Knowles’ SPG08P4HM4H-1, a.k.a ‘Baracus’, is a multimode digital top port microphone from their SiSonic™ range of surface-mount MEMS microphones. The Baracus is a miniature, top port silicon microphone with a single-bit PDM output. The component consists of an acoustic sensor, a low-noise input buffer, and a sigma-delta modulator, and it was designed for use in a myriad of portable electronic devices where excellent wideband audio performance and RF immunity are required. With a low-frequency rolloff at 30 Hz and high-frequency flatness at 10 kHz (resonance peak at 20 kHz), the device should be capable of capturing a useful range of audible sound while rejecting rumble. Moreover, 64 dB Signal-to-Noise Ratio (SNR) and ±1 dB sensitivity matching greatly improves audio algorithm performance, including beam forming and noise suppression, and noise-immune duplex PDM output enables multi-mic architectures and eases system integration.
In addition to these audio specs, the Baracus offers multiple performance modes for minimising power consumption. With a Vdd of 1.65 V to 3.6 V, the typical supply current in normal mode is a mere 170 µA to 1250 µA (depending on the clock frequency), with 290 µA in low-power mode and 35 µA in sleep mode. The Baracus comes in a 4.0 x 2.0 x 1.1 mm package with 6 pads: data, ground, Vdd, clock, ground, and select.
Knowles makes a very large selection of microphones, so it makes sense that they decided to streamline evaluation with a universal evaluation kit and have the individual microphones available on flexible bias boards. The KAS-33100-0004, a.k.a. ‘Muskie’, microphone evaluation kit allows for simple-and-easy evaluation of Knowles SiSonic™ MEMS microphones. With it, engineers can evaluate two input channels of audio from multiple MEMS microphone types, whether these be single or differential analog MEMS microphones, digital PDM MEMS microphones like Baracus, or Digital I2S MEMS microphones. Clock frequencies are easily selectable during testing, as are voltages and gains, and multiple audio outputs – XLR, 3.5mm Headset Jack, USB Audio – allow for extremely flexible monitoring and data capture.
If you’re looking to evaluate a few different microphones for your application, feel free to specify them when applying for the Baracus and Muskie evaluation set. Knowles have just released a set of Automotive-qualified MEMS microphones that do not yet seem available for evaluation using the Muskie, but hopefully this will be the case soon, so do keep checking back. Active noise cancellation and low LFRO / Phase Distortion with background noise reduction and an enhanced dynamic range for better call quality sounds fantastic! Patience…
(Image sourced from Knowles)