Scaled voltage reference with octave and semitone steps

Motivation

Quadrature LFO front view.

This module provides high precision CV outputs in 1V (octaves) and 83,3mV (halves) steps. The 1V output goes from -5 to +5V. The 83,3mV steps goes from -5 to plus 5 steps (halves). This module is thought for all who are missing octave switches in some modules. Especially in VCO. With this module you can switch octaves and halves as well.



Specs and features


Implementation

Schematic

Scaled voltage reference schematic

Scaled voltage reference schematic

Description:

The precision voltage is derived from the REF102. The negative voltage is provided with the INA105. It is crucial to match the resistors in the voltage dividers as good as you can. The outputs of the voltage dividers are buffered to avoid loading of the dividers. The resistors around the OpAmps must be matched as well. The one volt and the 83,3mV steps are added together with IC4A. The three outputs are individual buffered.


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Calibration

  • None
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Building hints

  • It is crucial to match the resistors in the voltage dividers as good as you can.

Special parts

  • None

Download

Scaled voltage reference documentation download
Scaled voltage reference Gerber files download

Scaled voltage reference front view

Scaled voltage reference: Front view


Scaled voltage reference populated PCB

Scaled voltage reference: Populated PCB


Scaled voltage reference back view

Scaled voltage reference: Back view


2020 February V 3.0.1

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