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Amateur Radio Satellite Transceiver (SKY130) - Caravel Submission

This is the Google/EFabless/Skywater Caravel submission of the Amateur Radio Satellite Transceiver.


These blocks serve as the first pieces in a larger design of an open source amateur radio satellite transceiver - this is the first tapeout submission.

The design sources of the continued project can be found here: amsat_txrx_ic.

1.3 - 3.6 GHz Fractional-N Phase Locked Loop

pll VCO Layout

A S-Band phase locked loop employing a differential ring oscillator VCO with quadrature outputs. CML (Current Mode Logic) and flip-flop based pre-scaler dividers are used with a fractional-N divider which uses a 3rd order MASH structure with dithering. Finally a PFD (Phase Frequency Detector) is combined with a charge pump with off chip filtering to complete the loop.

A cell based buffer is used to drive the external 100 ohm differential output.


bandgap Bandgap Layout

A bandgap reference with separate PTAT and CTAT currents. Provides less than +/-0.2% variation from -40 to 125 degrees celcius (tt simulation). 6 bits of trimming on both PTAT and CTAT allows less than 1% accuracy over process variations.

Using the sources

To install the environment used for development of this repository, follow these instructions.

  1. Install the tools:

git clone https://github.com/yrrapt/sky130_setup.git cd sky130_setup ./install_pdk.sh ./install_tools.sh

  1. View schematics: cd amsat_txrx_ic-caravel/xschem xschem

  2. View layout: cd amsat_txrx_ic-caravel/gds klayout caravel.gds

  3. Run DRC: cd amsat_txrx_ic-caravel/utils ./run_drc amsat_txrx_ic-caravel

  4. Run LVS: cd amsat_txrx_ic-caravel/utils ./run_drc amsat_txrx_ic-caravel

If you are collaborating on this project, please click here to access your collaboration files, and click "Accept Share" in the actions column if you haven't done so already.

project layout image
project layout image
Layout Image
Thomas Parry
Organization URL



Amatuer Radio Satellite Transceiver (SKY130) - Caravel Submission