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STD130
5-182
Samsung ASIC
SPSRAMBW_LP
Low-Power Single-Port Synchronous Static RAM with Bit-Write
Logic Symbol
Function Description
SPSRAMBW_LP is a single-port synchronous static RAM with bit-write capability which is provided as a
compiler. SPSRAMBW_LP is intended for use in Low-Power applications. Basically, its functionality is
exactly same as SPSRAM_LP except a bit-write operation which is controlled by BWEN[], named bit-write
enable signal bus. Each bit of BWEN[] enables or disable the write operation of its corresponding bit in DI[].
On the rising edge of CK, the write cycle is initiated when WEN is low and CSN is low. The data bytes or bits
in DI[], which their corresponding bit(s) in BWEN[] are low, are written into the memory location specified on
A[]. When all bits of BWEN[] are high, any data in DI[] are not written into the memory location specified on
A[]. When all bits of BWEN[] are low, the data in DI[] are written into the memory location specified on A[],
which is exactly same as the write operation in SPSRAM_LP. During the write cycle, DOUT[] remains stable.
On the rising edge of CK, the read cycle is initiated when WEN is high and CSN is low. The data at DOUT[]
become valid after a delay. While in standby mode that CSN is high, A[] and DI[] are disabled, data stored in
the memory is retained and DOUT[] remains stable. When OEN is high, DOUT[] is placed in a
high-impedance state.
SPSRAMBW_LP Function Table
CK
X
X
↑
↑
↑
↑
CSN
X
H
L
L
L
L
WEN
X
X
L
L
L
H
OEN
H
L
L
L
L
L
A
X
X
BWEN
X
X
all L
L
all H
X
DI
X
X
DOUT
Z
DOUT(t-1)
DOUT(t-1)
DOUT(t-1)
DOUT(t-1)
MEM(A)
Comment
Unconditional tri-state output
De-selected (standby mode)
Word-write cycle
Bit-write cycle
No operation
Read cycle
Valid
Valid
Valid
Valid
Valid
Valid
Valid
X
Features
Suitable f
or low-po
wer application
Bit-write capability
Separated data I/O
Synchronous operation
Duty-free clock cycle
Asynchronous tri-state output control
Latched inputs and outputs
Automatic power-down
Zero standby current
Zero hold time
Low noise output optimization
Flexible aspect ratio
Up to 512K bits capacity
Up to 16K number of words
Up to 256 number of bits per word
CK
CSN
WEN
OEN
A [m-1:0]
DI [b–1:0]
spsrambw_lp_<w>x<b>m<y>
DOUT [b–1:0]
NOTES:
1. Words(w) is the number of words.
2. Bpw(b) is the number of bits per word.
3. Ymux(y) is one of the column mux types.
4. m =
log
2
w
BWEN[b-1:0]