Active mixer covers 450MHz to 3.6GHz cellular bands

31st January 2014

Nat Bowers

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Datasheet

Covering all 450MHz-3.6GHz cellular bands with a single part, the LTC5577 active downconverting mixer has been introduced by Linear. Offering outstanding +30dBm Input Third Order Intercept and 0dB conversion gain, the mixer's very low LO to RF leakage enable receivers to satisfy spurious emissions requirements with little or no RF input filtering.

The LTC5577 300MHz-6GHz active downconverting mixer is suited for cellular base station applications and a variety of radios requiring robust performance, such as cable TV transceivers, wideband military radios, broadband VHF/UHF white space broadcast radios, software-defined radios, RF test instrumentation, wireless repeaters and satellite communications.

Usable from 1MHz-1.5GHz, the LTC5577's IF output port provides flat conversion gain performance to over 600MHz bandwidth, supporting LTE and LTE-Advanced base stations and other wideband receiver applications. The exceptionally low M•RF x N•LO mixing spur products are suitable for low distortion receivers and improve the distortion correction performance of digital predistortion receivers. In order to ensure robust receiver sensitivity in the presence of interference, the LTC5577’s RF input is designed to withstand strong in-band blocking signals while delivering best-in-class (according to Linear) noise figure.

Integrated wideband RF and LO input transformers enable the LTC5577 to operate 50Ω single-ended from 700MHz-4.3GHz continuously with the same external matching. This results in minimal external component requirements, reduced system cost and reduced solution size. Whether the device is powered on or off, the LO input remains 50Ω terminated so that the mixer can be time division duplex enabled and disabled rapidly without causing disturbance that can unlock a phase-locked loop. Additionally, the LO input is buffered, requiring only 0dBm drive level. This allows it to be driven directly from a VCO circuit with minimum or no frequency pulling.

Operating over a temperature range from -40 to +105°C (making it suitable for reliable operation in harsh environments), the LTC5577 consumes the lowest power in the +30dBm IIP3 mixer class, powered by a single 3.3V supply at 180mA (a power consumption of just 594mW). The enable control pin allows for convenient shut down, and when disabled, the active mixer saves power by drawing a maximum leakage current of 200µA. With prices starting from $6.75 (USD) each in 1,000 unit quantities, the LTC5577 active downconverting mixer is available immediately in production quantities.