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參數(shù)資料
| 型號： | LM3674MFX-2.8 |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | LM3674 2MHz, 600mA Step-Down DC-DC Converter in SOT 23-5; Package: SOT-23; No of Pins: 5; Qty per Container: 3000; Container: Reel |
| 中文描述： | 1.2 A SWITCHING REGULATOR, 2600 kHz SWITCHING FREQ-MAX, PDSO5 |
| 封裝： | SOT-23, 5 PIN |
| 文件頁數(shù)： | 4/15頁 |
| 文件大?。?/td> | 1102K |
| 代理商： | LM3674MFX-2.8 |
Application Information (Continued)
I
Ripple : average to peak inductor current
I
outmax: maximum load current (600mA)
V
IN: maximum input voltage in application
L: min inductor value including worst case tolerances
(30% drop can be considered for method 1)
f: minimum switching frequency (1.6 MHz)
V
OUT: output voltage
Method 2:
A more conservative and recommended approach is to
choose an inductor that has saturation current rating greater
than the max current limit of 1200 mA.
A 2.2 H inductor with a saturation current rating of at least
1200 mA is recommended for most applications. The induc-
tor’s resistance should be less than around 0.3
for good
efficiency. Table 2 lists suggested inductors and suppliers.
For low-cost applications, an unshielded bobbin inductor is
suggested. For noise critical applications, a toroidal or
shielded-bobbin inductor should be used. A good practice is
to lay out the board with overlapping footprints of both types
for design flexibility. This allows substitution of a low-noise
toroidal inductor, in the event that noise from low-cost bobbin
models is unacceptable.
INPUT CAPACITOR SELECTION
A ceramic input capacitor of 4.7 F, 6.3V is sufficient for most
applications. Place the input capacitor as close as possible
to the V
IN pin of the device. A larger value may be used for
improved input voltage filtering. Use X7R or X5R types; do
not use Y5V. DC bias characteristics of ceramic capacitors
must be considered when selecting case sizes like 0805 and
0603. The minimum input capacitance to guarantee
good performance is 2.2F at 3V dc bias; 1.5F at 5V dc
bias including tolerances and over ambient temperature
range. The input filter capacitor supplies current to the PFET
switch of the LM3674 in the first half of each cycle and
reduces voltage ripple imposed on the input power source. A
ceramic capacitor’s low ESR provides the best noise filtering
of the input voltage spikes due to this rapidly changing
current. Select a capacitor with sufficient ripple current rat-
ing. The input current ripple can be calculated as:
TABLE 2. Suggested Inductors and Their Suppliers
Model
Vendor
Dimensions LxWxH(mm)
D.C.R (max)
DO3314-222MX
Coilcraft
3.3 x 3.3 x 1.4
200 m
LPO3310-222MX
Coilcraft
3.3 x 3.3 x 1.0
150 m
ELL5GM2R2N
Panasonic
5.2 x 5.2 x 1.5
53 m
CDRH2D14NP-2R2NC
Sumida
3.2 x 3.2 x 1.55
94 m
LM3674
www.national.com
12
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LM3674MFX-ADJ | 功能描述:DC/DC 開關控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| LM3674MFX-ADJ/NOPB | 功能描述:DC/DC 開關控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| LM3676 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:2MHz, 600mA Step-Down DC-DC Converter with Mode Control |
| LM3676SD-1.5 | 功能描述:DC/DC 開關控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| LM3676SD-1.5/NOPB | 功能描述:DC/DC 開關控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
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