Post by thread:[EE]: Frequency Generator

I am using a PIC to make a frequency generator 0 to 50,000 Hz with 0.01% resolution. I have searched the PICLIST archives and the most suitable IC I have come across to do the frequency generation is the ML2036 from Fairchild semiconductor. Can anyone suggest anything else ? Maxim MAX038, Harris HSP45102, Motorola MC145162,Analog Devices AD9850 are too expensive and designed for RF so aren't really suitable. I have considered using a Direct Digital Synthesis (DDS) algorithm, but there is too much else going on in the processor to do this. Thanks in advance, James -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

James Hillman wrote: >I am using a PIC to make a frequency generator 0 to 50,000 Hz with 0.01% >resolution. I have searched the PICLIST archives and the most suitable IC I >have come across to do the frequency generation is the ML2036 from Fairchild >semiconductor. Can anyone suggest anything else ? > >Maxim MAX038, Harris HSP45102, Motorola MC145162,Analog Devices AD9850 are >too expensive and designed for RF so aren't really suitable. >I have considered using a Direct Digital Synthesis (DDS) algorithm, but >there is too much else going on in the processor to do this. > .01% = 1 part in 10,000. It may be difficult to get such fine frequency control unless you use DDS. However, another cheapo analog device to look at is the XR2206, readily available from jameco.com for ~3.00 USD. I have used it and prefer it over the 8038 chip, due to less waveform distortion. You can control it with PIC PWM fed to a BJT stage and get at least 1,000 different frequencies - although the control curve will be somewhat non-linear, smaller steps at low end, larger at high end. - dan michaels http://www.oricomtech.com ================== -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

James, it sounds like you've looked at the most popular chips. I've used the ML2036 as part of a PIC-based DAQ system. If you don't mind a 1Hz resolution, the ML2036 seems ideal. All you need is a crystal (literally, no capacitors). It requires +/- 5V and has a 3-wire SPI-style interface. You clock-in 16 Bits, LSB first, and set a Latch Enable line to set the frequency from 1 to 50KHz (I tested it to 65,535KHz). By using a 8.388608MHz crystal (Digi-Key PN: SE3415 / Epson CA-301 family), you get a direct one-to-one program data to frequency setting with a 1Hz resolution. The chip provides Osc/2 and Osc/8 outputs which may be of use if you want to clock a PIC at 4.194304MHz. There is a voltage reference input. Tying this to +5V gives a maximum output swing of +/- 2.5Vp-p. You can reduce this via an external reference. Harmonic distortion is -45db max. The device comes in a 14-pin DIP or 16-pin SOIC package. For more info: http://www.microlinear.com/ - Tom At 12:42 PM 2/22/01 -0000, James Hillman wrote: {Quote hidden}>I am using a PIC to make a frequency generator 0 to 50,000 Hz with 0.01% >resolution. I have searched the PICLIST archives and the most suitable IC I >have come across to do the frequency generation is the ML2036 from Fairchild >semiconductor. Can anyone suggest anything else ? > >Maxim MAX038, Harris HSP45102, Motorola MC145162,Analog Devices AD9850 are >too expensive and designed for RF so aren't really suitable. >I have considered using a Direct Digital Synthesis (DDS) algorithm, but >there is too much else going on in the processor to do this. > >Thanks in advance, > >James ------------------------------------------------------------------------ Tom Handley New Age Communications Since '75 before "New Age" and no one around here is waiting for UFOs ;-) -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Hello Tom, > James, it sounds like you've looked at the most popular chips. I've used > the ML2036 as part of a PIC-based DAQ system. If you don't mind a 1Hz > resolution, the ML2036 seems ideal. All you need is a crystal (literally, no <snip> > http://www.microlinear.com/ I've searched at MicroLinear site but can't find the ML2036. Can you tell me where do I find more informations? Thank you very much, Brusque ----------------------------------- Edson Brusque Research and Development C.I.Tronics Lighting Designers Ltda (47) 323-2685 / (47) 9993-6453 Blumenau - SC - Brazil http://www.citronics.com.br ----------------------------------- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> I've searched at MicroLinear site but can't find the ML2036. Can you >tell me where do I find more informations? >Thank you very much, >Brusque http://www.fairchildsemi.com/pf/ML/ML2036.html Thanks for the replies. I'm now looking at using an AD9832 with a 4MHz crystal. It has 2^32 resolution, but I don't know how accurate or stable it is (it only arrived this morning so testing not started yet). James -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads