AS3400 AS3410 AS3430 Low Power Ambient Noise-Cancelling Speaker Driver Line Input 1 General Description Volume control via serial interface or volume pin The AS3400/10/30 are speaker driver with Ambient Noise Cancelling 64 steps 0.75dB and MUTE, pop-free gain setting function for handsets, headphones or ear pieces. It is intended to Single ended stereo or mono differential mode improve quality of e.g. music listening, a phone conversation etc. by reducing background ambient noise. ANC processing The fully analog implementation allows the lowest power Feed-forward cancellation consumption, lowest system BOM cost and most natural received voice enhancement otherwise difficult to achieve with DSP Feed-back cancellation with filter loop transfer function implementations. The device is designed to be easily applied to definable via simple RC components existing architectures. Simple in production SW calibration An internal OTP-ROM can be optionally used to store the 12-30dB noise reduction (headset dependent) microphones gain calibration settings. 10-2000Hz wide frequency active noise attenuation (headset The AS3400/10/30 can be used in different configurations for best dependent) trade-off of noise cancellation, required filtering functions and mechanical designs. Monitor Function The simpler feed-forward topology is used to effectively reduce low For assisted hearing, i.e. to monitor announcements frequency background noise. The feed-back topology with either 1 or Fixed (OTP prog.) ambient sound amplification to compensate 2 filtering stages can be used to reduce noise for a larger frequency headphone passive attenuation range, and to even implement transfer functions like speaker equalization, Baxandall equalization, high/low shelving filter and to Volume controlled ambient sound amplification mixed with fixed set a predefined loop bandwidth. (OTP prog.) attenuation of LineIn The filter loop is optimized by the user for specific handset electrical Incremental Functions and mechanical designs by dimensioning simple R, C components. ANC with or without music on the receiving path Most handset implementations will make use of a single noise detecting microphone. Two microphones could be used to allow for Improved dynamic range playback increased flexibility of their location in the handset mechanical OTP ROM for automatic trimming during production (4 times design. Using the bridged mode allows to even drive high impedance programbable) headsets. Performance Parameter 5/3.8mA 1.5V stereo/mono ANC <1A quiescent 2 Key Features Extended PSRR for 217Hz Microphone Input Interfaces 128 gain steps 0.375dB and MUTE with AGC 2-wire serial control mode & volume inputs Differential, low noise microphone amplifier Calibration via Line-In or 2-wire serial interface (patent pending) Single ended or differential mode Single cell or fixed 1.0-1.8V supply with internal CP Improved supply for electret microphone MIC gain OTP programmable Package AS3400, AS3410 QFN24 4x4mm 0.5mm pitch High Efficiency Headphone Amplifier AS3430 QFN32 5.x5mm 0.5mm pitch 2x34mW, 0.1% THD 16, 1.5V supply, 100dB SNR Bridged mode for e.g. 300 loads 3 Applications Click and pop less start-up and mode switching The devices are ideal for Ear pieces, Headsets, Hands-Free Kits, Mobile Phones, and Voice Communicating Devices. www.austriamicrosystems.com Revision 1.02 1 - 51AS3400 AS3410 AS3430 1v0 Data Sheet - Applications Figure 1. AS3410 Feed Forward ANC Block Diagram Figure 2. AS3430 Feed-Back Block Diagram www.austriamicrosystems.com Revision 1.02 2 - 51