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参数资料
| 型号： | LM2575T-ADJ |
| 厂商： | MOTOROLA INC |
| 元件分类： | 稳压器 |
| 英文描述： | 3.2 A SWITCHING REGULATOR, 52 kHz SWITCHING FREQ-MAX, PSFM5 |
| 封装： | 314D-03 |
| 文件页数： | 3/28页 |
| 文件大小： | 380K |
| 代理商： | LM2575T-ADJ |
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LM2575
11
MOTOROLA ANALOG IC DEVICE DATA
Procedure (Adjustable Output Version: LM2575–Adj) (continued)
Procedure
Example
4. Inductor Selection (L1)
A. Use the following formula to calculate the inductor Volt x
microsecond [V x
s] constant:
B. Match the calculated E x T value with the corresponding
number on the vertical axis of the Inductor Value Selection
Guide shown in Figure 21. This E x T constant is a measure
of the energy handling capability of an inductor and is
dependent upon the type of core, the core area, the number
of turns, and the duty cycle.
C. Next step is to identify the inductance region intersected by
the E x T value and the maximum load current value on the
horizontal axis shown in Figure 21.
D. From the inductor code, identify the inductor value. Then
select an appropriate inductor from the Table 1 or Table 2.
The inductor chosen must be rated for a switching
frequency of 52 kHz and for a current rating of 1.15 x IIoad.
The inductor current rating can also be determined by
calculating the inductor peak current
:
where ton is the “on” time of the power switch and
For additional information about the inductor, see the
inductor section in the “External Components” section of
this data sheet.
ExT
+ V
in
–Vout
Vout
Von
x
106
F[Hz]
[V x
ms]
I
p(max)
+ I
Load(max) )
V
in
–Vout ton
2L
ton +
Vout
V
in
x
1
fosc
4. Inductor Selection (L1)
A. Calculate E x T [V x
s] constant:
B. E x T = 51 [V x
s]
C. ILoad(max) = 1.0 A
Inductance Region = L220
D. Proper inductor value = 220
H
Choose the inductor from the Table 1 or Table 2.
ExT
+ (12 – 8.0) x 8.0
12
x
1000
52
+ 51 [V x ms]
5. Output Capacitor Selection (Cout)
A. Since the LM2575 is a forward–mode switching regulator
with voltage mode control, its open loop 2–pole–2–zero
frequency characteristic has the dominant pole–pair
determined by the output capacitor and inductor values.
For stable operation, the capacitor must satisfy the
following requirement:
B. Capacitor values between 10
F and 2000 F will satisfy
the loop requirements for stable operation. To achieve an
acceptable output ripple voltage and transient response, the
output capacitor may need to be several times larger than
the above formula yields.
C. Due to the fact that the higher voltage electrolytic capacitors
generally have lower ESR (Equivalent Series Resistance)
numbers, the output capacitor’s voltage rating should be at
least 1.5 times greater than the output voltage. For a 5.0 V
regulator, a rating of at least 8V is appropriate, and a 10 V
or 16 V rating is recommended.
C
out w
7.785
V
in(max)
Vout xL [H]
[
F]
5. Output Capacitor Selection (Cout)
A.
To achieve an acceptable ripple voltage, select
Cout = 100 F electrolytic capacitor.
C
out w
7.785
12
8.220
+ 53 F
相关PDF资料 |
PDF描述 |
|---|---|
| LM2575T-5.0 | 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PSFM5 |
| LM2575D2T-3.3 | 3.2 A SWITCHING REGULATOR, 52 kHz SWITCHING FREQ-MAX, PSSO5 |
| LM2575TV-5.0 | 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PZFM5 |
| LM2575T-3.3 | 3.2 A SWITCHING REGULATOR, 52 kHz SWITCHING FREQ-MAX, PSFM5 |
| LM2575TV-ADJ | 3.2 A SWITCHING REGULATOR, 52 kHz SWITCHING FREQ-MAX, PZFM5 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2575T-ADJ | 制造商:Texas Instruments 功能描述:SWITCHING REG 1A ADJ 2575 TO2205 |
| LM2575T-ADJ/LB02 | 制造商:Texas Instruments 功能描述:SIMPLE SWITCHER 1A -40/+125 #01202511 |
| LM2575T-ADJ/LB03 | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM2575T-ADJ/LF02 | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM2575T-ADJ/LF03 | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
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