SSM2167-1RM-REEL ,Low Voltage Microphone Preamplifier with Variable Compression and Noise GatingSpecifications subject to change without notice.–2– REV. ASSM2167ABSOLUTE MAXIMUM RATINGS*Package T ..
SSM2167-1RMZ-R2 ,Low Voltage Microphone Preamplifier with Variable Compression & Noise GatingSpecifications subject to change without notice.–2– REV. BSSM2167ABSOLUTE MAXIMUM RATINGS*Package T ..
SSM2167-1RMZ-REEL ,Low Voltage Microphone Preamplifier with Variable Compression & Noise GatingGENERAL DESCRIPTIONLIMITINGLIMITINGREGIONThe SSM2167 is a complete and flexible solution for condit ..
SSM2167-1RMZ-REEL ,Low Voltage Microphone Preamplifier with Variable Compression & Noise GatingSPECIFICATIONSGATEParameter Symbol Conditions Min Typ Max UnitAUDIO SIGNAL PATHVoltage Noise Densit ..
SSM2210 ,Audio Dual Natched NPN transistorcharacteristics are guaranteed over the ex-
tended industrial temperature range of -4trC to +85°C. ..
SSM2210S ,Audio Dual Natched NPN transistorCHARACTERISTICS at Vcs = 15V, -4(y'C 5 T, 3 +85°C, unless otherwise noted.
SSM-2210
PARAMETER S ..
START405TR ,NPN SILICON RF TRANSISTORSTART405NPN Silicon RF Transistor• LOW NOISE FIGURE: NFmin = 1.1dB @ 1.8GHz, 2mA, 2V• COMPRESSION ..
START499ETR ,NPN Silicon RF TransistorAbsolute maximum ratings (T = +25°C) CSymbol Parameter Value UnitV Collector emitter voltage 4.5 V ..
STB0899 ,STB0899 databriefSTB0899Multistandard advance demodulator STB0899Digital TV satellite set-top boxesDATA BRIEFDESCRIP ..
STB0899 ,STB0899 databriefSTB0899Multistandard advance demodulator STB0899Digital TV satellite set-top boxesDATA BRIEFDESCRIP ..
STB0899/ ,STB0899 databriefSTB0899Multistandard advance demodulator STB0899Digital TV satellite set-top boxesDATA BRIEFDESCRIP ..
STB100NF03L-03 ,N-CHANNEL 30VELECTRICAL CHARACTERISTICS (T = 25 °C unless otherwise specified)caseOFFSymbol Parameter Test Condi ..
SSM2167-1RM-REEL
Low Voltage Microphone Preamplifier with Variable Compression and Noise Gating
REV.A
Low Voltage Microphone
Preamplifier with Variable
Compression and Noise Gating
FEATURES
Complete Microphone Conditioner in a 10-Lead Package
Single 3 V Operation
Low Shutdown Current < 2 �A
Adjustable Noise Gate Threshold
Adjustable Compression Ratio
Automatic Limiting Feature Prevents ADC Overload
Low Noise and Distortion: 0.2% THD + N
20 kHz Bandwidth
APPLICATIONS
Desktop, Portable, or Palmtop Computers
Telephone Conferencing
Communication Headsets
Two-Way Communications
Surveillance Systems
Karaoke and DJ Mixers
GENERAL DESCRIPTIONThe SSM2167 is a complete and flexible solution for conditioning
microphone inputs in personal electronics and computer audio
systems. It is also excellent for improving vocal clarity in communi-
cations and public address systems. A low noise voltage controlled
amplifier (VCA) provides a gain that is dynamically adjusted by a
control loop to maintain a set compression characteristic. The
compression ratio is set by a single resistor and can be varied from
1:1 to over 10:1 relative to the fixed rotation point. Signals above
the rotation point are limited to prevent overload and to eliminate
“popping.” A downward expander (noise gate) prevents amplifica-
tion of background noise or hum. This results in optimized signal
levels prior to digitization, thereby eliminating the need for addi-
tional gain or attenuation in the digital domain. The flexibility of
setting the compression ratio and the time constant of the level
detector, coupled with two values of rotation point, make the
SSM2167 easy to integrate in a wide variety of microphone
conditioning applications.
The SSM2167 is available in two versions, with different amounts
of fixed gain. The SSM2167-1 has 18 dB of fixed gain, while
the SSM2167-2 features only 8 dB of fixed gain.
The device is available in 10-lead MSOP package, and guaranteed
for operation over the extended industrial temperature range of
–40°C to +85°C.
