<b id="budxb"></b>
<u id="budxb"></u>
            
    
    
    參數(shù)資料
    型號(hào): SP3232H
    元件分類(lèi): RS-232
    英文描述: 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors
    中文描述: 5V的高速RS - 232收發(fā)器與0.1uF電容
    文件頁(yè)數(shù): 10/17頁(yè)
    文件大?。?/td> 147K
    代理商: SP3232H
    Rev. 6/27/03
    SP3222H/3232H 3.3V, 460 Kbps RS-232 Transceivers
    10
    Copyright 2003 Sipex Corporation
    Receivers
    The receivers convert EIA/TIA-232 levels to
    TTL or CMOS logic output levels. The SP3222H
    receivers have an inverting tri-state
    output.Receiver outputs (RxOUT) are tri-stated
    when the enable control EN = HIGH. In the
    shutdown mode, the receivers can be active or
    inactive. EN has no effect on TxOUT. The truth
    table logic of the
    SP3222H
    driver and receiver
    outputs can be found in
    Table 2
    .
    Since receiver input is usually from a transmis-
    sion line where long cable lengths and system
    interference can degrade the signal and inject
    noise, the inputs have a typical hysteresis margin
    of 300mV. Should an input be left unconnected,
    a 5k
    pulldown resistor to ground forces the
    output of the receiver HIGH.
    Charge Pump
    The
    Sipex
    patented charge pump (5,306,954)
    uses a four–phase voltage shifting technique to
    attain symmetrical 5.5V power supplies and
    requires four external capacitors. The internal
    power supply consists of a regulated dual charge
    pump that provides an output voltage of 5.5V
    regardless of the input voltage (V
    CC
    ) over the
    +3.0V to +5.5V range.
    In most circumstances, decoupling the power
    supply can be achieved adequately using a
    0.1
    μ
    F bypass capacitor at C5 (refer to
    Figures 6
    and
    7
    ). In applications that are sensitive to
    power-supply noise,V
    and ground can be
    decoupled with a capacitor of the same value
    as charge-pump capacitor C1. It is always
    important to physically locate bypass capacitors
    close to the IC.
    The charge pump operates in a discontinuous
    mode using an internal oscillator. If the output
    voltage is less than 5.5V, the charge pump is
    enabled. If the output voltage exceeds 5.5V,
    the charge pump is disabled. An oscillator
    controls the four phases of the voltage shifting.
    A description of each phase follows.
    Phase 1: V
    Charge Storage
    (Figure 12)
    During this phase of the clock cycle, the positive
    side of capacitors C
    and C
    are charged to V
    .
    C
    l
    C
    to V
    , the voltage potential across capacitor C
    2
    is now 2 times V
    CC
    .
    +
    is then switched to GND and the charge in
    is transferred to C
    . Since C
    +
    is connected
    Phase 2: V
    Transfer
    (Figure 13)
    Phase two of the clock connects the negative
    terminal of C
    to the V
    storage capacitor and
    the positive terminal of C
    to GND. This
    transfers a negative generated voltage to C
    3
    .
    This generated voltage is regulated to a
    minimum voltage of -5.5V. Simultaneous with
    the transfer of the voltage to C
    , the positive side
    of capacitor C
    is switched to V
    CC
    and the
    negative side is connected to GND.
    Phase 3: V
    Charge Storage
    (Figure 15)
    The third phase of the clock is identical to the
    first phase — the charge transferred in C
    1
    produces –V
    in the negative terminal of C
    1
    ,
    which is applied to the negative side of capacitor
    C
    . Since C
    across C
    2
    is 2 times V
    CC
    .
    +
    is at V
    CC
    , the voltage potential
    Table 2. Truth Table Logic for Shutdown and Enable
    Control
    N
    D
    H
    S
    N
    E
    T
    U
    O
    x
    T
    T
    U
    O
    x
    R
    0
    0
    e
    T
    e
    v
    A
    0
    1
    e
    T
    e
    T
    1
    0
    e
    v
    A
    e
    v
    A
    1
    1
    e
    v
    A
    e
    T
    相關(guān)PDF資料
    PDF描述
    SP3222HCA 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors
    SP3232HCA 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors
    SP3223EH High Speed Intelligent +3.0V to +5.5V RS-232 Transceivers(高速,智能+3.0V 至 +5.5V RS-232收發(fā)器(2發(fā)2收))
    SP3223EY 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors
    SP3223EUEP 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors
    相關(guān)代理商/技術(shù)參數(shù)
    參數(shù)描述
    SP3232HCA 制造商:SIPEX 制造商全稱(chēng):Sipex Corporation 功能描述:3.3V, 460 Kbps RS-232 Transceivers
    SP3232HCP 制造商:SIPEX 制造商全稱(chēng):Sipex Corporation 功能描述:3.3V, 460 Kbps RS-232 Transceivers
    SP3232HCT 制造商:SIPEX 制造商全稱(chēng):Sipex Corporation 功能描述:3.3V, 460 Kbps RS-232 Transceivers
    SP3232HCY 制造商:Exar Corporation 功能描述: 制造商:SIPEX 功能描述:
    SP3238 制造商:SIPEX 制造商全稱(chēng):Sipex Corporation 功能描述:Intelligent +3.0V to +5.5V RS-232 Transceiver