Other Parts Discussed in Thread: ISOW7841,
I see the V_IOWM rating for the ISOW7841 (3/1 data + integrated power) and ISO7841 (3/1 data, no power) is very different:
- ISOW7841 DWE (>8mm clearance/creepage):
- 1000V RMS or
- 1414V DC
- Figure 42 1000V RMS for 1184 years
- ISO7841 DW (>8mm clearance/creepage):
- 1500V RMS or
- 2121V DC
- Figure 1: 1500V RMS for 135 years
- ISO7841 DWW (>14.5mm clearance/creepage):
- 2000V RMS or
- 2828V DC
- Figure 2: 2000V RMS for 34 years
I have an application where I need to measure 1V on a shunt resistor on top of a 1600V DC rail, which might go as high as 1850V without load.
From my interpretation, it seems like the actual basic insulation lifetime for all of these parts is exactly the same, it's just that a different "optimal" point on the insulation lifetime projection was selected for the datasheet. I understand that the wider DWW part, with higher creepage and clearance, allows for a higher safe working voltage (so, it rides further down the lifetime projection, with only 34 years lifetime, instead of 134 years).
However, I don't understand why the ISO7841DW is rated above the ISOW7841DWE. Are they not operating on the same lifetime projection curve?
Separately, what power supply is recommended for an ISO7841DWW implementation which actually requires the high V_IOWM rating?
Thanks,
Brian