App note: Analog switches solve many problems within a cell phone


Applications(PDF) of analog switches inside a cell phone by ON Semiconductor.

Analog switches have been available since the 60’s as a component for systems designers. With the advent of ASICs and ASSPs, many designers have not experienced the real value of these devices. Today’s designers may be familiar with the venerable MC14066, a workhorse that has been around for 30 years or more. The device consists of 4 independent switches that provide bilateral capabilities when “ON” and nearly infinite impedance when “OFF”.

Enter the single gate solution: On Semiconductor now offers a low voltage, single version of the 4066 in a one gate package. The MC74VHC1G66DFT2 is a single switch (SPST) occupying less than 4.5 mm 2 package, specified from 2.0-5.5 V and offers < 25 ohms resistance when turned “ON” and almost infinite impedance when turned off. Interestingly, the device can pass/stop either a digital or analog signal. Digital signals get passed with <1.0 ns delay, and very nearly no change in the signal. Analog signals get passed with less than 0.1% distortion and the device has a –3.0 dB point of >100 MHz. Several more devices were added to the portfolio including SPST, SPDT, dual SPST, DPDT, 2:1 Mux, dual DPDT functions. These are all available in tiny packages from 2.1 x 2.0 mm to 3.0 x 3.0 mm.

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