FM21LD16 - 128Kx16 FRAM
Functional Truth Table 1,2
/CE
H
↓
/WE
X
H
A(16:2)
A(1:0)
Operation
Standby/Idle
Read
X
V
X
V
L
L
↓
L
L
↑
H
H
L
↓
↓
X
No Change
Change
Change
Page Mode Read
Random Read
/CE-Controlled Write
/WE-Controlled Write 2
Page Mode Write 3
Starts Precharge
V
V
V
V
X
V
V
No Change
X
Notes:
1) H=Logic High, L=Logic Low, V=Valid Data, X=Don’t Care.
2) /WE-controlled write cycle begins as a Read cycle and A(16:2) is latched then.
3) Addresses A(1:0) must remain stable for at least 10 ns during page mode operation.
4) For write cycles, data-in is latched on the rising edge of /CE or /WE, whichever comes first.
Byte Select Truth Table
/OE
H
X
/LB
X
H
H
L
/UB
X
H
L
H
L
Operation
Read; Outputs Disabled
L
Read; DQ(7:0) Hi-Z
Read; DQ(15:8) Hi-Z
Read
L
X
H
L
L
L
H
L
Write; Mask DQ(7:0)
Write; Mask DQ(15:8)
Write
The /UB and /LB pins may be grounded if 1) the system does not
perform byte writes and 2) the device is not configured as a 256Kx8.
Rev. 1.0
Dec. 2009
Page 3 of 14
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
