Analog Devices Inc. I vs E temperature spec

This is a very common question about temperature grades we get on Analog Devices parts that were acquired from Linear Technology through the acquisition.
 
There are several numbers that have the I and E suffix and call out the same temperature specs on the Digi-Key site. For example, LT8616IUDE#PBF and LT8616EUDE#PBF.
 

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LT8616IUDE#PBF
 

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LT8616EUDE#PBF

The difference between the suffixes is noted in the note section right after the electrical characteristics on the datasheet.

Per the datasheet LT8616 - Dual 42V Synchronous Monolithic Step-Down Regulator with 6.5µA Quiescent Current (analog.com)

Note 2: The LT8616E is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT8616I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT8616H is guaranteed over the full –40°C to
150°C operating junction temperature range.

Note Temp suffix meanings:
C - Commercial (0ºC to 70ºC)
E - Extended (-40ºC to 85ºC) “Assured by Design”
I - Industrial (-40ºC to 85ºC)
H - High Temp/Automotive (-40ºC to 140ºC)
MP - Military Plastic (-55ºC to 125ºC)

So, if you designed in the E suffix part and we are currently out of stock. But, we have the I suffix, then there should be no issues using the part as it is guaranteed over that full temp range. Please verify the Analog Devices datasheet and review the temp note before ordering.

Reference Doc:
Linear Tech (general ordering info)
LINEAR TECH part numbering info.pdf (49.6 KB)