Audio Switches

Fairchild's audio switches offer various levels of On Resistance (as low as 0.35ohms), small scale packaging (as small as 1.45mm sqd) and are available in the most common switch configurations. All are designed to minimize THD, leakage current and crosstalk while maximizing ESD and Off Isolation.

The Low Icct switches allow the control pin(s) to have a lower voltage swing on its input, while minimizing power consumption. As a result, low Icct switches optimize battery life.

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Sample Application Diagrams


The FSA4157 is well suited for sharing single ended audio or other signals which require low On Resistance.


The FSA4157A includes our low Icct Circuitry which allows for direct interface with low voltage ASICS. (see App Note 5064)

Frequently Asked Question

1. What are the key parameters to consider when selecting an audio switch?

A. THD (total harmonic distortion) , On resistance, Ron flatness are the key features of Fairchild audio switches.

2. What is the difference between ‘A’ and ‘non-A’ audio switches?
A. The ‘A’ designator for the audio switches specifies the “Low-Icct” feature. This feature allows the control buffer input to be sourced by a lower Vcc GPIO with minimal impact in current consumption. This in turn extends battery life. (For additional information, please read applications note AN-5064.)

3. Can I switch a negative signal through my Audio switch?
A. Yes, Fairchild Semiconductor offers several audio switches with negative swing capabilities, the FSA2269TS,FSA2270TFSA2271TFSA2367, and the FSA2380.

4. Fairchild specifies a very high ESD rating on their audio switches, how are these values derived?
A. We test all switches to both the Human Body Model (HDM) and Charged Device Model (CDM) as outlined in the JEDEC standards JESD22- A114C-01 and JESD22-C101C respectively. Many switches also have specifications for Machine Model (MM). In addition, our ESD values specified are for contact rather than air discharge which also demonstrates a superior performance. Fairchild Semiconductor has leading edge technology to provide extremely robust ESD protection within our switches.  Many Fairchild Semiconductor switches have HBM contact ESD as high as 7-8kV contact.