Saturday, 25 April 2015

Si5351 Shield Production PCBs

After a long gestation, the production version of the Kanga / m0xpd Si5351 Shield PCBs is now back from the delivery room...


I just finished populating the first full board and - like all proud fathers - I'm pretty pleased with it...


The board now uses the full Arduino 1.0 pin-out, so logic voltage level selection is automatic, being set by the host board through the "IOREF" pin.

Whilst this board is offered in the format of an Arduino shield, it calls upon very few of the resources of the Arduino and can run perfectly well within another computing framework. It has, for example, already been demonstrated with a Raspberry Pi and can be controlled by any system capable of generating the necessary I2C commands.

As has been explained in previous posts describing "engineering" versions of the shield, the "m0xpd RF Bus", first seen on the Kanga / m0xpd DDS Shield,  has been enhanced to support the three RF outputs of the Si5351, whilst retaining backwards compatibility with the original RF Bus. This allows the Kanga / m0xpd Tx shield and the new Rx shield to be used with this new RF generator.

In addition to quadrature square wave outputs derived from CLK2 (Q and I outputs were also provided on the DDS Shield) the new shield also presents the complements of these quadrature square waves on the RF bus to make it easier to drive certain implementations of "Tayloe" detectors.

The new shield  also includes two of Pete Juliano, n6qw's "Afterburner" amplifiers, which are seen on the annotated picture below...


The Si5351 alone only produces about 0.7 V into 50 Ohms. The addition of Pete's reheat livens things up nicely (to leave a diode in no doubt as to which way is up!)...

This - remember - is provided on two independent channels, derived from the Si5351's CLK0 and CLK1, and these amplified outputs are transformer isolated (see the binocular cores near the SMA sockets).

Kanga UK are planning to launch this new shield at the Four Days in May event in Dayton, Ohio where it will be supported by plenty of software application examples - including for my Parallel IF scheme.

Even if you don't get one of these shields, do yourself a favour and check out the Si5351 - you'll be glad you did,

...-.- de m0xpd


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