than
1 ? . Ultra-low ESR ceramic capacitors are recommended
for output capacitance of 10 μ F or greater to help improve
transient response and noise reduction at high frequency.
X7R/X5R dielectric-type ceramic capacitors are recom-
mended 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 capacitors change value
by as much as 50% and 60% respectively over their operat-
ing temperature ranges. To use a ceramic chip capacitor with
Y5V dielectric, the value must be much higher than an X7R
ceramic capacitor to ensure the same minimum capacitance
over the equivalent operating temperature range.
Micrel
Input Capacitor
An input capacitor of 1μF or greater is recommended when
the device is more than 4 inches away from the bulk ac supply
capacitance or when the supply is a battery. Small, surface
mount, ceramic chip capacitors can be used for bypassing.
Larger values will help to improve ripple rejection by bypass-
ing the input to the regulator, further improving the integrity
of the output voltage.
Error Flag
The MIC3975 features an error ?ag (FLG), which monitors
the output voltage and signals an error condition when this
voltage drops 5% below its expected value. The error ?ag is
an open-collector output that pulls low under fault conditions
and may sink up to 10mA. Low output voltage signi?es a
number of possible problems, including an overcurrent fault
(the device is in current limit) or low input voltage. The ?ag
output is inoperative during overtemperature conditions. A
pull-up resistor from FLG to either V IN or V OUT is required
for proper operation. For information regarding the minimum
and maximum values of pull-up resistance, refer to the graph
in the typical characteristics section of the data sheet.
Enable Input
The MIC3975 features an active-high enable input (EN) that
allows on-off control of the regulator. Current drain reduces to
“zero” when the device is shutdown, with only microamperes
of leakage current. The EN input has TTL/CMOS compatible
thresholds for simple logic interfacing. EN may be directly tied
to V IN and pulled up to the maximum supply voltage
Transient Response and 3.3V to 2.5V or 2.5V to 1.8V or
1.65V Conversion
The MIC3975 has excellent transient response to variations in
input voltage and load current. The device has been designed
to respond quickly to load current variations and input voltage
variations. Large output capacitors are not required to obtain
this performance. A standard 10μF output capacitor, is all
that is required. Larger values help to improve performance
even further.
By virtue of its low-dropout voltage, this device does not satu-
rate into dropout as readily as similar NPN-based designs.
When converting from 3.3V to 2.5V or 2.5V to 1.8V or 1.65V,
the NPN based regulators are already operating in dropout,
with typical dropout requirements of 1.2V or greater. To convert
down to 2.5V or 1.8V without operating in dropout, NPN-based
regulators require an input voltage of 3.7V at the very least.
The MIC3975 regulator will provide excellent performance
with an input as low as 3.0V or 2.5V respectively. This gives
the PNP based regulators a distinct advantage over older,
NPN based linear regulators.
Minimum Load Current
The MIC3975 regulator is speci?ed between ?nite loads. If
the output current is too small, leakage currents dominate
and the output voltage rises. A 10mA minimum load current
is necessary for proper regulation.
February 2005
9
MIC3975
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC3975BMM TR | 功能描述:IC REG LDO ADJ .75A 8-MSOP 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 |
| MIC3975YMM | 功能描述:低压差稳压器 - LDO 750mA uCap LDO in Power MSOP-8 Pkg(Lead Free) 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 |
| MIC3975YMM TR | 功能描述:低压差稳压器 - LDO 750mA uCap LDO in Power MSOP-8 Pkg(Lead Free) 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 |
| MIC4043 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:Low-Voltage Secondary-Side Shunt Regulator |
| MIC4043_02 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:Low-Voltage Secondary-Side Shunt Regulator |
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