Overview
The SSM2167-1RMZ-R7, produced by Analog Devices Inc., is a complete microphone signal conditioning system integrated into a single circuit. It is designed primarily for voice-band applications and is particularly useful in personal electronics and computer audio systems. This device offers a flexible solution for conditioning microphone inputs, enhancing vocal clarity in communications and public address systems.
Key Specifications
| Parameter | Symbol | Test Conditions/Comments | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| AUDIO SIGNAL PATH | ||||||
| Voltage Noise Density | en | 10:1 compression, 20 nV/√Hz | 20 nV/√Hz | nV/√Hz | ||
| Noise | 20 kHz bandwidth, VIN = GND | −70 dBV | dBV | |||
| Total Harmonic Distortion + Noise | THD + N | VIN = 100 mV rms | 0.2 % | % | ||
| Input Impedance | ZIN | 100 kΩ | kΩ | |||
| Output Impedance | ZOUT | 145 Ω | Ω | |||
| Load Drive Minimum resistive load | 5 kΩ | kΩ | ||||
| Maximum capacitive load | 2 nF | nF | ||||
| Input Voltage Range | 0.4% THD + N | 600 mV rms | mV rms | |||
| Output Voltage Range | 0.4% THD + N | 700 mV rms | mV rms | |||
| Gain Bandwidth Product | 1:1 compression, VCA G = 18 dB | 1 MHz | MHz | |||
| CONTROL SECTION | ||||||
| VCA Dynamic Gain Range | 40 dB | dB | ||||
| VCA Fixed Gain | 18 dB | dB | ||||
| Compression Ratio, Minimum | 1:1 | 1:1 | ||||
| Compression Ratio, Maximum | See Table 4 for RCOMP | 10:1 | ||||
| Rotation Point | 63 mV rms | 63 mV rms | mV rms | |||
| Noise Gate Range Maximum threshold | −40 dBV | −40 dBV | dBV | |||
| POWER SUPPLY | ||||||
| Supply Voltage | VSY | 2.5 V | 5.5 V | V | ||
| Supply Current | ISY | 2.3 mA | 5 mA | mA | ||
| DC Output Voltage | 1.4 V | V | ||||
| Power Supply Rejection Ratio | PSRR | VSY = 2.5 V to 6 V | 45 dB | dB | ||
| SHUTDOWN | ||||||
| Supply Current | ISY | Pin 3 = GND | 2 µA | 8 µA | µA |
Key Features
- Low Noise Voltage Controlled Amplifier (VCA): Provides dynamically adjusted gain to maintain a set compression characteristic.
- Variable Compression and Noise Gating: The compression ratio can be set from 1:1 to over 10:1, and a downward expander (noise gate) prevents amplification of background noise or hum.
- Wide Bandwidth: The upper 3 dB point is over 1 MHz at gains as high as 30 dB.
- Low Distortion: Total Harmonic Distortion + Noise (THD + N) is 0.2% at VIN = 100 mV rms.
- Flexible Input and Output: Input impedance of approximately 100 kΩ and output impedance of typically less than 145 Ω.
- Power Efficiency: Supply voltage range of 2.5 V to 5.5 V and low supply current.
- Digital Power-Down Feature: Reduces device supply current to typically less than 2 µA when in shutdown mode.
Applications
- Personal Electronics: Ideal for conditioning microphone inputs in smartphones, tablets, and other portable devices.
- Computer Audio Systems: Enhances audio quality in laptops, desktops, and other computer-based audio applications.
- Communications and Public Address Systems: Improves vocal clarity and reduces background noise in communication devices and public address systems.
Q & A
- What is the primary function of the SSM2167?
The SSM2167 is a complete microphone signal conditioning system designed primarily for voice-band applications. - What is the input impedance of the SSM2167?
The input impedance is approximately 100 kΩ. - What is the output impedance of the SSM2167?
The output impedance is typically less than 145 Ω. - What is the dynamic gain range of the VCA in the SSM2167?
The VCA dynamic gain range is 40 dB. - How is the compression ratio set in the SSM2167?
The compression ratio can be set from 1:1 to over 10:1 using a single resistor. - What is the purpose of the noise gate in the SSM2167?
The noise gate prevents amplification of background noise or hum. - What is the supply voltage range for the SSM2167?
The supply voltage range is 2.5 V to 5.5 V. - What is the typical supply current in shutdown mode?
The typical supply current in shutdown mode is less than 2 µA. - In what package is the SSM2167 available?
The SSM2167 is available in a 10-lead MSOP package. - What is the operating temperature range for the SSM2167?
The operating temperature range is −40°C to +85°C.
