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      參數(shù)資料
      

      


      


      
型號(hào)：
PIC16F639-I/SS

      

      
廠商：
Microchip Technology

      

      
文件頁數(shù)：
8/74頁

      

      
文件大?。?/td>
0K

      

      
描述：
IC MCU FLASH 2KX14 20SSOP

      

      
產(chǎn)品培訓(xùn)模塊：
Asynchronous Stimulus
      
	8-bit PIC® Microcontroller Portfolio
      		

      

      
標(biāo)準(zhǔn)包裝：
67

      

      
系列：
PIC® 16F

      

      
核心處理器：
PIC
      		

      

      
芯體尺寸：
8-位
      		

      

      
速度：
20MHz
      		

      

      
外圍設(shè)備：
欠壓檢測(cè)/復(fù)位，LVD，POR，WDT
      		

      

      
輸入/輸出數(shù)：
11
      		

      

      
程序存儲(chǔ)器容量：
3.5KB（2K x 14）
      		

      

      
程序存儲(chǔ)器類型：
閃存
      		

      

      
RAM 容量：
128 x 8
      		

      

      
電壓 - 電源 (Vcc/Vdd)：
2 V ~ 3.6 V
      		

      

      
振蕩器型：
內(nèi)部
      		

      

      
工作溫度：
-40°C ~ 85°C
      		

      

      
封裝/外殼：
20-SSOP（0.209"，5.30mm 寬）
      		

      

      
包裝：
管件
      		

      

      
產(chǎn)品目錄頁面：
638 (CN2011-ZH PDF)
      		

      

      
配用：
XLT20SS1-1-ND - SOCKET TRANSITION 20DIP 20SSOP
      XLT20SS-1-ND - SOCKET TRANSITION 18DIP 20SSOP
      AC162066-ND - HEADER INTRFC MPLAB ICD2 20PIN
      AC164307-ND - MODULE SKT FOR PM3 28SSOP
      		

      

      

      

	
      
    
    

    
      
	
      Micrel, Inc.
      KSZ8841-PMQL
      October 2007
      16
      M9999-100407-1.5
      Physical Layer Transceiver (PHY)
      100BASE-TX Transmit
      The 100BASE-TX transmit function performs parallel-to-serial conversion, 4B/5B coding, scrambling, NRZ-to-NRZI
      conversion, and MLT3 encoding and transmission.
      The circuitry starts with a parallel-to-serial conversion, which converts the 25MHz 4-bit nibbles into a 125MHz serial bit
      stream. The data and control stream is then converted into 4B/5B coding, followed by a scrambler. The serialized data
      is further converted from NRZ-to-NRZI format, and then transmitted in MLT3 current output. An external 1% 3.01K
      resistor for the 1:1 transformer ratio sets the output current.
      The output signal has a typical rise/fall time of 4ns and complies with the ANSI TP-PMD standard regarding amplitude
      balance, overshoot, and timing jitter. The wave-shaped 10BASE-T output driver is also incorporated into the 100BASE-
      TX driver.
      100BASE-TX Receive
      The 100BASE-TX receiver function performs adaptive equalization, DC restoration, MLT3-to-NRZI conversion, data
      and clock recovery, NRZI-to-NRZ conversion, de-scrambling, 4B/5B decoding, and serial-to-parallel conversion.
      The receiving side starts with the equalization filter to compensate for inter-symbol interference (ISI) over the twisted
      pair cable. Since the amplitude loss and phase distortion is a function of the cable length, the equalizer has to adjust its
      characteristics to optimize performance. In this design, the variable equalizer makes an initial estimation based on
      comparisons of incoming signal strength against some known cable characteristics, and then tunes itself for
      optimization. This is an ongoing process and self-adjusts against environmental changes such as temperature
      variations.
      Next, the equalized signal goes through a DC restoration and data conversion block. The DC restoration circuit is used
      to compensate for the effect of baseline wander and to improve the dynamic range. The differential data conversion
      circuit converts the MLT3 format back to NRZI. The slicing threshold is also adaptive.
      The clock recovery circuit extracts the 125MHz clock from the edges of the NRZI signal. This recovered clock is then
      used to convert the NRZI signal into the NRZ format. This signal is sent through the de-scrambler followed by the 4B/5B
      decoder. Finally, the NRZ serial data is converted to an MII format and provided as the input data to the MAC.
      PLL Clock Synthesizer (Recovery)
      The internal PLL clock synthesizer generates 125MHz, 62.5MHz, 41.66MHz, and 25MHz clocks by setting the on-chip
      bus speed control register OBCR for KSZ8841-PMQL system timing. These internal clocks are generated from an
      external 25MHz crystal or oscillator.
      Note: Default setting is 25MHz in OBCR register, recommends the software driver to set it to 125MHz for best
      performance.
      Scrambler/De-scrambler (100BASE-TX Only)
      The purpose of the scrambler is to spread the power spectrum of the signal to reduce electromagnetic interference
      (EMI) and baseline wander.
      Transmitted data is scrambled through the use of an 11-bit wide linear feedback shift register (LFSR). The scrambler
      generates a 2047-bit non-repetitive sequence. Then the receiver de-scrambles the incoming data stream using the
      same sequence as at the transmitter.
      10BASE-T Transmit
      The 10BASE-T driver is incorporated with the 100BASE-TX driver to allow for transmission using the same magnetic.
      They are internally wave-shaped and pre-emphasized into outputs with typical 2.4V amplitude. The harmonic contents
      are at least 27dB below the fundamental frequency when driven by an all-ones Manchester-encoded signal.
      10BASE-T Receive
      On the receive side, input buffers and level detecting squelch circuits are employed. A differential input receiver circuit
      and a phase-locked loop (PLL) perform the decoding function.
      The Manchester-encoded data stream is separated into clock signal and NRZ data. A squelch circuit rejects signals
      with levels less than 400mV or with short pulse widths to prevent noise at the RXP-or-RXM input from falsely triggering
      
    
      
    
    
      


      


      

      相關(guān)PDF資料
      		

      PDF描述
      		

      
      

      
PIC16F648A-I/ML
IC MCU FLASH 4KX14 EEPROM 28QFN

      

      
PIC16F676-I/ST
IC MCU FLASH 1K W/AD 14-TSSOP

      

      
PIC16F684-I/ST
IC PIC MCU FLASH 2KX14 14TSSOP

      

      
PIC16F688-I/ST
IC PIC MCU FLASH 4KX14 14TSSOP

      

      
PIC16F690-E/ML
IC PIC MCU FLASH 4KX14 20-QFN

      

      

      

      


      


      

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

      參數(shù)描述
      		

      
      

      
PIC16F639T-I/SO
功能描述:8位微控制器 -MCU 4kb 128 RAM 12 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT

      

      
PIC16F639T-I/SS
功能描述:8位微控制器 -MCU 4kb 128 RAM 12 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT

      

      
PIC16F648A-E/ML
功能描述:8位微控制器 -MCU 7KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT

      

      
PIC16F648A-E/P
功能描述:8位微控制器 -MCU 7KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT

      

      
PIC16F648A-E/SO
功能描述:8位微控制器 -MCU 7KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT

      

      
    
    
    
	
      	
    
    
     
     
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