7
4.3.2 Power ProgRock with 5V, and use the noise filter for 3.3V to Si5351A
Use this option if you want to power ProgRock with a 5V supply. In this case, leave off the 3.3V regulator
circuit from the Si5351A Synth PCB, as described in section 4.3.1. But do not install the voltage regulator
on the ProgRock PCB. Components R1, R2 and IC2 are not installed on the ProgRock PCB. These are
the components in the red rectangle below-left. The vacant LM317LZ should be jumpered as shown by the
pale blue line in the diagram below-right, so that the 5V supply reaches the rest of the ProgRock circuit.
4.3.3 Power ProgRock with 5V, and use the OCXO/Si5351A Synth kit
When using the OCXO/Si5351A Synth kit for very high frequency stability, you
should always power it with 5V because the oven heater circuit is designed to work
at 5V. In this case, build the OCXO/Si5351A kit exactly as described in its manual.
Omit R1, R2, C1 and IC2 from the ProgRock PCB. Jumper IC2, as described in the
above section 4.3.2. Also omit all the components associated with the noise filter
circuit, since the OCXO/Si5351A Synth kit has its own 3.3V regulators onboard,
which will supply its Si5351A chip.
Additionally, three jumper wires should be used feed the 5V supply to the
OCXO/Si5351A’s 5V supply pins. The three jumper wires are shown in blue (right),
and the pads on the PCB are laV1, +V2 and +V3.
4.3.4 Other supply options
There are other combinations of power regulator options that can be considered. For example you could
actually use the noise filter for the Si5351A power supply in the OCXO/Si5351A Synth kit, by modifying
that kit. Provision is made to jumper each of the three 5V pins to the OCXO/Si5351A Synth kit separately
so that if you wish, you can power them with separate 5V supplies (for absolutely the best frequency
stability this is a good idea).
All these options are advanced topics, to be attempted only by the experienced constructor after studying
and understanding all the circuit diagrams etc.
4.4
Assembly
The order of construction is not very important. However, a good principle to follow is to install the smaller
components first, so that the larger ones do not prevent easy access. One suggested order of construction
is described below. I recommend following it carefully.
