CYK256K16SCCB
4-Mbit (256K x 16) Pseudo Static RAM
Features
鈥?Advanced low-power MoBL
庐
architecture
鈥?High speed: 55 ns, 60 ns and 70 ns
鈥?Wide voltage range: 2.7V to 3.3V
鈥?Typical active current: 1 mA @ f = 1 MHz
鈥?Low standby power
鈥?Automatic power-down when deselected
in portable applications such as cellular telephones. The
device can be put into standby mode reducing power
consumption dramatically when deselected (CE
1
LOW, CE
2
HIGH or both BHE and BLE are HIGH). The input/output pins
(I/O
0
through I/O
15
) are placed in a high-impedance state
when: deselected (CE
1
HIGH, CE
2
LOW, OE is deasserted
HIGH), or during a write operation (Chip Enabled and Write
Enable WE LOW).
Reading from the device is accomplished by asserting the
Chip Enables (CE
1
LOW and CE
2
HIGH) and Output Enable
(OE) LOW while forcing the Write Enable (WE) HIGH. If Byte
Low Enable (BLE) is LOW, then data from the memory location
specified by the address pins A
0
through A
17
will appear on
I/O
0
to I/O
7
. If Byte High Enable (BHE) is LOW, then data from
memory will appear on I/O
8
to I/O
15
. See the Truth Table for a
complete description of read and write modes.
Functional Description
[1]
The CYK256K16SCCB is a high-performance CMOS pseudo
static RAM (PSRAM) organized as 256K words by 16 bits that
supports an asynchronous memory interface. This device
features advanced circuit design to provide ultra-low active
current. This is ideal for providing More Battery Life鈩?(MoBL)
Logic Block Diagram
A
10
A
9
A
8
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
DATA IN DRIVERS
ROW DECODER
256K x 16
RAM Array
SENSE AMPS
I/O
0
鈥揑/O
7
I/O
8
鈥揑/O
15
COLUMN DECODER
BHE
WE
OE
BLE
BHE
BLE
CE
2
CE
1
CE
2
CE
1
Note:
1. For best-practice recommendations, please refer to the Cypress application note 鈥淪ystem Design Guidelines鈥?on http://www.cypress.com.
A
11
A
12
A
13
A
14
A
15
A
16
A
17
Pow
-
er Down
Circuit
Cypress Semiconductor Corporation
Document #: 38-05526 Rev. *H
鈥?/div>
198 Champion Court
鈥?/div>
San Jose
,
CA 95134-1709
鈥?/div>
408-943-2600
Revised October 18, 2006
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