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參數(shù)資料
| 型號： | L5985 |
| 廠商： | 意法半導體 |
| 英文描述： | 2A step-down switching regulator |
| 中文描述： | 第2A降壓型開關(guān)穩(wěn)壓器 |
| 文件頁數(shù)： | 15/36頁 |
| 文件大?。?/td> | 757K |
| 代理商： | L5985 |
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L5985
Application informations
15/36
5.2
Inductor selection
The inductance value fixes the current ripple flowing through the output capacitor. So the
minimum inductance value in order to have the expected current ripple has to be selected.
The rule to fix the current ripple value is to have a ripple at 20%-40% of the output current.
The inductance value can be calculated by the following equation:
Equation 6
Where T
ON
and T
OFF
are the on and off time of the internal power switch. The maximum
current ripple, at fixed Vout, is obtained at maximum T
OFF
that is at minimum duty cycle (see
previous section to calculate minimum duty). So fixing
I
L
=20% to 40% of the maximum
output current, the minimum inductance value can be calculated:
Equation 7
where F
SW
is the switching frequency 1/(T
ON
+ T
OFF
).
For example for V
OUT
= 3.3V, V
IN
= 12V, I
O
= 2A and F
SW
= 250KHz the minimum
inductance value to have
I
L
= 30% of I
O
is about 18uH.
The peak current through the inductor is given by:
Equation 8
So if the inductor value decreases, the peak current (that has to be lower than the current
limit of the device) increases. The higher is the inductor value, the higher is the average
output current that can be delivered, without reaching the current limit.
In the table below some inductor part numbers are listed.
Table 6.
Inductors
Manufacturer
Series
Inductor Value (
μ
H)
Saturation Current (A)
Wurth
TPC XLH
15 to 22
2.3 to 3.25
PD
3.3 to 6.8
2.5 to 2.75
Coilcraft
MSS1038
15 to 18
3.2 to 3.6
MSS7341
3.3 to 6.2
2.5 to 3.5
I
L
V
-----------–
T
ON
V
L
V
L
--------------
T
OFF
=
=
L
MIN
V
I
MAX
F
---------------+
1
---–
D
F
SW
=
I
L PK
I
O
I
L
2
-------
+
=
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| L5985TR | 2A step-down switching regulator |
| L5991 | PRIMARY CONTROLLER WITH STANDBY |
| L5991A | PRIMARY CONTROLLER WITH STANDBY |
| L5991AD | PRIMARY CONTROLLER WITH STANDBY |
| L5991D | PRIMARY CONTROLLER WITH STANDBY |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| L5985_08 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:2 A step-down switching regulator |
| L5985TR | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2a Step-Down Switching Reg RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| L5986 | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.5 A buck switching regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| L5986A | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.5 A STEP-DOWN SWITCH REG RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| L5986ATR | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 Step-down switch regulator, 2.5A RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
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