CMX655D – Ultra-low Power Voice Codec

Product description

Traditionally voice codes have interfaced to electret microphones and speakers providing A to D and D to A functions, using precision oversampling data converters. Recent advances in microphone design using MEMS techniques are now changing this, along with higher efficiency speaker driver architectures such as Class D topologies. Both of these advances enable significant reductions in power consumption which is needed to address new applications such as voice control, that require always-on operation. Such applications that are often battery powered, driving the need for ultra-low power consumption.

The CMX655D addresses these needs, providing an update to the traditional voice codec, that is both very low power and small in size. Microphone interfaces connect single or dual MEMS microphones to the device, with parallel processing of each data stream to maintain phase alignment between the two channels.

In the reverse channel, digital voice data drives a Class D speaker driver, also featuring programmable filtering and digital gain control. This architecture operates with much higher efficiency than conventional speaker drivers. An additional low level output is also provided.

The device interfaces via standard serial busses that are commonly found on many microcontrollers, DSPs and low cost single chip radio transceivers.

The CMX655D is available in a small VQFN-24 package and supported by a range of development tools, including the EV6550D evaluation kit.

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Devices are available through our distributors below:

Features

• Digital microphone MEMS support
• High efficiency Class-D speaker driver
• Low power consumption
• 16 bit audio data
• Supports conventional telephony and HD voice (300Hz – 3.4kHz and 50Hz – 7kHz bandwidths)
• Supports audio bandwidths up to 21kHz
• Supports 8/16/32/48 ksps sample rates
• Flexible serial audio interface
• SPI™/TWI control interface
• Small 24-lead VQFN Package
• 1.8 – 3.6V supply

Design resources