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I am trying to get an IC to generate a 100kHz sinusoidal waveform for my circuit. However when I google, all I can find are retired products which make me very hard to find (I stay in Singapore) so anyone know any active IC that can help me generate 100kHz signal? Thanks in advance.

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    \$\begingroup\$ Is there a microcontroller in the mix? If so, you might consider a DDS -- analog.com/en/rfif-components/direct-digital-synthesis-dds/… \$\endgroup\$ – Scott Seidman Feb 2 '15 at 20:15
  • \$\begingroup\$ DDS has replaced all the function generator IC's. You can make a triangle wave and then try to shape it. (There are some diode /transistor shaper circuits, none are very satisfying.) \$\endgroup\$ – George Herold Feb 2 '15 at 20:43
  • \$\begingroup\$ At 100kHz, a DDS is probably the way to go, even if you have to add a micro. \$\endgroup\$ – Spehro Pefhany Feb 2 '15 at 20:52
  • \$\begingroup\$ I have an arduino mega 2560 in the setup. But do I need any additional circuit/crystal besides the DDS? \$\endgroup\$ – WannaFly Feb 3 '15 at 17:24
  • \$\begingroup\$ And also, all of the ICs from Scott link has surface mount. Since I am going to solder it by hand, it will be great if I can find a DDS with through hole mount. \$\endgroup\$ – WannaFly Feb 3 '15 at 18:05
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The AD9850 is used in a few complete boards that are readily available from online auction sites. Datahseet to the chip: http://www.analog.com/media/en/technical-documentation/data-sheets/AD9850.pdf

Example of a complete module with passive filters to generate a Sine Wave: enter image description here

Failing that you could try making your own using a microcontroller generating a pwm according to a sine lookup table.

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Is this a fixed-frequency signal? If so, please Google the following terms:

  1. Wien bridge oscillator
  2. Twin t oscillator

I have built many Wien Bridge sine wave oscillators using a NE5534 (single) or NE5532 (dual) op-amps with a small "grain-of-wheat" light bulb for amplitude stabilization.

Note that the reason I chose those particular op-amps is that they have sufficient output current capability to drive the light bulb.

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    \$\begingroup\$ Dwayne, if you don't care too much about a little harmonic distortion (50-60 dB), then you might try this,dropbox.com/s/lmso5zx69g2l1lc/DSCF0047.JPG?dl=0 Diodes just clip off the tops of the sine waves. You can play with the gain resistors and get bigger signals and less distortion... up to the voltage limit of your power supply. \$\endgroup\$ – George Herold Feb 2 '15 at 20:46
  • \$\begingroup\$ Thank for your reply. However, as I am concerned with the size of the board, I prefer single IC with minimum amount of additional circuit. \$\endgroup\$ – WannaFly Feb 3 '15 at 18:06
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This might not be what you are looking for, but I generate waveforms of 100-250kHz using a simple 555 timer, logic gates to bring the signal fully high or low and either an RC or LC (this one works better but RC is easier) setup on the increase and decrease of the turn on/turn off and you will get very, very close to a sine wave. It won't be perfect though.

If it's AC you're looking for, the above minus the RC/LC and supplemented by a filtered H-bridge is how I do it.

There are probably better ways, I just use these cause I needed what you need a while back.

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