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参数资料
| 型号： | MIC5225-3.3YM5TR |
| 厂商： | MICREL INC |
| 元件分类： | 固定正电压单路输出LDO稳压器 |
| 英文描述： | 3.3 V FIXED POSITIVE LDO REGULATOR, 0.45 V DROPOUT, PDSO5 |
| 封装： | LEAD FREE, SOT-23, 5 PIN |
| 文件页数： | 7/9页 |
| 文件大小： | 215K |
| 代理商： | MIC5225-3.3YM5TR |
Micrel, Inc.
MIC5225
July 2008
7
M9999-072908-A
Application Information
Enable/Shutdown
The MIC5225 comes with an active-high enable pin that
allows the regulator to be disabled. Forcing the enable
pin lows disables the regulator and sends it into a “zero”
off-mode current state. In this state, current consumed
by the regulator goes nearly to zero. Forcing the enable
pin high enables the output voltage.
Input Capacitor
The MIC5225 has a wide input voltage capability up to
16V. The input capacitor must be rated to sustain
voltages that may be used on the input. An input
capacitor may be required when the device is not near
the source power supply or when supplied by a battery.
Small, surface mount, ceramic capacitors can be used
for bypassing. Larger value may be required if the
source supply has high ripple.
Output Capacitor
The MIC5225 requires an output capacitor for stability.
The design requires 1.0F or greater on the output to
maintain stability. The design is optimized for use with
low-ESR ceramic chip capacitors. High ESR capacitors
may cause high frequency oscillation. The maximum
recommended ESR is 300m. The output capacitor can
be increased, but performance has been optimized for a
1.0F ceramic output capacitor and does not improve
significantly with the use of a larger capacitor.
X7R/X5R
dielectric-type
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 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 capacitor to ensure the same minimum
capacitance over the equivalent operating temperature
range.
No-Load Stability
The MIC5225 will remain stable and in regulation with no
load unlike many other voltage regulators. This is
especially
important
in
CMOS
RAM
keep-alive
applications.
Thermal Consideration
The MIC5225 is designed to provide 150mA of
continuous current in a very small package. Maximum
power dissipation can be calculated based on the output
current and the voltage drop across the part. To
determine the maximum power dissipation of the
package, use the junction-to-ambient thermal resistance
of the device and the following basic equation:
PD(MAX) = (TJ(MAX) – TA)/θJA
TJ(MAX) is the maximum junction temperature of the die,
125
°C, and T
A is the ambient operating temperature. θJA
is layout dependent; Table 1 shows examples of the
junction-to-ambient thermal resistance for the MIC5225.
Package
θJA Recommended
Minimum Footprint
SOT-23-5
235
oC/W
Table 1. SOT-23-5 Thermal Resistance
The actual power dissipation of the regulator circuit can
be determined using the equation:
PD = (VIN – VOUT)IOUT + VINIGND
Substituting PD(MAX for PD and solving for the operating
conditions that are critical to the application will give the
maximum operating conditions for the regulator circuit.
For example, when operating the MIC5225-3.0BMM at
50
°C with a minimum footprint layout, the maximum input
voltage for a set output current can be determined as
follows:
PD(MAX) = (125
oC – 50oC)/ 235oC/W
PD(MAX) = 319mW
The junction-to-ambient thermal resistance for the
minimum footprint is 235
°C/W, from Table 1. The
maximum power dissipation must not be exceeded for
proper operation. Using the output voltage of 3.0V, and
an output current of 150mA, the maximum input voltage
can be determined.
319mW = (VIN – 3.0V)150mA + VIN × 3.0mA
319mW = VIN × 153mA – 450mW
769mW = VIN × 153mA
VIN(MAX) = 5.02V
Therefore, a 3.0V application at 150mA of output current
can accept a maximum input voltage of 5.02V in the
SOT-23-5 package. For a full discussion of heat sinking
and thermal effects on the voltage regulators, refer to the
Regulator Thermals section of Micrel’s Designing with
Low-Dropout
Voltage
Regulators
handbook:
http://www.onfulfillment.com/estore/pdf_download.asp?
s=2243381&p=18&pdf=842935-iecjdf-bicadii
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC5225-5.0YM5 | 制造商:RF Micro Devices Inc 功能描述: |
| MIC5225-5.0YM5 TR | 功能描述:低压差稳压器 - LDO High Vin, Low Iq Regulator (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 |
| MIC5225-5.0YM5TR | 制造商:Micrel 功能描述:LDO Regulator 150mA, 5V |
| MIC5225-5.0YM5-TR | 功能描述:Linear Voltage Regulator IC Positive Fixed 1 Output 5V 150mA SOT-23-5 制造商:microchip technology 系列:- 包装:剪切带（CT） 零件状态:有效 稳压器拓扑:正，固定式 电压 - 输出:5V 电流 - 输出:150mA 电压 - 跌落（典型值）:0.31V @ 150mA 稳压器数:1 电压 - 输入:最高 16V 电流 - 限制（最小值）:- 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商器件封装:SOT-23-5 标准包装:1 |
| MIC5225YM5 | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: |
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