MMIC Mixers Reach High Intercept Points

These high-dynamic-range monolithic mixers set new standards in third-order-intercept-point performance for cellular and PCS infrastructure applications.

Dynamic range is a key requirement for the latest cellular and personal-communications-services (PCS) base stations. With growing complexity in digital modulation formats, and the use of dynamic power control, high-frequency mixers for these systems must deliver low noise and high third-order-intercept-point performance to meet even minimal dynamic-range requirements. Fortunately, the HMC399MS8, HMC400MS8, and HMC402MS8 monolithic-microwave-integrated-circuit (MMIC) mixers from Hittite Microwave (Chelmsford, MA) achieve third-order-intercept points (IP3s) to +36 dBm at cellular and PCS frequencies.

These passive gallium-arsenide field-effect-transistor (GaAs FET) MMIC mixers are ideal for Universal Mobile Telecommunications System (UMTS)-, code-division-multiple-access (CDMA)-, and Global System for Mobile Communications (GSM)-based systems. The low-cost mixers are supplied in plastic surface-mount eight-lead mini-small-outline-package (MSOP) housings and will satisfy a wide range of RF and intermediate-frequency (IF) plans for frequency upconversion or downconversion. At just 15 mm2, the footprint of these new MSOP mixers is one-tenth the size of a typical hybrid mixer J-lead package footprint of 152 mm2. The high input IP3 performance and output power at 1-dB compression rivals performance of traditional hybrid active FET mixers for an equivalent +17-dBm LO drive while requiring no DC bias supply.

Model HMC399MS8 operates over an RF range of 740 to 960 MHz, local-oscillator (LO) range of 540 to 900 MHz, and IF range of 60 to 250 MHz for GSM and CDMA applications. It provides IP3 performance to +35 dBm for downconversion and +32 dBm for upconversion. The mixer achieves as much as +23 dBm at 1-dB compression with 8.5-dB typical conversion loss and as much as 23 dB LO-to-RF isolation and 27 dB typical LO-to-IF isolation (see table). The single-sideband (SSB) noise figure is typically 9 dB over an RF range of 740 to 800 MHz, typically 8.5 dB for an RF range of 800 to 900 MHz, and typically 8 dB for an RF range of 880 to 960 MHz. The mixer requires only an external inductor and capacitor to optimize the LO frequency response.

Model HMC400MS8 covers an RF range of 1.7 to 2.2 GHz, LO range of 1.4 to 2.15 GHz, and IF range 50 to 300 MHz; it is suitable for most UMTS/PCS transmit or receive frequency plans configured with low-side LO architectures. This mixer offers excellent input IP3 performance to +36 dBm for downconversion to +31 dBm for upconversion. Rated for 1-dB compression of +21 dBm, the RF port can handle a wide range of input signal levels. The typical conversion loss is 8.8 dB while the typical LO-to-RF isolation is 33 dB and the typical LO-to-IF isolation is 23 dB. The typical SSB noise figure ranges from 8 to 9 dB across the full frequency range. No external components or bias are required with the HMC400MS8.

Finally, model HMC402MS8 covers an RF range of 1.8 to 2.2 GHz, an LO range of 1.85 to 2.53 GHz, and an IF range of 50 to 500 MHz, satisfying many UMTS/PCS transmit or receive frequency plans using a high-side LO configuration. The mixer features solid IP3 performance to +31 dBm for downconversion and to +27 dBm for upconversion. The 1-dB compression point is +21 dBm and the typical conversion loss is 8.5 dB. The typical SSB noise figure ranges from 8.5 to 8.8 dB across the full 1800-to-2200-MHz RF range. The HMC402MS8 exhibits 30 dB typical LO-to-RF isolation and 24 dB typical LO-to-IF isolation. As with the lower-frequency mixers, the HMC402MS8 does not require external components or a bias supply. All three mixers are 100-percent RF tested; all three are designed for nominal LO drive levels of +16 to +18 dBm. P&A: stock. Hittite Microwave Corp., 12 Elizabeth Dr., Chelmsford, MA 01842; (978) 250-3343, FAX: (978) 250-3373, Internet:

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