FUNCTIONAL BLOCK DIAGRAM

PIN CONNECTIONS

14-Pin Epoxy DIP

(P-Suffix)

16-Pin SOL

(S-Suffix)

REV. A

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a

Dual Audio

Analog Switches

SSM2402/SSM2412

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700

Fax: 617/326-8703

FEATURES

“Clickless” Bilateral Audio Switching

Guaranteed “Break-Before-Make” Switching

Low Distortion: 0.003% typ

Low Noise: 1 nV/

√Hz

Superb OFF-Isolation: 120 dB typ

Low ON-Resistance: 60

typ

18 V; 10 V rms

Wide Power Supply Range:

20 V max

Available in Dice Form

GENERAL DESCRIPTION

The SSM2402/SSM2412 are dual analog switches designed spe-

cifically for high performance audio applications. Distortion and

noise are negligible over the full audio operating range of 20 Hz to

20 kHz at signal levels of up to 10 V rms. The SSM2402/

SSM2412 offer a monolithic integrated alternative to expensive

and noisy relays or complex discrete JFET circuits. Unlike conven-

tional general-purpose CMOS switches, the SSM2402/SSM2412

provide superb fidelity without audio “clicks” during switching.

Conventional TTL or CMOS logic can be used to control the

switch state. No external pull-up resistors are needed. A “T”

configuration provides superb OFF-isolation and true bilateral

operation. The analog inputs and outputs are protected against

overload and overvoltage.

An important feature is the guaranteed “break-before-make”

for all units, even IC-to-IC. In large systems with multiple

switching channels, all separate switching units must open be-

fore any switch goes into the ON-state. With the SSM2402/

SSM2412, you can be certain that multiple circuits will all

break-before-make.

The SSM2402/SSM2412 represent a significant step forward in

audio switching technology. Distortion and switching noise are

significantly reduced in the new SSM2402/SSM2412 bipolar-

JFET switches relative to CMOS switching technology. Based

on a new circuit topology that optimizes audio performance,

the SSM2402/SSM2412 make use of a proprietary bipolar-

JFET process with thin-film resistor network capability. Nitride

capacitors, which are very area efficient, are used for the propri-

etary ramp generator that controls the switch resistance transi-

tion. Very wide bandwidth amplifiers control the gate-to-source

voltage over the full audio operating range for each switch. The

ON-resistance remains constant with changes in signal amplitude

and frequency, thus distortion is very low, less than 0.01% max.

The SSM2402 is the first analog switch truly optimized for

high-performance audio applications. For broadcasting and

other switching applications which require a faster switching

time, we recommend the SSM2412—a dual analog switch with

one-third of the switching time of the SSM2402.