SiGe Transistors Minimize Cost

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Two new versions of the 5-GHz NPN silicon-germanium (SiGe) series of transistors are available from NEC. Best of all, they deliver the same low noise and low-current performance of gallium-arsenide (GaAs) at a greatly reduced cost. Both of these devices, the NESG2021 and the NESG2031, are ideal for use as LNA devices in wireless-local-area-network (WLAN), cordless-phone, and short-range wireless applications.

Because they're fabricated using NEC's silicon-germanium UHS2-HV (high-voltage) wafer process, the devices boast more design flexibility. They can use a wider and higher range of power-supply voltages.

The NESG2021 and NESG2031 are each housed in a miniature, low-profile, flat-lead M05 package. Based on the SOT-343 footprint, the M05 is just 0.59-mm high. It measures a mere 2.0 × 1.25 mm. Specific characteristics of the NESG2021 device include a noise figure and associated gain at 2 GHz of 0.9 dB and 18 dB, respectively. At 5.2 GHz, the noise figure is 1.3 dB, while the associated gain is 11 dB. It operates at 2 V with 3 mA. The maximum V_CEO of the NESG2021 is 5 V. The NESG2031 operates at 2 V and 5 mA, with a maximum V_CEO of 5 V.

At 2 GHz, the noise figure and associated gain are 0.8 and 17 dB. At 5.2 GHz, the noise figure and associated gain are 1.3 dB and 10 dB, respectively.

Design samples of both transistors are available from California Eastern Laboratories (CEL). Mass production has already begun. The NESG2021 is priced at 35¢, while the NESG2031 costs 37¢ in 100,000-unit quantities.