LMV1088 Datasheet | National Semiconductor

Description The LMV1088 is a fully analog dual input microphone array amplifier designed to reduce background acoustic noise, while delivering superb speech clarity in voice munications applications. The LMV1088 incorporates calibration circuitry which may be .. initiated by either an I2C mand or by a logic level control on a separate input pin. The calibration sequence pensates for gain and frequency response variations of the microphones used with the LMV1088, eliminating the need to use expensive matched microphone sets. The calibration data is stored in the internal EEPROM memory. The LMV1088 has two differential input microphone amplifier channels plus far field noise suppression (FFNS) processing circuitry. The amplifiers and FFNS circuitry are adjustable for gain differences in the MIC channels of +/- 3d B. The frequency response variations of the microphones over the voice band frequency range can also be adjusted for differences of +/-3d B. The pensation or calibration function is achieved via memory stored coefficients. These are determined when the FFNS calibration fuction is activated. The purpose of the calibration sequence is to choose the optimized coefficients for the FFNS circuitry for the given microphones, spacing, and acoustical environment. Key Specifications (3.3V supply, unless otherwise specified) - Supply voltage - Supply current - Signal to noise ratio (A-weighted) - Total harmonic distortion (A-weighted) - Temperature range 2.7V to 5.5V 1m A (typ) 60d B (typ) 0.1% (typ) - 40°C to 85°C Features - - - - - Low power consumption Neglectable noise suppression processing delay Automatic Calibration Three microphone usage modes Space-saving 36 Bump micro SMD package Applications - Cellular phones - Mobile and handheld two-way radios - Bluetooth and other powered headsets Application of the LMV1088 © 2007 National Semiconductor Corporation .national. Typical Application .. FIGURE 1. Typical Dual Microphone...