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参数资料
| 型号： | LM2575IKTGR |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 稳压器 |
| 英文描述： | 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PSSO5 |
| 封装： | POWER FLEX, PLASTIC, 5 PIN |
| 文件页数： | 2/13页 |
| 文件大小： | 188K |
| 代理商： | LM2575IKTGR |
LM2575
1A SIMPLE STEPDOWN SWITCHING VOLTAGE REGULATOR
SLVS569A JANUARY 2005 REVISED FEBRUARY 2005
10
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
catch diode
As with other external components, the catch diode should be placed close to the output to minimize unwanted
noise. Schottky diodes have fast switching speeds and low forward voltage drops and, thus, offer the best
performance, especially for switching regulators with low output voltages (VOUT < 5 V). If a high-efficiency,
fast-recovery, or ultra-fast-recovery diode is used in place of a Schottky, it should have a soft recovery (versus
abrupt turn-off characteristics) to avoid the chance of causing instability and EMI. Standard 50-/60-Hz diodes,
such as the 1N4001 or 1N5400 series, are NOT suitable.
inductor
Proper inductor selection is key to the performance-switching power-supply designs. One important factor to
consider is whether the regulator will be used in continuous (inductor current flows continuously and never drops
to zero) or in discontinuous mode (inductor current goes to zero during the normal switching cycle). Each mode
has distinctively different operating characteristics and, therefore, can affect the regulator performance and
requirements. In many applications, the continuous mode is the preferred mode of operation, since it offers
greater output power with lower peak currents, and also can result in lower output ripple voltage. The
advantages of continuous mode of operation come at the expense of a larger inductor required to keep inductor
current continuous, especially at low output currents and/or high input voltages.
The LM2575 can operate in either continuous or discontinuous mode. With heavy load currents, the inductor
current flows continuously and the regulator operates in continuous mode. Under light load, the inductor fully
discharges and the regulator is forced into the discontinuous mode of operation. For light loads (approximately
200 mA or less), this discontinuous mode of operation is perfectly acceptable and may be desirable solely to
keep the inductor value and size small. Any buck regulator eventually will operate in discontinuous mode when
the load current is light enough.
The type of inductor chosen can have advantages and disadvantages. If high performance/quality is a concern,
then more-expensive toroid core inductors are the best choice, as the magnetic flux is contained completely
within the core, resulting in less EMI and noise in nearby sensitive circuits. Inexpensive bobbin core inductors,
however, generate more EMI as the open core will not confine the flux within the core. Multiple switching
regulators located in proximity to each other are particularly susceptible to mutual coupling of magnetic fluxes
from each other’s open cores. In these situations, closed magnetic structures (such as a toroid, pot core, or
E-core) are more appropriate.
Regardless of the type and value of inductor used, the inductor never should carry more than its rated current.
Doing so may cause the inductor to saturate, in which case the inductance quickly will drop and the inductor
will look like a low-value resistor (from the dc resistance of the windings). As a result, switching current will rise
dramatically (until limited by the current-by-current limiting feature of the LM2575) and can result in overheating
of the inductor and the IC itself. Note that different types of inductors have different saturation characteristics.
PRODUCT
PREVIEW
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2575IKTT | 制造商:TI 制造商全称:Texas Instruments 功能描述:1-A SIMPLE STEP DOWN SWITCHING VOLTAGE REGULATOR |
| LM2575IKTTR | 制造商:TI 制造商全称:Texas Instruments 功能描述:1-A SIMPLE STEP DOWN SWITCHING VOLTAGE REGULATOR |
| LM2575IN | 功能描述:直流/直流开关调节器 1A Simple Step-Down Switching Volt 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 |
| LM2575INE4 | 功能描述:直流/直流开关调节器 1A Simple Step-Down Switching Volt 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 |
| LM2575M-12 | 制造商:OC White Company 功能描述:Conv DC-DC Single Step Down 4V to 40V 24-Pin SOIC W |
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