[time-nuts] Power Supply for AD9852 / AD9854

Jim Lux jimlux at earthlink.net
Sun Mar 16 12:56:53 EDT 2014

On 3/16/14 9:34 AM, d0ct0r wrote:
> I would assume that using two voltage regulators will spread the load.
> For the AD9851 I'am planning to put external radiator glued on top of it.

It's not the power dissipation of the regulators that's the concern, 
it's the dissipation of the 9854.  A heatsink on top doesn't do much for 
it, since the thermal path is out through the bottom and/or the leads. 
Of course, if your regulators are sharing the thermal path, then 
dissipation in the regulators becomes a concern too.

Read the data sheet and the ap note for details.

The eval board works OK most of the time. I've encountered flaky 
behavior but that could have been from other causes.

The 9854 is the part that was used in the Flex-Radio SDR1000, but most 
of the options were powered off, so the dissipation was in the <1 watt 
range. That particular board would overheat in an enclosure if you 
didn't have a fan blowing on it.

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