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參數(shù)資料
| 型號： | LM3671MF-1.875 |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 2MHz , 600mA Step-Down DC-DC Converter in SOT23-5 |
| 中文描述： | 1.15 A SWITCHING REGULATOR, 2600 kHz SWITCHING FREQ-MAX, PDSO5 |
| 封裝： | 2.92 X 2.84 MM, 1.20 MM HEIGHT, SOT-23, 5 PIN |
| 文件頁數(shù)： | 14/16頁 |
| 文件大小： | 967K |
| 代理商： | LM3671MF-1.875 |
Application Information
(Continued)
TABLE 1. Suggested Inductors and Their Suppliers
Model
Vendor
Coilcraft
Coilcraft
Panasonic
Sumida
Dimensions LxWxH(mm)
3.3 x 3.3 x 1.4
3.3 x 3.3 x 1.0
5.2 x 5.2 x 1.5
3.2 x 3.2 x 1.55
D.C.R (max)
200 m
150 m
53 m
94 m
DO3314-222MX
LPO3310-222MX
ELL5GM2R2N
CDRH2D14-2R2
OUTPUT CAPACITOR SELECTION
Use a 22 μF, 6.3V ceramic capacitor. Use X7R or X5R types,
do not use Y5V. DC bias characteristics of ceramic capaci-
tors must be considered when selecting case sizes like 0805
and 0603. DC bias characteristics vary from manufacturer to
manufacturer and dc bias curves should be requested from
them as part of the capacitor selection process. The LM3671
has been evaluated with 22 μF, 6.3V, 0805 with worst case
tolerances including dc bias effects. The use of two 10 μF,
6.3V, 0805 caps will give an overall higher capacitance value
when dc bias is considered.
The output filter capacitor smoothes out current flow from the
inductor to the load, helps maintain a steady output voltage
during transient load changes and reduces output voltage
ripple. These capacitors must be selected with sufficient
capacitance and sufficiently low ESR to perform these func-
tions.
The output voltage ripple is caused by the charging and
discharging of the output capacitor and also due to its R
ESR
and can be calculated as:
Voltage peak-to-peak ripple due to capacitance can be ex-
pressed as follows
Voltage peak-to-peak ripple due to ESR can be expressed
as follows
V
PP-ESR
= (2 * I
RIPPLE
)
*
R
ESR
Because these two components are out of phase the rms
value can be used to get an approximate value of peak-to-
peak ripple.
Voltage peak-to-peak ripple, root mean squared can be ex-
pressed as follows
Note that the output voltage ripple is dependent on the
inductor current ripple and the equivalent series resistance
of the output capacitor (R
ESR
).
The R
ESR
is frequency dependent (as well as temperature
dependent); make sure the value used for calculations is at
the switching frequency of the part.
TABLE 2. Suggested Capacitors and Their Suppliers
Model
Type
Vendor
Voltage Rating
Case Size
Inch (mm)
22 μF for C
OUT
GRM21BR60J226K
C2012X5R0J226K
JMK212BJ226K
10 μF for C
IN
GRM21BR60J106K
JMK212BJ106K
C2012X5R0J106K
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Murata
TDK
Taiyo-Yuden
6.3V
6.3V
6.3V
0805 (2012)
0805 (2012)
0805 (2012)
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Murata
Taiyo-Yuden
TDK
6.3V
6.3V
6.3V
0805 (2012)
0805 (2012)
0805 (2012)
BOARD LAYOUT CONSIDERATIONS
PC board layout is an important part of DC-DC converter
design. Poor board layout can disrupt the performance of a
DC-DC converter and surrounding circuitry by contributing to
EMI, ground bounce, and resistive voltage loss in the traces.
These can send erroneous signals to the DC-DC converter
IC, resulting in poor regulation or instability.
L
www.national.com
14
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LM3671MF-2.5 | 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 |
| LM3671MF-2.5/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 |
| LM3671MF-2.8 | 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 |
| LM3671MF-2.8/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 |
| LM3671MF-3.3 | 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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