The AS3435, for feedback systems, and AS3415, for feed-forward systems, incorporate ultra-low noise amplifiers with a 900 nV input referred noise floor: the devices are the first ANC speaker drivers to produce no audible high-frequency hiss when paired with low-noise microphones.
This means that manufacturers of audiophile products can replace existing ANC solutions with the AS3435 and AS3415 to provide users with an improved listening experience, benefiting from the devices’ audio characteristics including 35 mW stereo output power with THD+N of 0.1% into a 32Ω load and a typical signal-to-noise ratio of >110 dB.
These ANC ICs also provide for improvements to the mechanical design of a headset’s housing. Conventional ANC headsets require a mechanical switch, to activate a bypass mode. When the headset’s battery is completely discharged, the user must bypass the noise cancellation function in order to continue listening to music via the Line In channel. The need to accommodate this switch constrains the design of the headset’s housing and circuit board.
The AS3435 and AS3415 feature integrated bypass switches, so that the music signal coming from the 3.5 mm audio jack may be routed through the ANC chipset without any power source connected to the device. By eliminating the external switch, this feature helps to reduce bill-of-materials cost and the size of the PCB, as well as relieving the designer of the need to accommodate a mechanical switch on the headset’s housing.
At the same time, the devices’ analogue implementation of noise cancellation provides for power consumption often two or three times lower than equivalent digital solutions. Featuring typical power consumption of 10 mW at 1.5V in noise cancellation mode, either device can support operation for more than 100 hours from a single AAA battery.
ams has supported the introduction of the AS3435 and AS3415 ANC ICs with the release of an improved design tool, enabling development of the filter networks that match the operation of noise