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參數(shù)資料
| 型號： | LM2733XMF |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.6/1.6 MHz Boost Converters With 40V Internal FET |
| 中文描述： | 1.5 A SWITCHING REGULATOR, 1850 kHz SWITCHING FREQ-MAX, PDSO5 |
| 封裝： | SOT-23, 5 PIN |
| 文件頁數(shù)： | 11/13頁 |
| 文件大?。?/td> | 507K |
| 代理商： | LM2733XMF |
Application Hints
(Continued)
MAXIMUM SWITCH CURRENT
The maximum FET swtch current available before the cur-
rent limiter cuts in is dependent on duty cycle of the appli-
cation. This is illustrated in the graphs below which show
both the typical and guaranteed values of switch current for
both the "X" and "Y" versions as a function of effective
(actual) duty cycle:
20055425
Switch Current Limit vs Duty Cycle - "X"
20055426
Switch Current Limit vs Duty Cycle - "Y"
CALCULATING LOAD CURRENT
As shown in the figure which depicts inductor current, the
load current is related to the average inductor current by the
relation:
I
LOAD
= I
IND
(AVG) x (1 - DC)
Where "DC" is the duty cycle of the application. The switch
current can be found by:
I
SW
= I
IND
(AVG) +
1
2
(I
RIPPLE
)
Inductor ripple current is dependent on inductance, duty
cycle, input voltage and frequency:
I
RIPPLE
= DC x (V
IN
-V
SW
) / (f x L)
combining all terms, we can develop an expression which
allows the maximum available load current to be calculated:
The equation shown to calculate maximum load current
takes into account the losses in the inductor or turn-OFF
switching losses of the FET and diode. For actual load
current in typical applications, we took bench data for vari-
ous input and output voltages for both the "X" and "Y"
versions of the LM2733 and displayed the maximum load
current available for a typical device in graph form:
20055434
Max. Load Current vs V
IN
- "X"
20055433
Max. Load Current vs V
IN
- "Y"
DESIGN PARAMETERS V
SW
AND I
SW
The value of the FET "ON" voltage (referred to as V
in the
equations) is dependent on load current. A good approxima-
tion can be obtained by multiplying the "ON Resistance" of
the FET times the average inductor current.
FET on resistance increases at V
values below 5V, since
the internal N-FET has less gate voltage in this input voltage
range (see Typical performance Characteristics curves).
Above V
IN
= 5V, the FET gate voltage is internally clamped
to 5V.
L
www.national.com
11
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| LM2734YMK | Thin SOT23 1A Load Step-Down DC-DC Regulator |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LM2733XMF/MEY8 | 制造商:Texas Instruments 功能描述: |
| LM2733XMF/NOPB | 功能描述:DC/DC 開關控制器 0.6/1.6MHZ BOOST CONVERTER 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 |
| LM2733XMFNOPB | 制造商:National Semiconductor 功能描述:Conv DC-DC Single Step Up 2.7V to 14V 5-Pin SOT-23 T/R |
| LM2733XMF-NOPB | 制造商:TI 制造商全稱:Texas Instruments 功能描述:LM2733 0.6/1.6 MHz Boost Converters With 40V Internal FET Switch in SOT-23 |
| LM2733XMFX | 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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