<ul id="abxlx"></ul>
              


      
    



      

      
  
      
    
    
    
  
      
  
  

      





      


      
 
 




 
 


      

    
      


      參數(shù)資料
      

      


      


      
型號(hào)：
MAX799CPE

      

      
廠商：
MAXIM INTEGRATED PRODUCTS INC

      

      
元件分類：
穩(wěn)壓器

      

      
英文描述：
Octal D-type Transparent Latches With 3-State Outputs 20-CDIP -55 to 125

      

      
中文描述：
SWITCHING CONTROLLER, 330 kHz SWITCHING FREQ-MAX, PDIP16

      

      
封裝：
PLASTIC, DIP-16

      

      
文件頁(yè)數(shù)：
20/32頁(yè)

      

      
文件大?。?/td>
319K

      

      
代理商：
MAX799CPE


      

      

      

	
      
    
    

    
      
	
      M
      S tep-Down Controllers with 
      S ync hronous Rec tifier for CPU Power 
      20
      ______________________________________________________________________________________
      Three key inductor parameters must be specified:
      inductance value (L), peak current (I
      PEAK
      ), and DC
      resistance (R
      DC
      ). The following equation includes a
      constant LIR, which is the ratio of inductor peak-to-
      peak AC current to DC load current. A higher value of
      LIR allows smaller inductance, but results in higher
      losses and ripple. A good compromise between size
      and losses is found at a 30% ripple current to load cur-
      rent ratio (LIR = 0.3), which corresponds to a peak
      inductor current 1.15 times higher than the DC load
      current.
      V
      OUT
      (V
      IN(MAX)
      - V
      OUT
      )
      L = ———————————
      V
      IN(MAX)
      x f x I
      OUT
      x LIR
      f = switching frequency, normally 150kHz or 
      300kHz
      I
      OUT
      = maximum DC load current
      LIR = ratio of AC to DC inductor current, 
      typically 0.3
      The peak inductor current at full load is 1.15 x I
      OUT
       if
      the above equation is used; otherwise, the peak current
      can be calculated by:
      where:
      V
      (V
      - V
      )
      2 x f x L x V
      IN(MAX)
      I
      PEAK
       = I
      LOAD
      + ———————————
      The inductor’s DC resistance is a key parameter for effi-
      ciency performance and must be ruthlessly minimized,
      preferably to less than 25m
       at I
      OUT
       = 3A. If a stan-
      dard off-the-shelf inductor is not available, choose a
      core with an LI
      2
      rating greater than L x I
      PEAK2
      and wind
      it with the largest diameter wire that fits the winding
      area. For 300kHz applications, ferrite core material is
      strongly preferred; for 150kHz applications, Kool-mu
      (aluminum alloy) and even powdered iron can be
      acceptable. If light-load efficiency is unimportant (in
      desktop 5V-to-3V applications, for example) then low-
      permeability iron-powder cores, such as the
      Micrometals type found in Pulse Engineering’s 2.1μH
      PE-53680, may be acceptable even at 300kHz. For
      high-current applications, shielded core geometries
      (such as toroidal or pot core) help keep noise, EMI, and
      switching-waveform jitter low. 
      Current-S ense Resistor V alue
      The current-sense resistor value is calculated accord-
      ing to the worst-case-low current-limit threshold voltage
      (from the Electrical Characteristics table) and the peak
      inductor current. The continuous-mode peak inductor-
      current calculations that follow are also useful for sizing
      the switches and specifying the inductor-current satu-
      ration ratings. In order to simplify the calculation, I
      LOAD
      may be used in place of I
      PEAK
       if the inductor value has
      been set for LIR = 0.3 or less (high inductor values)
      and 300kHz operation is selected. Low-inductance
      resistors, such as surface-mount metal-film resistors,
      are preferred.
      80mV
      R
      SENSE
       =  ————
      I
      PEAK
      Input Capac itor V alue 
      Place a small ceramic capacitor (0.1μF) between V+
      and GND, close to the device. Also, connect a low-ESR
      bulk capacitor directly to the drain of the high-side
      MOSFET. Select the bulk input filter capacitor accord-
      ing to input ripple-current requirements and voltage rat-
      ing, rather than capacitor value. Electrolytic capacitors
      that have low enough ESR to meet the ripple-current
      requirement invariably have more than adequate
      capacitance values. Aluminum-electrolytic capacitors
      such as Sanyo OS-CON or Nichicon PL are preferred
      over tantalum types, which could cause power-up
      surge-current failure, especially when connecting to
      robust AC adapters or low-impedance batteries. RMS
      input ripple current is determined by the input voltage
      and load current, with the worst possible case occur-
      ring at V
      IN
      = 2 x V
      OUT
      :
      ————————
      √
      V
      OUT
      (V
      IN
      - V
      OUT
      )
      V
      IN
      I
      RMS
       =  I
      LOAD
       x  ——————————
      I
      RMS
       = I
      LOAD
      / 2 when V
      IN
      is 2 x V
      OUT
      Output Filter Capac itor V alue
      The output filter capacitor values are generally deter-
      mined by the ESR (effective series resistance) and volt-
      age rating requirements rather than actual capacitance
      requirements for loop stability. In other words, the low-
      ESR electrolytic capacitor that meets the ESR require-
      ment usually has more output capacitance than is
      required for AC stability. Use only specialized low-ESR
      capacitors intended for switching-regulator applications,
      such as AVX TPS, Sprague 595D, Sanyo OS-CON, or
      Nichicon PL series. To ensure stability, the capacitor
      must meet both minimum capacitance and maximum
      ESR values as given in the following equations: 
      V
      REF
      (1 + V
      OUT
      / V
      IN(MIN)
      )
      C
      F
       > ––––––––––––––––———–––
      V
      OUT
      x R
      SENSE
      x f
      R
      SENSE
      x V
      OUT
      V
      REF
      R
      ESR
       < ————————  
      (can be multiplied by 1.5, see note below)
      
