+14dBm to +20dBm LO Buffers with ±1dB Variation

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The MAX9989 and MAX9990 LO buffers provide the high output (+14dBm to +20dBm) necessary to drive the LO inputs of high-linearity passive mixers, while offering 40dB reverse isolation to prevent LO pulling. The MAX9989 is internally matched for the cellular/GSM bands, and the MAX9990 is matched for the DCS/PCS/UMTS bands.

The Typical Application Circuit provides a nominal +17dBm output power with ±1dB variation over supply, temperature, and input power. With two optional resistors, the output power can be precision set from +14dBm to +20dBm. The devices offer more than 35dB main driver output to PLL amp output isolation. Each device is offered in a 5mm x 5mm 20-pin thin QFN package with exposed paddle.
MAX9989, MAX9990: Typical Operating Circuit MAX9989, MAX9990: Typical Operating Circuit Enlarge+

Key Features

  • ±1dB Output Power Variation
  • +14dBm to +20dBm Adjustable Output Power
  • 40dB Reverse Isolation
  • Better Than 35dB Main Driver Output to PLL Amp Output Isolation
  • Low Output Noise: -170dBc/Hz at +17dBm
  • 110mA Supply Current at +17dBm
  • ESD Protection
  • Isolated PLL Output (+3dBm)
  • Applications/Uses

    • Cellular/GSM/DCS/PCS/UMTS Base Station Tx/Rx LO Drive
    • Coherent Receivers
    • ISM Wireless LAN
    • Local Multipoint Distribution Service
    • Point-to-Point Systems
    • Wireless Local Loop (WLL)

    See parametric specs for VCO Buffers/Splitters (7)

    Part NumberLO Driver OutputsPLL Driver OutputsRF Freq.
    RF Freq.
    (mm x mm)
    (min)(max)(min)(max)(See Notes)
    MAX9989 YesYes700110014.319.74.75 to 5.251055.0 x 5.0
    MAX9990 1500220014.219.5111
    $4.45 @1k

    Pricing Notes:
    This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
    Request Reliability Report for: MAX9989 
    Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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