Wi-Fi Chip Brings MIMO To Mobile Devices

Marvell’s Avastar 88W8797

Marvell’s Avastar 88W8797 802.11n 2x2 multiple-input, multiple-output (MIMO) dual-band (2.4 and 5 GHz) system-on-a-chip (SoC) is designed for new tablet computers, as well as some smart phones and other devices that need extra fast wireless data downloads (see the figure). This chip’s 802.11n support for antenna beamforming can greatly extend range and link reliability. The chip also includes Bluetooth 4.0, the low-energy version that lets Bluetooth operate for about a year on a coin cell. But that’s not all. The 88W8797 sports an embedded FM radio receiver and transmitter. Also, the chip permits the use of the Wi-Fi Alliance’s DirectConnect feature, which lets two DirectConnect radios talk directly to one another without going through an access point. In addition to these features, the chip is an energy miser, making it a good fit for new mobile designs. The 88W8797 is especially suitable for new tablets. Its 2x2 MIMO ability gives designers flexibility in antenna placement, which is critical to good tablet performance. Single-stream Wi-Fi radios with one antenna can be compromised due to interference when the user is holding the tablet. With two antennas, the potential for interference is reduced and gives the tablet a better connection. When both antennas are working at their peak, data rates of up to 300 Mbits/s are possible—just what you need for video and games. While the Avastar is directed to new tablet and smart-phone designs, it is also a good choice for home media servers, set-top boxes, and digital TVs. The devices are sampling now.