    
      
    
    
      


      


      

      相關(guān)PDF資料
      		

      PDF描述
      		

      
      

      
MAX799CSE
Octal D-type Transparent Latches With 3-State Outputs 20-LCCC -55 to 125

      

      
MAX799EPE
Octal D-type Edge-Triggered Flip-Flops with 3-State Outputs 20-CDIP -55 to 125

      

      
MAX799ESE
Octal D-type Edge-Triggered Flip-Flops with 3-State Outputs 20-CDIP -55 to 125

      

      
MAX797HESE
High-Voltage, Step-Down Controller with Synchronous Rectifier for CPU Power

      

      
MAX799MJE
Step-Down Controllers with Synchronous Rectifier for CPU Power

      

      

      

      


      


      

      相關(guān)代理商/技術(shù)參數(shù)
      		

      參數(shù)描述
      		

      
      

      
MAX799CSE
功能描述:DC/DC 開(kāi)關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)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(fēng)格: 封裝 / 箱體:CPAK

      

      
MAX799CSE+
功能描述:DC/DC 開(kāi)關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)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(fēng)格: 封裝 / 箱體:CPAK

      

      
MAX799CSE+T
功能描述:DC/DC 開(kāi)關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)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(fēng)格: 封裝 / 箱體:CPAK

      

      
MAX799CSE-T
功能描述:DC/DC 開(kāi)關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)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(fēng)格: 封裝 / 箱體:CPAK

      

      
MAX799EPE
功能描述:DC/DC 開(kāi)關(guān)控制器

 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)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(fēng)格: 封裝 / 箱體:CPAK

      

      
    
    
    
	
      	
    
    
     
     
      發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。
      
 
     
      

   	  
      
     

      
                    			    				      
      
                
      
                  
      
                    
                    
      
                      
      
                      
                      
      采購(gòu)需求
        (若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)
      
                      
                      
      發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)
      
                      
                      
      發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)
      
                       
                        
      
                                
                                
      
                                    *型號(hào)
                                    *數(shù)量
                                    廠商
                                    批號(hào)
                                    封裝
                                  
      
                                      
                                
                                
      
                                    
                                        
      
                                            
                                            
                                        
      
                                          		
                                     
                                    
                                        
      
                                          		
                                    
                                        
      
                                          		
                                    
                                        
      
                                          		
                                    
                                        
      
                                          		
                                  
      
                                  
                                   
                                      
                            
      
                             
                             
							                            
      
                          添加更多采購(gòu)
      
                      
      
                      
                      
      
                      
                      
      我的聯(lián)系方式
      
                     
                     
                       
      
                                
                                
                                
      
                                    
                                         *
                                    
                                    
                                  
      
                                  
                                  
      
                                    
                                         *
                                    
                                    
                                  
      
                                  
                                  
      
                                    
                                        
                                    
                                    
                                  
      
                                  
                                  
      
                                    
                                         *