View source for XR2206

[[File:XR2206_3D.png]]

== Features ==

The XR-2206 board is based on the XR-2206, which is a single IC function generator. The board adds the external parts to make a sine wave generator capable of being controlled from the High Voltage Digital Pot or the High Voltage Digital Pot 2 board. This allows a microcontroller to digitally set the frequency of the output.

=== XR-2206 IC ===

The XR-2206 can generate a low distortion sine wave well above and below the audio frequency range. The Exar XR-2206 is no longer manufactured, but it is widely available on ebay from China. 

The XR-2206 is a monolithic function generator integrated circuit capable of producing high quality sine, square, triangle, ramp, and pulse waveforms of high-stability and accuracy. The output waveforms can be both amplitude and frequency modulated by an external voltage. Frequency of operation can be selected externally over a range of 0.01Hz to more than 1MHz

== Rev X3 Board ==

* This is the third revision of the board
* Built onto the [[IntegTheremin]] board

=== Rev X3 Schematic ===

[[File:Xr2206-schematic-x3.PNG]]

=== Rev X3 Layout ===

[[File:Xr2206x3-front.png]]

=== Rev X3 Mounting Holes ===

The board has three 4-40 mounting holes for either mounting horizontally with standoffs or vertically with an L bracket.

=== Rev X3 improvements over X2 version ===

Replaced Waveform adjust fixed resistors with 25K variable resistor (RV1).
Split GVS header (J1) into GV and GS headers for separate power (J1) versus outputs (J3).
Added a 3rd mounting hole.

=== Connectors ===

The connectors are two pin 2.54mm (0.1") pitch headers.

==== J1 - Power ====

# +12VDC
# GND

==== J2 - Pot/Frequency Adjust ====

# GND
# Adjust

==== J3 - Output ====

# VCO Out
# GND

==== Rev X2 Board ====

[[File:XR-2206-2013-01-19-143626.jpg]]

== Rev X2 Schematic ==

[[File:Xr2206-schem-x2.PNG]]

=== Rev X2 Connectors ===

J1 is Power/signal control circuit connected as GVS (Ground, Voltage (+12V), and signal output).

# Ground
# Voltage (+12V)
# Sine wave output

J2 is the connection to an external pot.

$ Ground
# Resistance

=== Rev X2 Parts List ===

=== Rev X2 Mounting Holes ===

The board has a single 4-40 mounting hole for either mounting horizontally with standoffs or vertically with an L bracket.

=== Alternatives ===

DDS from an Arduino

== Rev X1 Board ==

[[File:XR-2206-2013-01-04-182208-X1.jpg]]

=== Rev X1 Schematic ===

[[File:Xr2206-schem-x1.PNG]]

=== Rev X1 Board Issues ===

* VGS silkscreen s/b GVS
* Resistors are 1/8W leaving this point alone since it's small and I bought 1/8W resistors already
* Dropped ground plane from .020 to .012"
* Need pin 3 connections.
* R1 s/b 10K
* Changed C1, was 1uF, s/b 0.1uF
* Pin 3 is missing waveform adjustment resistors