The LT5557 from Linear Technology is a high-linearity, 3.3 V, downconverting active RF mixer. It elevates receiver dynamic range performance while extending bandwidth capability to cover 3G and WiMAX base station frequencies to 3.8 GHz.

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The LT5557 offers 24.7 dBm IIP3, a noise figure of 11.7 dB, and 2.9 dB of gain at 1.95 GHz. Its performance remains robust at WiMAX frequencies with 23.5 dBm IIP3, and 1.7 dB of gain at 3.6 GHz. This performance is achieved with a –3 dBm LO input drive level. Typical LO-to-RF isolation is better than 42 dBc at 1.95 GHz.

The LT5557's power consumption is low for this class of high-linearity mixers, typically 270 mW from a 3.3 V supply. The device incorporates on-chip RF transformers to enable single-ended, 50 Ω matching at the RF and LO inputs. The combination yields a receiver solution for wireless base stations of all types.

The LT5557 incorporates a double-balanced active mixer core topology with on-chip LO buffer. Differential drive is employed internally throughout the mixer to maximize linearity and RF isolation. Conversion from single ended to differential is accomplished through on-chip RF balun transformers at the RF and LO inputs. The device's operating bandwidth covers the 850 MHz to 965 MHz GSM and U.S. cellular bands, as well as 1.7 GHz to 2.1 GHz 3G wireless services. The LT5557 also supports WiMAX operating in the U.S. at 2.6 GHz and worldwide at up to 3.8 GHz.

The LT5557 operates from a single 3.3 V supply, drawing a quiescent supply current of 81.6 mA. When the chip is disabled, it draws a maximum sleep current of 100 mA. The device comes in a 16-lead 4 mm x 4 mm QFN surface-mount package. It is pin-compatible with Linear Technology downconverting mixers. Available now, pricing starts at $5.95 each in 1000-piece quantities.