PIN CONFIGURATION
10-Lead MSOP
(RM Suffix)Figure 1.General Input/Output Characteristics
SSM2167–SPECIFICATIONS
(@ VS = 3.0 V, f = 1 kHz, RL = 100 k�, RCOMP = 0 �, TA = 25�C, VIN = 100 mV rms,
RGATE = 2 k�, unless otherwise noted.)*Preliminary
Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS*Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 V
Operating Temperature Range . . . . . . . . . . .–40°C to +85°C
Junction Temperature Range . . . . . . . . . . . . . . . . . . . . 150°C
Lead Temperature Range (Soldering, 10 sec) . . . . . . . 300°C
ESD RATINGS883 (Human Body) Model . . . . . . . . . . . . . . . . . . . . . . 500 V
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational sections
of this specification is not implied. Exposure to absolute maximum rating condi-
tions for extended periods may affect device reliability.
*θJA is specified for worst-case conditions, i.e., θJA is specified for device soldered
in 4-layer circuit board for surface-mount packages.
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the SSM2167 features proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.
ORDERING GUIDE*Preliminary
SSM2167
– Typical Performance CharacteristicsTPC 1.Noise Gate vs. RGATE
TPC 2.THD + N vs. Frequency
TPC 3.GBW Curves vs. VCA Gain
TPC 4.THD + N vs. Input
TPC 5.Output vs. Input Characteristics
TPC 6.PSRR vs. Frequency
TPC 7.Small Signal Transient Response
TPC 8.Large Signal Transient Response
TPC 9.Small Signal Transient Response
TPC 10.Large Signal Transient Response
TPC 11.RMS Level Detector Performance with
CAVG = 22 µF
TPC 12.RMS Level Detector Performance with
CAVG = 2.2 µF
SSM2167
APPLICATIONS INFORMATIONThe SSM2167 is a complete microphone signal conditioning
system on a single integrated circuit. Designed primarily for
voice band applications, this integrated circuit provides amplifi-
cation, limiting, variable compression, and noise gate. User
adjustable compression ratio, noise gate threshold, and two
different fixed gains optimize circuit operation for a variety of
applications. The SSM2167 also features a low power shutdown
mode for battery-powered applications.
Figure 2.Typical Application Circuit
Theory of OperationThe typical transfer characteristic for the SSM2167 is shown in
Figure 1 where the output level in dB is plotted as a function of
the input level in dB. The dotted line indicates the transfer
characteristic for a unity-gain amplifier. For input signals in the
range of VDE (Downward Expansion) to VRP (Rotation Point)
an “r” dB change in the input level causes a 1 dB change in the
output level. Here, “r” is defined as the “compression ratio.”
The compression ratio may be varied from 1:1 (no compression)
to 10:1 via a single resistor, RCOMP. Input signals above VRP are
compressed with a fixed compression ratio of approximately
10:1. This region of operation is the “limiting region.” Varying
the compression ratio has no effect on the limiting region. The
breakpoint between the compression region and the limiting
region is referred to as the “limiting threshold” or the “rotation
point.” The term “rotation point” derives from the observation
that the straight line in the compression region “rotates” about
this point on the input/output characteristic as the compression
ratio is changed.
The gain of the system with an input signal level of VRP is the
“fixed gain,” 18 dBV for the SSM2167-1 and 8 dBV for the
SSM2167-2, regardless of the compression ratio.
Input signals below VDE are downward-expanded; that is, a –1 dB
change in the input signal level causes approximately a –3 dB
change in the output level. As a result, the gain of the system is
small for very small input signal levels, even though it may be
quite large for small input signals just above of VDE. The external
resistor at Pin 7, RGATE, is used to set the downward expansion
threshold VDE.
Finally, the SSM2167 provides an active low, CMOS-compatible
digital power-down feature that will reduce device supply current
to typically less than 2 �A.
SSM2167 Signal PathFigure 3 illustrates the block diagram of the SSM2167. The audio
input signal is processed by the input buffer and then by the VCA.
The input buffer presents an input impedance of approximately
100 kΩ to the source. A dc voltage of approximately 1.5 V is
present at INPUT (Pin 5 of the SSM2167), requiring the use of a
blocking capacitor (C1) for ground-referenced sources. A 0.1 µF
capacitor is a good choice for most audio applications. The input
buffer is a unity-gain stable amplifier that can drive the low imped-
ance input of the VCA and an internal rms detector.
The VCA is a low distortion, variable-gain amplifier whose gain
is set by the side-chain control circuitry. An external blocking
capacitor (C2) must be used between the buffer’s output and
the VCA input. The 1 kΩ impedance between amplifiers determines
the value of this capacitor, which is typically between 4.7 µF and
10 µF. An aluminum electrolytic capacitor is an economical choice.
The VCA amplifies the input signal current flowing through C2
and converts this current to a voltage at the SSM2167’s output pin
(Pin 9). The net gain from input to output can be as high as 40 dB
for the SSM2167-1 and 30 dB for the SSM2167-2, depending on
the gain set by the control circuitry.
The output impedance of the SSM2167 is typically less than 145 Ω,
and the external load on Pin 9 should be > 5 kΩ. The nominal
output dc voltage of the device is approximately 1.4 V, so a blocking
TPC 13.SSM2167-1 RMS Level Detector Performance
with CAVG = 2.2 µF
