REV. B

SSM2166

–11–

Figure 13a. Evaluation Board Topside Silkscreen

(Not to Scale)

Figure 13b. Evaluation Board Topside

Metallization (Not to Scale)

Figure 13c. 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 12 and in

microphone applications, the phone jack shield can be option-

ally 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

configuration 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

operation. 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

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

Ω

resistance 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 output

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

an audio cable, then the on-board OP113 can be used. To use

the OP113 buffer, insert Jumper J4 into board socket pins

labeled “4” and “5” and insert Jumper J5 into board socket pins

labeled “6” and “7.” If the output buffer is not required,

remove Jumper J5 and insert Jumper J4 into board socket pins

“5” and “7.” There are no blocking capacitors either on the

input nor at the output of the buffer.