In September of 2002 Maxim Integrated Products introduced (http://www.maxim-ic.com/view_press_release.cfm/release_id/686) the MAX2820 SiGe zero-IF transceiver, promoted as the industry's smallest RF transceiver designed specifically for 802.11b WLAN applications. Complete data sheets for the Max2820/Max2242 are available at: http://www.maxim-ic.com/arpdf/MAX2820-MAX2821.pdf
This single-chip design features a direct conversion (or zero-IF) architecture and integrated baseband filters for the receiver and transmitter. The device requires one ceramic RF bandpass filter compared to older superhet radio designs, which require at least three RF/IF chips, three RF bandpass filters, an IF SAW filter, as well as numerous other passive components. This reduction in component count can improve manufacturing yield, reliability, and cost. The Max2820/Max2242 can be used with the MAX2242 chip-scale power amplifier (PA), to provide an RF solution which occupies less than 300mm2 of board space. This type of design design may be helpful for compact flash, mini-PCI, and SD cards, or other small form factor WLAN applications.
The transceivers are designed for (11Mbps) applications operating in the 2.4GHz to 2.5GHz ISM band as per the IEEE 802.11b specifications . The MAX2821 provides low-power shutdown and analog voltage reference output features while the MAX2820 does not. Both include all the circuitry required to implement an 802.11b RF-to-baseband transceiver solution, and provide a fully integrated receive path, transmit path, VCO, frequency synthesis, and baseband/control interface. A PA, RF switch, RF BPF, and passive components are needed to form their radio front-end solution.
The transceivers have baseband filtering and RX and TX signal paths to support the CCK modulation scheme for BER = 10-5 at the required sensitivity levels.
The ZIF transceivers support the entire range of 802.11b data rates (1Mbps, 2Mbps, 5.5Mbps, and 11Mbps) as well as the higher-rate 22Mbps PBCC standard. The MAX2820/MAX2821 ZIF transceivers are available in 7mm x 7mm 48-lead QFN/thin QFN packages, respectively.
The supply range of the MAX2820 is 2.7V - 3.6V. Available in the 48-pin QFN leadless package measuring 7mm x 7mm, prices start at $9.95. Maxim also offers an evaluation kit, the MAX2820EVKIT , to assist in testing and developing with the MAX2820/MAX2821.