CY7C1470BV25
CY7C1472BV25, CY7C1474BV25
Document #: 001-15032 Rev. *D Page 9 of 29
access (read, write, or deselect) is latched into the Address
Register (provided the appropriate control signals are asserted).
On the next clock rise the data presented to DQ and DQP
(DQa,b,c,d/DQPa,b,c,d for CY7C1470BV25, DQa,b/DQPa,b for
CY7C1472BV25, DQa,b,c,d,e,f,g,h/DQPa,b,c,d,e,f,g,h for
CY7C1474BV25) (or a subset for Byte Write operations, see
“Partial Write Cycle Description” on page11 for details) inputs is
latched into the device and the Write is complete.
The data written during the Write operation is controlled by BW
(BWa,b,c,d for CY7C1470BV25, BWa,b for CY7C1472BV25, and
BWa,b,c,d,e,f,g,h for CY7C1474BV25) signals. The
CY7C1470BV25, CY7C1472BV25, and CY7C1474BV25
provides Byte Write capability that is described in “Partial Write
Cycle Description” on page11. Asserting the WE input with the
selected BW input selectively writes to only the desired bytes.
Bytes not selected during a Byte Write operation remain
unaltered. A synchronous self-timed write mechanism has been
provided to simplify the write operations. Byte Write capability
has been included to greatly simplify read, modify, or write
sequences, which can be reduced to simple Byte Write opera-
tions.
Because the CY7C1470BV25, CY7C1472BV25, and
CY7C1474BV25 are common IO devices, data must not be
driven into the device while the outputs are active. OE can be
deasserted HIGH before presenting data to the DQ and DQP
(DQa,b,c,d/DQPa,b,c,d for CY7C1470BV25, DQa,b/DQPa,b for
CY7C1472BV25, and DQa,b,c,d,e,f,g,h/DQPa,b,c,d,e,f,g,h for
CY7C1474BV25) inputs. Doing so tri-states the output drivers.
As a safety precaution, DQ and DQP (DQa,b,c,d/DQPa,b,c,d for
CY7C1470BV25, DQa,b/DQPa,b for CY7C1472BV25, and
DQa,b,c,d,e,f,g,h/DQPa,b,c,d,e,f,g,h for CY7C1474BV25) are
automatically tri-stated during the data portion of a write cycle,
regardless of the state of OE.
Burst Write Accesses
The CY7C1470BV25, CY7C1472BV25, and CY7C1474BV25
has an on-chip burst counter that enables the user to supply a
single address and conduct up to four write operations without
reasserting the address inputs. ADV/LD must be driven LOW to
load the initial address, as described in “Single Write Accesses”
on page 8. When ADV/LD is driven HIGH on the subsequent
clock rise, the Chip Enables (CE1, CE2, and CE3) and WE inputs
are ignored and the burst counter is incremented. The correct
BW (BWa,b,c,d for CY7C1470BV25, BWa,b for CY7C1472BV25,
and BWa,b,c,d,e,f,g,h for CY7C1474BV25) inputs must be driven
in each cycle of the burst write to write the correct bytes of data.

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 before entering the “sleep” mode. CE1, CE2,
and CE3, must remain inactive for the duration of tZZREC after the
ZZ input returns LOW.
Table 2. Linear Burst Address Table (MODE = GND)
First
Address Second
Address Third
Address Fourth
Address
A1,A0 A1,A0 A1,A0 A1,A0
00 01 10 11
01 10 11 00
10 11 00 01
11 00 01 10
Table 3. Interleaved Burst Address Table
(MODE = Floating or VDD)
First
Address Second
Address Third
Address Fourth
Address
A1,A0 A1,A0 A1,A0 A1,A0
00 01 10 11
01 00 11 10
10 11 00 01
11 10 01 00
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
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