SSM2166

REV. A

–11–

Figure 23c. Evaluation Board Backside Metallization

(Not to Scale)

Signal sources are connected to the SSM2166 through a 1/8"

phone jack where a 0.1

µF capacitor couples the input signal to

the SSM2166’s +IN pin (Pin 7). As shown in Figure 22 and in

microphone applications, the phone jack shield can be optionally

connected to the board’s ground plane (Jumper J1 inserted into

board socket pins labeled “1” and “2”) or to the SSM2166’s

labeled “1” and “3”). If the signal source is a waveform or

function generator, the phone jack shield is to be connected

to ground.

For ease in making adjustments for all of the SSM2166’s con-

figuration parameters, single-turn potentiometers are used

throughout. Optional Jumper J2 connects the COMP RATIO

pin to ground and sets the SSM2166 for no compression (that

is, compression ratio = 1:1). Optional Jumper J3 connects the

SSM2166’s POWER DOWN input to ground for normal opera-

tion. Jumper J3 can be replaced by an open-drain logic buffer

for a digitally-controlled shutdown function. An output signal

MUTE function can be implemented on the SSM2166 by con-

necting the GAIN ADJUST pin (Pin 2) through a 330

Ω resis-

tance to ground. This is provided on the evaluation board via

R11 and S1. A capacitor C5, connected between Pin 2 and

ground and provided on the evaluation board, can be used to

avoid audible “clicks” when using the MUTE function.

To configure the SSM2166’s input buffer for gain, provisions for

R1, R2, and C2 have been included. To configure the input

buffer for unity-gain operation, R1 and R2 are removed, and a

direct connection is made between the –IN pin (Pin 6) and the

The output stage of the SSM2166 is capable of driving > 1 V

rms (3 V p-p) into > 5 k

Ω loads, and is externally available

through an RCA phono jack provided on the board. If the out-

put of the SSM2166 is required to drive a lower load resistance

Figure 23a. Evaluation Board Topside Silkscreen

(Not to Scale)

Figure 23b. Evaluation Board Topside Metallization

(Not to Scale)