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  • 參數(shù)資料
    型號: MAX1674EUA
    廠商: MAXIM INTEGRATED PRODUCTS INC
    元件分類: 穩(wěn)壓器
    英文描述: High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters
    中文描述: 1.5 A SWITCHING REGULATOR, 500 kHz SWITCHING FREQ-MAX, PDSO8
    封裝: UMAX-8
    文件頁數(shù): 7/12頁
    文件大?。?/td> 160K
    代理商: MAX1674EUA
    Detailed Desc ription
    The MAX1674/MAX1675/MAX1676 compact, step-up
    DC-DC converters start up with voltages as low as 0.9V
    and operate with an input voltage down to 0.7V.
    Consuming only 16μA of quiescent current, these
    devices offer a built-in synchronous rectifier that
    reduces cost by eliminating the need for an external
    diode and improves overall efficiency by minimizing
    losses in the circuit (see Synchronous Rectificationsec-
    tion for details). The internal MOSFET resistance is typi-
    cally 0.3
    , which minimizes losses. The current limit of
    the MAX1674 and MAX1675 are 1A and 0.5A, respec-
    tively. The MAX1675’s lower current limit allows the use
    of a physically smaller inductor in space-sensitive
    applications. The MAX1676 features a circuit that elimi-
    nates noise due to inductor ringing. In addition, the
    MAX1676 offers a selectable current limit (0.5A or 1A)
    for design flexibility.
    PFM Control S c heme
    A unique minimum-off-time, current-limited, pulse-fre-
    quency-modulation (PFM) control scheme is a key fea-
    ture of the MAX1674/MAX1675/MAX1676. This scheme
    combines the high output power and efficiency of a
    pulse-width-modulation (PWM) device with the ultra-low
    quiescent current of a traditional PFM (Figure 1). There
    is no oscillator; a constant-peak-current limit in the
    switch allows the inductor current to vary between this
    peak limit and some lesser value. At light loads, the
    switching frequency is governed by a pair of one-shots
    that set a typical minimum off-time (1μs) and a typical
    maximum on-time (4μs). The switching frequency
    depends upon the load and the input voltage, and can
    range up to 500kHz. The peak current of the internal N-
    channel MOSFET power switch is fixed at 1A
    (MAX1674), at 0.5A (MAX1675), or is selectable
    (MAX1676). Unlike conventional pulse-skipping DC-DC
    converters (where ripple amplitude varies with input
    voltage), ripple in these devices does not exceed the
    product of the switch current limit and the filter-capaci-
    tor equivalent series resistance (ESR).
    S ync hronous Rec tific ation
    The internal synchronous rectifier eliminates the need
    for an external Schottky diode, thus reducing cost and
    board space. During the cycle off-time, the P-channel
    MOSFET turns on and shunts the MOSFET body diode.
    M
    High-Effic ienc y, Low-S upply-Current,
    Compac t, S tep-Up DC-DC Converters
    _______________________________________________________________________________________
    7
    MAX1674
    MAX1675
    MAX1676
    ONE-SHOT
    TRIG
    Q
    F/F
    R
    S
    Q
    ONE-SHOT
    TRIG
    Q
    CURRENT-LIMIT
    AMPLIFIER
    ERROR
    AMPLIFIER
    LOW-BATTERY
    COMPARATOR
    REFERENCE
    REF
    FB
    V
    IN
    47
    μ
    F
    47
    μ
    F
    R1
    200
    R5
    R6
    DAMPING
    SWITCH
    22
    μ
    H
    BATT
    (MAX1676)
    GND
    LX
    OUT
    0.1
    μ
    F
    0.1
    μ
    F
    V
    OUT
    R4
    LBI
    LBO
    R2
    100k
    R3
    V
    IN
    V
    OUT
    CLSEL
    (MAX1676)
    SHDN
    MINIMUM
    OFF-TIME
    ONE-SHOT
    ZERO
    CROSSING
    AMPLIFIER
    EN
    MAXIMUM
    ON-TIME
    ONE-SHOT
    P
    N
    Figure 1. Simplified Functional Diagram
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    相關(guān)代理商/技術(shù)參數(shù)
    參數(shù)描述
    MAX1674EUA+ 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
    MAX1674EUA+T 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
    MAX1674EUA-T 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
    MAX1674EUA-TG069 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
    MAX1675EUA 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT