SSM2166S Analog Devices Inc, SSM2166S Datasheet - Page 5

• Manufacturer Part Number: SSM2166S
• Description: IC PREAMP AUDIO MONO MIC 14SOIC
• Manufacturer: Analog Devices Inc

Specifications of SSM2166S

• Rohs Status: RoHS non-compliant
• Output Type: 1-Channel (Mono)
• Voltage - Supply: 4.5 V ~ 5.5 V
• Features: Microphone
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Max Output Power X Channels @ Load: -

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 4. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Mnemonic
GND
GAIN ADJUST
VCA
VCA
BUF OUT
−IN
AUDIO +IN
AVG CAP
NOISE GATE SET
COMP RATIO SET
ROTATION SET
POWER DOWN
OUTPUT
V+
IN
R
Description
Ground.
VCA Gain Adjust Pin. A resistor from this pin to ground sets the fixed gain of the VCA. To check the setting of
this pin, make sure the compression ratio set pin (Pin 10) is grounded for no compression. The gain can be
varied from 0 dB to 20 dB. For 20 dB, leave the pin open. For 0 dB of fixed gain, a typical resistor value is
approximately 1 kΩ. For 10 dB of fixed gain, the resistor value is approximately 2 kΩ to 3 kΩ. For resistor values
<1 kΩ, the VCA can attenuate or mute (see Figure 6).
VCA Input Pin. A typical connection is a 10 μF capacitor from the buffer output pin (Pin 5) to this pin.
Inverting Input to the VCA. This input can be used as a nonground reference for the audio input signal (see the
Applications Information section).
Input Buffer Amplifier Output Pin. This pin must not be loaded by capacitance to ground.
Inverting Input to the Buffer. A 10 kΩ feedback resistor, R1, from the buffer output (Pin 5) to this input pin and
a resistor, R2, from this pin through a 1 μF capacitor to ground give gains of 6 dB to 20 dB for R2 = 10 kΩ to 1.1 kΩ.
Input Audio Signal. The input signal should be ac-coupled (0.1 μF typical) into this pin.
Detector Averaging Capacitor. A capacitor, 1 μF to 22 μF, to ground from this pin is the averaging capacitor
for the detector circuit.
Noise Gate Threshold Set Point. A resistor to V+ sets the level below which input signals are downward
expanded. For a 0.7 mV threshold, the resistor value is approximately 380 kΩ. Increasing the resistor value
reduces the threshold (see Figure 5).
Compression Ratio Set Pin. A resistor to ground from this pin sets the compression ratio, as shown in Figure 2.
Figure 19 gives resistor values for various rotation points.
Rotation Point Set Pin. This pin is set by adding a resistor to the positive supply. This resistor together with
the gain adjust pin determines the onset of limiting. A typical value for this resistor is 17 kΩ for a 100 mV
rotation point. Increasing the resistor value reduces the level at which limiting occurs (see Figure 9).
Power-Down Pin. Connect this pin to ground for normal operation. Connect this pin to the positive supply
for power-down mode.
Output Signal.
Positive Supply, 5 V Nominal.
GAIN ADJUST
AUDIO +IN
BUF OUT
VCA
VCA
GND
–IN
IN
R
Figure 3. Pin Configuration
1
2
3
4
5
6
7
Rev. D | Page 5 of 20
(Not to Scale)
SSM2166
TOP VIEW
14
13
12
11
10
9
8
V+
OUTPUT
POWER DOWN
ROTATION SET
COMP RATIO SET
NOISE GATE SET
AVG CAP
SSM2166