The FSA557 integrates 0.3  depletion and enhancement mode
switches to provide a signal bypass solution when batteries of wireless
devices are low or have no charge left. In addition, an optional slow
gradual transition is included to suppress any undesirable artifacts (ex:
click and pop) when switching between signal sources. The depletion
technology allows the device to conduct signals when there is no VDD
available and to isolate signals when VDD is present. The FSA557 is
5.5 V tolerant and can pass or isolate negative signal swings down to −1.5 V.

Features
• Dual Depletion Switches
♦ Normally Closed when VDD < 0.5 V
♦ VSW: −1.5 V to +5.5 V
♦ RON: 220 m (Typical)
♦ THD+N: −110 dB (Typical)
• Dual Enhancement Switches
♦ VSW: −1.5 V to +5.5 V
♦ RON: 290 m (Typical)
♦ THD+N: −113 dB (Typical)

Typical Applications
• Battery Powered Devices
• Wireless Headphones