12-19-2019 06:41 PM
It thinks the power supply sequence of KINTEX-7( XC7K410T-2FFV900I) is done in the following order referring to DS182.
(1) [1.0V] VCCINT, VCCBRAM,MGTAVCC
(2) [1.2V] MGTAVTT
(3) [1.8V] VCCAUX, VCCAUX_IO_GO, VCCADC_0,MGTVCCAUX
(4) [3.3V] VCCOx
(5) [2.5V] VCCOy, [1.5V]VCCOz
Is there a problem in the device if the voltage of about 1V might be given to VCCOx(for 3.3V) ahead of (1)?
It is described in Power-On/Off Power Supply Sequencing of DS182,
"The voltage difference between VCCO and VCCAUX must not exceed 2.625V for longer than TVCCO2VCCAUX for each power-on/off cycle to maintain device reliability levels."
Is it correct though it is thought that it only has to be "VCCO-VCCAUX <2.625V" from this description?
12-19-2019 06:57 PM
1. For the 1V in 3.3V rail, you supply it or it's some reverse current? It's best to avoid this but no official spec here.
2. For the 2.625V spec, if you can guarantee there is always a <2.625V difference for both power on and off procedure, that's OK. If you got it bigger than 2.625V, and this time duration is longer than Tvcco2vccaux, device damage might be seen.