CY7C1480V25
CY7C1482V25
CY7C1486V25
Document #: 38-05282 Rev. *G
Page 9 of 31
loaded
into
the
address
register
and
the
address
advancement logic while being delivered to the memory array.
The ADV input is ignored during this cycle. If a global Write is
conducted, the data presented to the DQs is written into the
corresponding address location in the memory core. If a Byte
Write is conducted, only the selected bytes are written. Bytes
not selected during a Byte Write operation will remain
unaltered. A synchronous self-timed Write mechanism has
been provided to simplify the Write operations.
Because CY7C1480V25/CY7C1482V25/CY7C1486V25 is a
common I/O device, the Output Enable (OE) must be
deasserted HIGH before presenting data to the DQs inputs.
Doing so will tri-state the output drivers. As a safety
precaution, DQs are automatically tri-stated whenever a Write
cycle is detected, regardless of the state of OE.
Burst Sequences
The CY7C1480V25/CY7C1482V25/CY7C1486V25 provides
a two-bit wraparound counter, fed by A1: A0, that implements
either an interleaved or linear burst sequence. The interleaved
burst sequence is designed specifically to support Intel
Pentium applications. The linear burst sequence is designed
to support processors that follow a linear burst sequence. The
burst sequence is user selectable through the MODE input.
Asserting ADV LOW at clock rise will automatically increment
the burst counter to the next address in the burst sequence.
Both Read and Write burst operations are supported.
Sleep Mode
The ZZ input pin is an asynchronous input. Asserting ZZ
places the SRAM in a power conservation “sleep” mode. Two
clock cycles are required to enter into or exit from this “sleep”
mode. While in this mode, data integrity is guaranteed.
Accesses pending when entering the “sleep” mode are not
considered valid nor is the completion of the operation
guaranteed. The device must be deselected prior to entering
the “sleep” mode. CE1, CE2, CE3, ADSP, and ADSC must
remain inactive for the duration of tZZREC after the ZZ input
returns LOW.
Interleaved Burst Address Table
(MODE = Floating or VDD)
First
Address
A1: A0
Second
Address
A1: A0
Third
Address
A1: A0
Fourth
Address
A1: A0
00
01
10
11
01
00
11
10
10
11
00
01
11
10
01
00
Linear Burst Address Table
(MODE = GND)
First
Address
A1: A0
Second
Address
A1: A0
Third
Address
A1: A0
Fourth
Address
A1: A0
00
01
10
11
01
10
11
00
10
11
00
01
11
00
01
10
ZZ Mode Electrical Characteristics
Parameter
Description
Test Conditions
Min.
Max.
Unit
IDDZZ
Sleep mode standby current
ZZ > VDD – 0.2V
120
mA
tZZS
Device operation to ZZ
ZZ > VDD – 0.2V
2tCYC
ns
tZZREC
ZZ recovery time
ZZ < 0.2V
2tCYC
ns
tZZI
ZZ Active to sleep current
This parameter is sampled
2tCYC
ns
tRZZI
ZZ Inactive to exit sleep current
This parameter is sampled
0
ns
Truth Table[2, 3, 4, 5, 6]
Operation
Add. Used
CE1 CE2 CE3 ZZ ADSP ADSC ADV WRITE OE CLK
DQ
Deselect Cycle, Power Down
None
H
X
X
L
X
L
X
X
X
L-H Tri-State
Deselect Cycle, Power Down
None
L
L
X
L
L
X
X
X
X
L-H Tri-State
Deselect Cycle, Power Down
None
L
X
H
L
L
X
X
X
X
L-H Tri-State
Deselect Cycle, Power Down
None
L
L
X
L
H
L
X
X
X
L-H Tri-State
Deselect Cycle, Power Down
None
L
X
H
L
H
L
X
X
X
L-H Tri-State
Sleep Mode, Power Down
None
X
X
X
H
X
X
X
X
X
X
Tri-State
READ Cycle, Begin Burst
External
L
H
L
L
L
X
X
X
L
L-H
Q
READ Cycle, Begin Burst
External
L
H
L
L
L
X
X
X
H
L-H Tri-State
Notes:
2. X = “Don't Care.” H = Logic HIGH, L = Logic LOW.
3. WRITE = L when any one or more Byte Write enable signals and BWE = L or GW = L. WRITE = H when all Byte write enable signals, BWE, GW = H.
4. The DQ pins are controlled by the current cycle and the OE signal. OE is asynchronous and is not sampled with the clock.
5. The SRAM always initiates a read cycle when ADSP is asserted, regardless of the state of GW, BWE, or BWX. Writes may occur only on subsequent clocks
after the ADSP or with the assertion of ADSC. As a result, OE must be driven HIGH prior to the start of the write cycle to allow the outputs to tri-state. OE is a
don't care for the remainder of the write cycle
6. OE is asynchronous and is not sampled with the clock rise. It is masked internally during write cycles. During a read cycle all data bits are Tri-State when OE is
inactive or when the device is deselected, and all data bits behave as output when OE is active (LOW).
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