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Mirics MSi3101 Chipset – Heart of SDRPlay

mirics MSi3101 Chipset

The Mirics MSi3101 Chipset is the heart of SDRPlay RSP. It’s hard to believe that two chips the size of a fingernail produce such powerful radios. 

Similar to the heritage of various RTL-SDR devices, the Mirics MSi3101 Chipset was designed for ultra wideband broadcast receivers. First released as FlexiTV in 2010, Mirics entered the market for mainstream broadcast television and radio reception across all frequencies. This is a very large volume, tight margin business.

You will find that this product is comprised of two complex chips: the MSi001 wideband tuner and the MSi2500 analog digital converter. The MSi2500 also contains a USB interface, and uses the SPI bus to control the MSi001 tuner.

The tuner contains a programmable frequency synthesizer and down converter which produces I/Q data at baseband or low-IF. Its front end is a series of low noise amplifiers optimized for various frequency bands between 150 kHz and 1.7 GHz. Each LNA has noise and gain figures appropriate to the band. For example, for low frequencies, the NF is 6 dB and gain ranges from 40 to 100 dB.

The MSi2500 does analog to digital conversion and signal processing. The ADC is nominally 12 bit, effectively 10.4 bit. Both chips run off 3.3V and use little power. Engineers will find everything needed for a radio on this chipset except demodulation, which needs external software. In short, Mirics MSi3101 Chipset is an RF-to-USB solution.

If you are interested you can look at the MSi2500 and MSi001 datasheets. In addition to the RSP’s, the Mirics chipset is used in the Funcube+ dongle and recently in the CommRadio CR-1a receiver.

Mirics MSi3101 Chipset Synergy

Mirics and SDRPlay appear to have a close working relationship. Both are UK firms with a common registered office. Both share some common directors and shareholders.

I am guessing here, but I think that after the SDR amateur community began expressing interest in the Mirics MSi3101 chipset in 2013, some folks saw an incremental opportunity. Chipsets like these require huge investments. If you can broaden their use for secondary purposes, you can recoup some of your sunk costs. SDRPlay Limited was formed in 2014, shortly after Mirics released an SDR API. The first SDRPlay RSP came to market in the fall of 2014.

As described in Electronics Weekly: “SDRplay had the idea of partnering with Mirics to take their 12-bit wideband broadcast chipset and to re-purpose it for the hobbyist market.  The small company of engineers is spread around England and Wales and includes some ex-Mirics personnel as well as co-founder Jon Hudson.”

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