SiGe mixer exhibits low noise, high linearity in wireless base stations
By Paul Rako, Technical Editor -- EDN, January 1, 2010
Maxim Integrated Product’s new MAX2042 upconverting and downconverting, double-balanced passive mixer operates at 2 to 3 GHz. The SiGe (silicon-germanium) chip includes an internal local-oscillator buffer and two baluns. It outputs an intermediate frequency of 50 to 500 MHz. Power consumption is 690 mW at 5V and 396 mW at 3.3V. Typical applications include LTE (long-term-evolution) and wireless base stations and WiMax (worldwide-interoperability-for-microwave-access), MMDS (multipoint-multichannel-distribution service) and WCS (wireless-communications service).
When operating as a downconverter the part has a minimum IP3 (third-order intercept point) of 34 dBm (decibels relative to 1 mW) when operating from 5V. At 3.3V, the typical IP3 is 31 dB. The single-sideband noise figure is 7.3 or 7.5 typical when operating from 5 and 3.3V, respectively. The device’s typical small-signal-conversion loss is 7.2 dB at a 3.3 or 5V supply voltage. The second RF harmonic minus the second harmonic of the local oscillator spur minimum rejection ranges of 54 dBc (decibels relative to the carrier) at 0-dBm output power and a 5V supply to typical rejection of 72 dBm at −10-dBm output power and a 3.3V supply.
When you operate the part as an upconverter, the MAX2042 delivers a minimum IIP3 of 30 dBm at 5V and 29.5 dBm typical at a 3.3V power-supply voltage. The typical small-signal-conversion loss is 6.8 dB for a 3.3 or 5V supply voltage. The unit achieves 67 dBc suppression of the local oscillator plus or minus the second harmonic of the intermediate frequency.
The MAX2042 operates at a −40 to +85°C junction temperature, comes in a 5×5-mm, 20-pin TQFN package, and sells for $ 5.95 (1000).
