Xemics S.A., specializing in short-range wireless connectivity products announced the industry's lowest power CODEC for voice and audio applications: the XE3000 series. Besides its ultra low power consumption and low supply voltage, this product introduces a new function that detects if a voice or audio signal is processed in the CODEC. Without a voice signal, parts of the system can be put into sleep mode, thus the name, SANDMAN.

"The SANDMAN CODEC can be applied to all small battery-operated products where low power consumption and low supply voltage are key issues," said Sietse Wouters, Product Line Manager for the XE3000 series. " Our CODECs have by far the lowest power consumption in the industry (< 2 mW), and the lowest supply voltage (1.8V). Most CODECs available today consume around 50 mW and need a supply voltage of around 3 V".

The XE3000 series is ideally suited for application in Bluetooth and other types of wireless headsets or CD quality headphones. Other applications include handheld devices like GPS systems, PDAs, record and playback devices like MP3 players, and digital speakers. With a very small footprint (TSSOP), and direct connection to a microphone and speaker (no external amplifiers), the XE3000 series requires a minimum of low-cost external components (2 ceramic capacitors). Thus the overall system cost is lower than conventional solutions.

The XE3000 series consists of 4 different products: the XE3003 is an ADC (Analog to Digital Converter) and the XE3004 is a DAC (Digital to Analog Converter), both feature the Sandman function and are packaged in TSSOP20. The XE3005 is a CODEC (ADC + DAC) without Sandman function in TSSOP20 and the XE3006 is a CODEC with Sandman functions in TSSOP24.

This is not a high-fidelity stereo codec; it is a very practical well-specified codec for voice quality and its specifications make it ideal for portable devices using Bluetooth technology. The voice-/audio-operated automatic power up will be of enormous help in extending the battery life in such products. Additionally, the actual power consumption when either or both the ADC and DAC are in operation is extremely low.

While the part can operate down to 1.8 V the data sheet characterizations are with a 3.3-V supply. The analog input can be a directly-connected microphone, for which a 50 uA (max) bias supply is also provided, and a gain stage allows for x1 or x4 allowing the input signal to range from a maximum of 70 mV to 280 mV across 1 megohm. The output can also drive a loudspeaker or phones of at least 30 ohms with up to 100 mA. There are two digital interfaces: The serial audio interface carries the digital audio in both directions while the SPI configures the part. The ADC can be sampled from 4 to 20 kHz while the DAC can be sampled from 4 to 48 kHz. Only two external components are required, both are ceramic 1 uF capacitors to stabilize the reference voltage and the regulated voltage (which regulates the supply voltage to 1.6 V for internal operation.)