Differences between HMC7044 and the new HMC7044B?

Hi, 

It is discovered that HMC7044 has some ppm synchronization error under certain cold die temperatures and low supply voltage conditions. This synchronization error occurs in temperatures lower than -10 ℃ and supply voltage lower than nominal values.
This synchronization error results from the pulse generation mechanism. This synchronization problem doesn’t occur when continuous SYSREF or CLK is used.
HMC7044B is the revised version designed to overcome this synchronization problem in the pulse generation mechanism. There is no difference between HMC7044 and HMC7044B in terms of Fit, Form, Function, and Software.
Even though there is no difference between HMC7044 and HMC7044B functionality-wise, We recommend HMC7044B for new designs. 

If you want to swap HMC7044 in your system with HMC7044B, there is no need for software and hardware changes. You can move on with just a BOM change. If you would like to differentiate two parts, HMC7044B has an option for product ID change.

Thanks,

Emrecan

Many thanks Emrecan for such a quick and relevant answer : "there is no difference between HMC7044 and HMC7044B in terms of Fit, Form, Function, and Software".

Excellent!

Hi Emrecan,

You state "There is no difference between HMC7044 and HMC7044B in terms of Fit, Form, Function, and Software." Is there any difference in performance, beside the mentioned synchronization error? Is there any reason to keep using HMC7044 in existing designs, or can we safely switch to HMC7044B?

Also: Currently, the HMC7044 has status "Recommended for new designs"... Is this expected to change soon?

Hi,

We plan to change HMC7044's status to "Not Recommended for New Designs." However, we are waiting for the evaluation boards for HMC7044B. 

If all the outputs of the HMC7044 are enabled and the temperature is well controlled, there is no reason to switch to HMC7044B for the current design.

There is no performance difference between the two parts. However, we recommend switching to HMC7044B. You can safely switch to HMC7044B. Only BOM change is enough. Even the registers are the same for software compatibility. 

Thanks,

Emrecan

Hi,

Actually, in our design the HMC7044 runs quite hot. I believe this may be due to lack of sufficient cooling; the GND plane where the thermal pad connects to, is not very large; it's on some kind of peninsula. Sometimes a part fails to lock the integrated VCO of PLL2. Cooling the chip then solves the issue.

Is this a condition in which the HMC7044B may perform better?

Thanks,
Johannes

In these conditions, HMC7044 will perform the same as HMC7044B. 

The issue is related to cold die temperatures. 

Are you sending a restart request after completing the register configuration to start the VCO autocalibration to resolve the lock issue? 

Normally HMC7044 VCO is designed to cover lock and leave over the full operation temperature. However, Please be aware that the stress over the maximum operation temperatures can harm the device. 

Thanks,
Emrecan