Building a circuit which involves with a AD9854 DDS

In summary, the conversation revolves around the use of an AD9854 DDS chip for generating a frequency controllable sine wave. The main concern is finding a suitable crystal oscillator or CMOS programmable oscillator that can provide a 200MHz master clock supply for the chip. The correct link for the datasheet of the chip is provided and it is mentioned that the internal clock can run as low as 15MHz. The conversation also includes personal experiences and background information of the individuals involved.
  • #1
kent
13
0
Hi Guys..

I am try building a circuit which involves with a AD9854 DDS(Direct Digital Synthesis) chip to generate a frequency controlable sine wave for me...

The problem for me is that the Master clock supply for the chip need to be around 200MHz...I don't know whether there is any crystal oscillator that can perform this function...or maybe there are some CMOS programmable oscillator chips that can do the trick for me...?

Here is the link of the chip:
http://www.analog.com/en/prod/0,2877,AD9854,00.html

Thank you guys for ur help!
 
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  • #2
Sorry guys...wrong link...

Here is the correct one:
http://www.analog.com/en/prod/0,,770_843_AD9854,00.html
 
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  • #3
kent said:
Sorry guys...wrong link...

Here is the correct one:
http://www.analog.com/en/prod/0,,770_843_AD9854,00.html

On page 30 of that datasheet, it says that you can put in as little as 15MHz, which is definitely available in canned oscillator form. I'd stay away from messing around with anything over about 50MHz, unless you are making your own PCBs and understand stripline transmission line techniques.
 
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  • #4
kent said:
The problem for me is that the Master clock supply for the chip need to be around 200MHz...

HAHA! I made a lot of the plots that are in this datasheet when I was a co-op at Analog Devices ~10 years ago!

The internal clock on the AD9854 needs to be at least 20Mhz. There's a built in PLL multiplier, so the external clock source that you supply can be as low as 5Mhz. You just have to enable the multiplier, and set the bits appropriately (see pages 30-31).

On page 30 of that datasheet, it says that you can put in as little as 15MHz
as low as 15Mhz and still achieve 300Mhz internal clock. The internal clock can run lower than this as well.
 
  • #5
Thanks asynchronous13, and welcome to the PF. It must have been way cool to work at AD as a co-op! Where are you now?
 
  • #6
i ran 100's of these parts through FFT's for characterization while i was there. Analog Devices was a great place to work, but they didn't give me enough to do as a co-op, so i ended doing stuff like designing/building guitar distortion pedals for personal use :-)

10 yrs in summary: BS in EE from U of Tennessee -> Harris Corporation in FL (worked on international space station and Comanche helicopter) -> France for grad school, got a french EE degree -> masters in EE from GaTech (DSP) -> currently in Atlanta at GaTech working on PhD in unmanned aerial vehicles
 
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What is a AD9854 DDS?

The AD9854 is a direct digital synthesizer (DDS) that is commonly used in electronic circuits to generate precise and stable radio frequency (RF) signals. It is a highly integrated device that can produce frequencies up to 180 MHz with a resolution of 48 bits.

What are the main components of a circuit involving a AD9854 DDS?

A typical circuit involving a AD9854 DDS will include the AD9854 chip itself, a microcontroller or computer to control the chip, a power supply, and various supporting components such as capacitors, resistors, and inductors. The specific components and their values will depend on the desired application of the circuit.

How does a AD9854 DDS work?

The AD9854 DDS works by using a phase accumulator to generate a digital frequency value, which is then converted into an analog signal through a digital-to-analog converter. This analog signal is then amplified and filtered to produce a stable and precise RF output.

What are the advantages of using a AD9854 DDS in a circuit?

A AD9854 DDS offers several advantages over traditional analog frequency synthesizers. These include higher frequency resolution, better frequency stability, and the ability to easily change frequencies without the need for manual adjustments. It also allows for the generation of multiple frequencies simultaneously.

What are some common applications of a circuit involving a AD9854 DDS?

The AD9854 DDS is commonly used in radio communication systems, radar systems, test and measurement equipment, and other applications that require precise and stable RF signals. It is also often used in amateur radio projects and electronic hobbyist projects.

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