GM71C(S)17400C/CL
18.
19.
In delayed write or read-modify-write cycles, OE must disable output buffer prior to applying
data to the device. After RAS is reset, if tOEH>=tCWL, the I/O pin will remain open circuit (high
impedance); if tOEH < tCWL, invalid data will be out at each I/O.
The 16M DRAM offers a 16-bit time saving parallel test mode. Address CA0 and CA1 for the
4M x 4 are don't care during test mode. Test mode is set by performing a WE-and-CAS-before-
RAS (WCBR) cycle. In 16-bit parallel test mode, data is written into 4 bits in parallel at each I/O
(I/O1 to I/O4) and read out from each I/O. If 4 bits of each I/O are equal (all 1s or 0s), data
output pin is a high state during test mode read cycle, then the device has passed. If they are not
equal, data output pin is a low state, then the device has failed. Refresh during test mode
operation can be performed by normal read cycles or by WCBR refresh cycles. To get out of test
mode and enter a normal operation mode, perform either a regular CAS-before-RAS refresh
cycle or RAS-only refresh cycle.
In a test mode read cycle, the value of tRAC, tAA, tCAC and tACP is delayed by 2ns to 5ns for the
specified value. These parameters should be specified in test mode cycles by adding the above
value to the specified value in this data sheet.
20.
Rev 0.1 / Apr’01
HYNIX [ HYNIX SEMICONDUCTOR ]
