Hyundai (HY) - 4 Megabit

How do I read the type number?

HY514400-60
^^----------------- HY = Hyundai
HY514400-60
  ^^^-------------- 514 = 4  Megabit chip
                    511 = 16 Megabit chip: see below
                    531 = 1  Megabit chip
                    534 = 1  Megabit chip
                    53C = 256 Kilobit chip
HY514400-60
     ^^^----------- Internal Organization & Refresh: 
                    100 = 4Meg x 1  / ??  refresh
                    260 = 256K x 16 / 512 refresh
                    400 = 1Meg x 4  / 1K  refresh
                    800 = 512K x 8  / 1K  refresh
HY514400-60
         ^^-------- Speed: 50=50ns / 60=60ns / 70=70ns / etc