Are the LTC2983/LTC2984/LTC2986/LTC2986-1 interchangeable?
The LTC298x family consists of pin and software compatible parts that differ in their number of channels and inclusion of EEPROM. LTC2983 (without EEPROM) and LTC2984 (with EEPROM) are both 20-channel Multisensor high Accuracy Digital Temperature Measurement Systems. LTC2986 and LTC2986-1 are 10-channel versions of the LTC2983 and LTC2984 respectively. They are all pin- and software-compatible, just note how many channels you need and whether or not you need an EEPROM.
The LTC298x family now includes the LTM2985. It comes in a 66-ld BGA package (vs the rest of the family which comes in 48-ld LQFP) but is software compatible with the LTC2986-1.