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UCD9244: Intermittent supply drop

Part Number: UCD9244
Other Parts Discussed in Thread: TMS320C6678, UCD74120, UCD7242

This is a continuation of a previous post "UCD9244: over-current fault".

I am using a UCD9244 in combination with two UCD74120 and a UCD7242 to supply  two TMS320C6678 DSPs.  The UCD7242 is being utilized to supply 1.0V and 1.5V, the UCD74120s are supplying CVDD.

I am now in production with the boards, and have found that on most of the boards there is an intermittent drop in the 1.0V supply.  The recommended operating value for the C6678 is 0.95 to 1.05.  I am utilizing a separate power monitor chip.  I have been able to catch the failure mode once since it is so intermittent.  When observed it appears that the 1.0V supply drops to 0.92 or less for at least 300 uS which in turn causes the board power monitor to shut the board down.

Previously there was a bunch of jitter on the 1.5V supply PWM and TI supplied a Fusion project that cleaned up the jitter and solved my 1.5V problem.  I have observed some of the same jitter on the 1.0V supplies PWM.  I have also been trying to tweak the compensation of the 1.0V supply without much success.

Any suggestions would be appreciated.