SSM2167-1RMZ-R2

Overview

The SSM2167-1RMZ-R2 is a low voltage microphone preamplifier with variable compression and noise gating manufactured by Analog Devices Inc. It operates on a single 3 V supply and features a shutdown current of less than 2 µA. The device provides an adjustable noise gate threshold, adjustable compression ratio, and an automatic limiting feature to prevent ADC overload. Audio specifications include 0.2% THD + N and a 20 kHz bandwidth. It is housed in a 10-lead MSOP package and guaranteed for operation over the extended industrial temperature range of −40°C to +85°C.

Feature Summary

• Complete microphone signal conditioning system integrating amplification, limiting, variable compression, and noise gate functions within a single integrated circuit.
• Features a low noise voltage controlled amplifier (VCA) that dynamically adjusts gain via a control loop to maintain a set compression characteristic.
• Includes a downward expander (noise gate) to prevent amplification of background noise or hum, optimizing signal levels prior to digitization.
• Provides an active low, CMOS-compatible digital power-down feature that significantly reduces device supply current for battery-powered applications.

Applications

• Desktop, portable, or palmtop computers
• Telephone conferencing systems
• Communication headsets
• Two-way communications equipment
• Surveillance systems

Procurement Notes

Verify the specific ordering suffix matches the required packaging format, such as REEL or R7, when sourcing the SSM2167-1RMZ variant. Confirm RoHS compliance status indicated by the Z suffix in the part number. Ensure the selected component meets the extended industrial temperature range requirements of −40°C to +85°C for your intended deployment environment.

Selection Notes

Select this component for voice-band applications requiring optimized signal levels before digitization without additional digital domain gain adjustments. Consider the fixed rotation point of 63 mV rms and the ability to vary compression ratios from 1:1 to over 10:1 using a single external resistor. Evaluate the need for the low shutdown current feature if the design relies heavily on battery power conservation.

Part Context

This component belongs to the SSM2167 family of audio signal processing integrated circuits designed by Analog Devices. It serves as a specialized solution for conditioning microphone inputs in personal electronics and computer audio systems. The device improves vocal clarity in communications and public address systems through its integrated dynamic range processing capabilities.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.

FAQ

How is the compression ratio configured?

The compression ratio is set by connecting a single external resistor (RCOMP) between Pin 8 and VDD. This allows the ratio to be varied from 1:1 to over 10:1 relative to the fixed rotation point.

What is the function of the SHUTDOWN pin?

Applying an active low, 0 V CMOS-compatible input to the SHUTDOWN pin (Pin 3) reduces the supply current to typically less than 2 µA. In this state, the input and output circuitry assume a high impedance state.

How does the device handle signals above the rotation point?

Signals above the rotation point are limited to prevent overload and eliminate popping. This automatic limiting feature prevents clipping of subsequent stages, such as codecs or ADCs.