These identity comparators perform comparisons on two 8-bit binary
or BCD words. The SN74ALS518 provides P = Q outputs, while the
´ALS520 and SN74ALS521 provide P = Q\ outputs. The SN74ALS518
has an open-collector output. The SN74ALS518 and ´ALS520 feature
20-k pullup resistors on the Q inputs for analog or switch data.
The SN54ALS520 is characterized for operation over the full
military temperature range of -55°C to 125°C. The
SN74ALS518, SN74ALS520, and SN74ALS521 are characterized for
operation from 0°C to 70°C.