8-Mbit (512K x 16) Static RAM
CY62157E MoBL
®
Cypress Semiconductor Corporation
•
198 Champion Court
•
San Jose
,
CA 95134-1709
•
408-943-2600
Document #: 38-05695 Rev. *C
Revised November 21, 2006
Features
• Very high speed: 45 ns
• Wide voltage range: 4.5V–5.5V
• Ultra-low standby power
—Typical Standby current: 2
µ
A
—Maximum Standby current: 8
µ
A (Industrial)
• Ultra-low active power
— Typical active current: 1.8 mA @ f = 1 MHz
• Ultra-low standby power
• Easy memory expansion with CE
1
, CE
2
and OE features
• Automatic power-down when deselected
• CMOS for optimum speed/power
• Available in Pb-free 44-pin TSOP II and 48-ball VFBGA
package
Functional Description
[1]
The CY62157E is a high-performance CMOS static RAM
organized as 512K words by 16 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.
The device can also be put into standby mode when
deselected (CE
1
HIGH or CE
2
LOW or both BHE and BLE are
HIGH). The input/output pins (IO
0
through IO
15
) are placed in
a high-impedance state when: deselected (CE
1
HIGH or CE
2
LOW), outputs are disabled (OE HIGH), both Byte High
Enable and Byte Low Enable are disabled (BHE, BLE HIGH),
or during a write operation (CE
1
LOW, CE
2
HIGH and WE
LOW).
Writing to the device is accomplished by taking Chip Enable
(CE
1
LOW and CE
2
HIGH) and Write Enable (WE) input LOW.
If Byte Low Enable (BLE) is LOW, then data from IO pins (IO
0
through IO
7
), is written into the location specified on the
address pins (A
0
through A
18
). If Byte High Enable (BHE) is
LOW, then data from IO pins (IO
8
through IO
15
) is written into
the location specified on the address pins (A
0
through A
18
).
Reading from the device is accomplished by taking Chip
Enable (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 will appear on IO
0
to IO
7
. If Byte
High Enable (BHE) is LOW, then data from memory will appear
on IO
8
to IO
15
. See the truth table at the back of this data sheet
for a complete description of read and write modes.
Note:
1. For best practice recommendations, please refer to the Cypress application note “System Design Guidelines” on http://www.cypress.com.
Logic Block Diagram
512K x 16
RAM Array
IO
0
–IO
7
RO
W DE
CO
DE
R
A
8
A
7
A
6
A
5
A
2
COLUMN DECODER
A
11
A
12
A
13
A
14
A
15
SE
NS
E AM
P
S
DATA IN DRIVERS
OE
A
4
A
3
IO
8
–IO
15
WE
BLE
BHE
A
16
A
0
A
1
A
17
A
9
BHE
BLE
A
10
A
18
POWER-DOWN
CIRCUIT
CE
2
CE
1
CE
2
CE
1
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