Jonathan,

Attached is an Excel file I have worked on for PacSat power needs.

Bob

On Jan 20, 2023, at 7:17 AM, Jonathan Brandenburg via pacsat-dev <pacsat-dev@amsat.orgmailto:pacsat-dev@amsat.org> wrote:

I seem to remember that, too. As such, we may need to look at other parts or different versions of the same parts. That depends, obviously on the maximum current draw expected during normal operation. Does anybody on this list know if we have that information for the AX5043 chain?

Jonathan

On 1/19/23 17:40, Rich Gopstein via pacsat-dev wrote: Burns might remember the details (or Zach certainly would), but one of those parts was undersized for the RT-IHU and would cut out when we were transmitting with the ax5043. I think we had to back down the xmit power in order for the device not to reset.

Rich

On Thu, Jan 19, 2023 at 5:46 PM Jonathan Brandenburg via pacsat-dev <pacsat-dev@amsat.orgmailto:pacsat-dev@amsat.org> wrote: In last week's meeting, I noted I had been looking at the schematics for Fox-1 and RT-IHU and found the circuits for the latchup protection and watchdog functions. I admit this might be basic to some, but I'm finding it fascinating! Anyway...

Since last week's meeting, I researched the parts used:

onsemi FPF2001 is a current limit switch used on both Fox-1 and half the RT-IHU. It's obsolete, replaced by onsemi's FPF2000. But the FPF2000 is listed as end-of-life. It's replacement part is the TI TPS22942.

MAX4995 is a current limit switch used on the other half of the. This part looks good for new designs.

For the watchdog functionality, both Fox-1 and RT-IHU use the STWD100NYWY3F chip. this parts looks good for new designs.

That's as far as I got. Next, I want to research the Fox-1 and RT-IHU designs to determine the thresholds of the current limit switches. In particular, I want to see if the TPS22942 is a suitable replacement, assuming we have the same current requirements.

That's where I'm at,

Jonathan

-- Jonathan Brandenburg Radio Amateur Satellite Corporation 1-214-213-1066

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-- Jonathan Brandenburg Radio Amateur Satellite Corporation 1-214-213-1066

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