参数资料
| 型号： | LMR10510YSD/NOPB |
| 厂商： | National Semiconductor |
| 文件页数： | 11/26页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1A 6LLP |
| 标准包装： | 1,000 |
| 系列： | SIMPLE SWITCHER® |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.6 V ~ 4.5 V |
| 输入电压： | 3 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 3MHz |
| 电流 - 输出： | 1A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 6-WDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 6-LLP-EP（3x3） |
SNVS727B – OCTOBER 2011 – REVISED APRIL 2013
When selecting an inductor, make sure that it is capable of supporting the peak output current without saturating.
Inductor saturation will result in a sudden reduction in inductance and prevent the regulator from operating
correctly. Because of the speed of the internal current limit, the peak current of the inductor need only be
specified for the required maximum output current. For example, if the designed maximum output current is 1.0A
and the peak current is 1.25A, then the inductor should be specified with a saturation current limit of > 1.25A.
There is no need to specify the saturation or peak current of the inductor at the 1.75A typical switch current limit.
The difference in inductor size is a factor of 5. Because of the operating frequency of the LMR10510, ferrite
based inductors are preferred to minimize core losses. This presents little restriction since the variety of ferrite-
based inductors is huge. Lastly, inductors with lower series resistance (R DCR ) will provide better operating
efficiency. For recommended inductors see Example Circuits: LMR10510X Design Example 1 LMR10510X
INPUT CAPACITOR
An input capacitor is necessary to ensure that V IN does not drop excessively during switching transients. The
primary specifications of the input capacitor are capacitance, voltage, RMS current rating, and ESL (Equivalent
Series Inductance). The recommended input capacitance is 22 μF.The input voltage rating is specifically stated
by the capacitor manufacturer. Make sure to check any recommended deratings and also verify if there is any
significant change in capacitance at the operating input voltage and the operating temperature. The input
capacitor maximum RMS input current rating (I RMS-IN ) must be greater than:
I RMS_IN D I OUT2 (1-D) +
' i 2
3
Neglecting inductor ripple simplifies the above equation to:
I RMS_IN = I OUT x D(1 - D)
It can be shown from the above equation that maximum RMS capacitor current occurs when D = 0.5. Always
calculate the RMS at the point where the duty cycle D is closest to 0.5. The ESL of an input capacitor is usually
determined by the effective cross sectional area of the current path. A large leaded capacitor will have high ESL
and a 0805 ceramic chip capacitor will have very low ESL. At the operating frequencies of the LMR10510,
leaded capacitors may have an ESL so large that the resulting impedance (2 π fL) will be higher than that required
to provide stable operation. As a result, surface mount capacitors are strongly recommended.
Sanyo POSCAP, Tantalum or Niobium, Panasonic SP, and multilayer ceramic capacitors (MLCC) are all good
choices for both input and output capacitors and have very low ESL. For MLCCs it is recommended to use X7R
or X5R type capacitors due to their tolerance and temperature characteristics. Consult capacitor manufacturer
datasheets to see how rated capacitance varies over operating conditions.
OUTPUT CAPACITOR
The output capacitor is selected based upon the desired output ripple and transient response. The initial current
of a load transient is provided mainly by the output capacitor. The output ripple of the converter is:
' V OUT = ' I L R ESR +
1
8 x F SW x C OUT
When using MLCCs, the ESR is typically so low that the capacitive ripple may dominate. When this occurs, the
output ripple will be approximately sinusoidal and 90° phase shifted from the switching action. Given the
availability and quality of MLCCs and the expected output voltage of designs using the LMR10510, there is really
no need to review any other capacitor technologies. Another benefit of ceramic capacitors is their ability to
bypass high frequency noise. A certain amount of switching edge noise will couple through parasitic
capacitances in the inductor to the output. A ceramic capacitor will bypass this noise while a tantalum will not.
Since the output capacitor is one of the two external components that control the stability of the regulator control
loop, most applications will require a minimum of 22 μF of output capacitance. Capacitance often, but not always,
can be increased significantly with little detriment to the regulator stability. Like the input capacitor, recommended
multilayer ceramic capacitors are X7R or X5R types.
CATCH DIODE
The catch diode (D1) conducts during the switch off-time. A Schottky diode is recommended for its fast switching
times and low forward voltage drop. The catch diode should be chosen so that its current rating is greater than:
Copyright ? 2011–2013, Texas Instruments Incorporated
Product Folder Links: LMR10510
11
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相关代理商/技术参数 |
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|---|---|
| LMR10510YSDX | 制造商:TI 制造商全称:Texas Instruments 功能描述:SIMPLE SWITCHER?? 5.5Vin, 1A Step-Down Voltage Regulator in SOT-23 and LLP |
| LMR10510YSDX/NOPB | 功能描述:直流/直流开关调节器 SIMPLE SWITCHER 5.5 Vin,1A SD Vltg Reg RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| LMR10515 | 制造商:TI 制造商全称:Texas Instruments 功能描述:SIMPLE SWITCHER? 5.5Vin, 1.5A Step-Down Voltage Regulator in SOT-23 and LLP |
| LMR10515XMF | 制造商:Texas Instruments 功能描述:BUCK, 1.5A, 5.5VIN 制造商:Texas Instruments 功能描述:BUCK, 1.5A, 5.5VIN; Primary Input Voltage:5.5V; No. of Outputs:1; Output Voltage:4.5V; Output Current:1.5A; Voltage Regulator Case Style:SOT-23; No. of Pins:5; Operating Temperature Min:-40C; Operating Temperature Max:125C; SVHC:No;RoHS Compliant: Yes |
| LMR10515XMF/NOPB | 功能描述:直流/直流开关调节器 SIMPLE SWITCHER 5.5 Vin,1.5A SD Vltg Reg RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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