Wireless Systems Design

USB 1.1 Switch Offers Low Power And Bandwidth

Mobile wireless devices are popping up everywhere. Such devices rely on the high-speed broadband connectivity provided by Wi-Fi and cellular networks. In addition, these devices often need to communicate within a wireless personal-area network. But this demand places additional power requirements on the overall system. It also could potentially cause an increase in the device size. This increase would be unpopular with customers, who are constantly demanding devices that have smaller and smaller form factors.

To facilitate the move to ever-smaller ultra-portable devices, Fairchild Semiconductor has released a low-voltage analog switch. The FSUSB11 is a low-power, high-bandwidth, dual single-pole/double-throw (SPDT) USB switch. It achieves the fast-switch-time multiplexing/demultiplexing of analog audio and USB 1.1 signals.

This switch was designed specifically for USB applications. It is well suited to switching applications in ultra-portable cell phones; computers and peripherals; consumer electronics; and other USB 1.1-ported devices. The device provides the necessary performance through low power consumption, electrical-static-discharge (ESD) protection, and low total harmonic distortion (THD).

This high-performance, dual SPDT analog switch was specifically created for the switching of both analog audio and USB 1.1 signals. The device features ultra-low ON resistance of 1.3Ω maximum at 4.5 V (collector current voltage). At a 2.7-V supply voltage, it provides 4.3Ω ON resistance. The switch's high bandwidth and ultra-low ON resistance enable it to pass both USB low- and full-speed signals with minimum signal distortion. To achieve fast switching speeds, the device is fabricated with submicron CMOS technology. The select input is TTL-level compatible.

The FSUSB11 is housed in a 10-terminal, leadless MicroPak package. Because that package measures only 1.6 × 2.1 mm, it should optimize design flexibility in response to the growing miniaturization of portable equipment. Another key feature of the FSUSB11 USB analog switch is its high bandwidth of 350 MHz, which maintains signal fidelity. The switch flaunts ultra-low additive jitter of less than 2% UI typical.

The FSUSB11 is priced at $0.94 each in quantities of 1000. It is available now with a delivery time of four weeks ARO.

Fairchild Semiconductor Corp.
82 Running Hill Rd., South Portland, ME 04106; (207) 775-8100,

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