Cypress Semiconductor Corporation
•
198 Champion Court
•
San Jose
,
CA 95134-1709
•
408-943-2600
Document #: 001-13194 Rev. *A
Revised March 26, 2007
CY62138F MoBL
®
2-Mbit (256K x 8) Static RAM
Features
• High speed: 45 ns
• Wide voltage range: 4.5 V – 5.5 V
• Pin compatible with CY62138V
• Ultra low standby power
— Typical standby current:
1
µ
A
— Maximum standby current:
5
µ
A
• Ultra low active power
— Typical active current: 1.6 mA @ f = 1 MHz
• Easy memory expansion with CE
1
, CE
2,
and OE features
• Automatic power down when deselected
• CMOS for optimum speed and power
• Available in Pb-free 32-pin SOIC and 32-pin TSOP II
packages
Functional Description
[1]
The CY62138F is a high performance CMOS static RAM
organized as 256K words by 8 bits. This device features
advanced circuit design to provide ultra low active current.
This is ideal for providing More Battery Life™ (MoBL
®
) in
portable applications such as cellular telephones. The device
also has an automatic power down feature that significantly
reduces power consumption when addresses are not toggling.
Placing the device into standby mode reduces power
consumption by more than 99% when deselected (CE
1
HIGH
or CE
2
LOW).
To write to the device, take Chip Enable (CE
1
LOW and CE
2
HIGH) and Write Enable (WE) inputs LOW. Data on the eight
IO pins (IO
0
through IO
7
) is then written into the location
specified on the address pins (A
0
through A
17
).
To read from the device, take Chip Enable (CE
1
LOW and CE
2
HIGH) and output enable (OE) LOW while forcing Write
Enable (WE) HIGH. Under these conditions, the contents of
the memory location specified by the address pins appear on
the IO pins.
The eight input and output pins (IO
0
through IO
7
) are placed
in a high impedance state when the device is deselected (CE
1
HIGH or CE
2
LOW), the outputs are disabled (OE HIGH), or
during a write operation (CE
1
LOW and CE
2
HIGH and WE
LOW).
Logic Block Diagram
A0
IO0
IO7
IO1
IO2
IO3
IO4
IO5
IO6
A1
A2
A3
A4
A5
A6
A7
A8
A9
SENSE AMPS
POWER
DOWN
WE
OE
A
13
A
14
A
15
A
16
ROW DECODER
COLUMN DECODER
256K x 8
ARRAY
DATA IN DRIVERS
A10
A11
A
17
CE1
CE2
A
12
Note
1. For best practice recommendations, refer to the Cypress application note
“System Design Guidelines”
at
http://www.cypress.com.
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