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Maxim unveils transceivers for 802.11a, 802.11a/g apps

Posted: 06 Dec 2004 ?? ?Print Version ?Bookmark and Share

Keywords:maxim integrated products? rf transceiver? 802.11a? 802.11a/g? wlan?

Maxim Integrated Products released two single-chip RF transceivers designed for single-band 802.11a and dual-band 802.11a/g WLAN applications.

The new MAX2828 covers the world-band frequency spectrum from 4.9GHz to 5.9GHz, while the MAX2829 covers both 2.4GHz to 2.5GHz and 4.9GHz to 5.9GHz bands. These ICs feature a MIMO (Multiple-Input-Multiple-Output) mode in which the phase angle of the local oscillator is held constant during transmit/receive operation, allowing multiple transceivers to be synchronized to the system reference oscillator.

Manufactured using Maxim's in-house, high-performance SiGe BiCMOS process, these new transceivers, when compared to CMOS-only designs, provide as much as 4dB better receiver sensitivity performance in both 11a and 11g 54Mbps mode. This performance improvement translates to 58 percent longer range for line-of-sight WLAN applications and 36 percent longer range for indoor applications, Maxim said.

The transceivers derive their receiver sensitivity from a combination of an RF-optimized IC process technology and innovative circuit design, according to the press release. The result is a low receiver noise figure of 3.5dB, low oscillator phase noise of -99dBc/Hz at 100kHz, 35ns group-delay variation in the channel filter passband, and high-I/Q quadrature sideband suppression of 40dBc. In addition, a fast, digital AGC and DC-offset cancellation scheme allows antenna diversity selection within a packet header, further improvising range.

The new devices are designed with -10dBm receiver input IP3 at max gain, and 80dB filter channel selectivity, resulting in excellent immunity to 802.11a/g OFDM and 802.11b CCK jammers, the company said. On the transmitter side, the Tx output is highly linear, delivering -2.5dBm for 802.11g and -5dBm for 802.11a at <2 percent EVM. This allows the external PA to deliver its maximum power without added distortion from the transceiver, directly improving transmitter range.

The press release from Maxim further said that the transceivers significantly reduce the radio BoM cost and implementation size by integrating all RF transceiver function blocks between the RF switch and baseband processor I/Os. Not requiring any external SAW filter, the transceivers integrate the full transmit path (from baseband IQ input to RF output) and full receive path (from LNA input to baseband IQ output), a low-noise VCO, a fractional-N PLL synthesizer, and baseband/control interface. The devices operate from a 2.7V to 3.6V supply, and has a 1?A low-power shutdown mode that saves power during the system sleep mode.

The MAX2828 and MAX2829 are available in an 8-by-8mm, 56-pin, leadless QFN. Prices start at $7.11 (1,000-up, FOB USA). An evaluation kit is also available to help speed designs.

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