Task -- replace W9825G6JH 4 M x 4banks x 16 BITS SDRAM in 54 tsop2 with HY5DU121622CTP-D43 8M x 4banks x 16bits in 66 tsop2.

Legend:
66 pin chip

54 pin chip

Possible questionable things:
1.. LDQS, UDQS situation. Not used?
2.. VREF. Should come on after VDDQ. What to do?
3.. LDM, UDM situation. Does connecting to LDQM and UDQM looks legit?
4.. /CK differential. Can it just be connected to CK?
Datasheets:
54 pin chip --
W9825G6JH.PDF (803.78 kB - downloaded 21 times.)
66 pin chip --
HYSCS02664-1.pdf (1623.9 kB - downloaded 22 times.)
What do you think?
