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Low-Cost, 900MHz, Low-Noise Amplifier and Downconverter Mixer

900MHz LNA and Mixer Offer Complete Front End Solution with only 8mA

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • 800MHz to 1000MHz RF Frequency Range
  • +2.7V to +5.5V Single-Supply Operation
  • Integrated LNA + Mixer + LO Buffer
  • Logic-Controlled LNA Bypass Switch Reduces Supply Current
  • LNA Performance (High/Low Gain)
    • Gain: +15dB/-12dB
    • NF: 1.4dB/12dB
    • Input IP3: -4dBm/+16dBm
  • Mixer Performance (High/Low Gain)
    • Gain: 6dB/4.6dB
    • NF: 13dB/12dB
    • Input IP3: +7dBm/-1.5dBm
  • Supply Current
    • 8.5mA (High Gain)
    • 3.8mA (Low Gain)
  • <0.1µA Supply Current in Shutdown Mode
  • 0.8µs Receiver Enable Time

Applications/Uses

  • 868MHz European ISM Band
  • 900MHz ISM-Band Applications
  • Cell Phones/Cordless Phones
  • Wireless Data

Description

The MAX2685's low-noise amplifier (LNA) and downconverter mixer comprise the major blocks of an RF front-end receiver. Optimized for 900MHz operation, the device's low noise figure, high gain, and high linearity make it ideal for cellular, cordless, and wireless data applications. A low supply current of 8.5mA (high-gain mode) and 3.8mA (low-gain mode) plus a low operating supply voltage range of +2.7V to +5.5V make it suitable for use in 3-cell NiCd or 1-cell lithium-ion (Li+) battery applications. A low-power shutdown mode further extends battery life by reducing supply current below 0.1µA.

The MAX2685 includes an LNA, LNA bypass switch, downconverter mixer, and local-oscillator (LO) buffer. The LNA has a low noise figure of 1.4dB, a high gain of 15dB, and an input third-order intercept point (IP3) of -4dBm. The mixer has a noise figure of 13dB, a gain of 6dB, and an input IP3 of +7dBm. In addition, an LNA bypass switch allows two levels of gain, reducing power consumption when high gain is not needed.

The downconverter mixer has a single-ended RF input port and differential IF output ports. Differential operation of the IF ports offers improved even-order harmonic rejection and increased immunity to noise. An LO buffer allows the LO port to be driven with only -8dBm of LO power. The MAX2685 is offered in a space-saving 16-pin QSOP package.

Simplified Block Diagram

MAX2685: Typical Operating Circuit MAX2685: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.