The LTC4013 has "E" and "I" versions. What is the difference between them?
The price of I version is higher than that of E version, the I version is for an automotive market?
Take a look at Note 2 under the spec table on page 5. Essentially, the E-grade performance is guaranteed through testing over part of the temperature range and by design over the full range. The I-grade performance is guaranteed through testing over the full temperature range.
The I-grade is not exclusively for the automotive market but it is generally preferred for more critical applications, so it is a common choice for automotive applications.