A4016U4X
WCMA4016U4X
256K x 16 Static RAM
Features
• Low Voltage range:
— 2.7V-3.3V
• Ultra-low active power
— Typical active current: 1.5 mA @ f = 1MHz
•
•
•
•
— Typical active current: 7 mA @ f = f
max
Low standby power
Easy memory expansion with CE and OE features
Automatic power-down when deselected
CMOS for optimum speed/power
more than 99% when deselected (CE HIGH or both BLE and
BHE are HIGH). The input/output pins (I/O
0
through I/O
15
) are
placed in a high-impedance state when: deselected (CE
HIGH), outputs are disabled (OE HIGH), both Byte High En-
able and Byte Low Enable are disabled (BHE, BLE HIGH), or
during a write operation (CE LOW and WE LOW).
Writing to the device is accomplished by taking Chip Enable
(CE) and Write Enable (WE) inputs LOW. If Byte Low Enable
(BLE) is LOW, then data from I/O pins (I/O
0
through I/O
7
), is
written into the location specified on the address pins (A
0
through A
17
). If Byte High Enable (BHE) is LOW, then data
from I/O pins (I/O
8
through I/O
15
) is written into the location
specified on the address pins (A
0
through A
17
).
Reading from the device is accomplished by taking Chip
Enable (CE) 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 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 at the back of this data sheet for a complete
description of read and write modes.
The WCMA4016U4X is available in a 48-ball FBGA package.
Functional Description
The WCMA4016U4X is a high-performance CMOS static
RAMs organized as 256K words by 16 bits. These devices
feature advanced circuit design to provide ultra-low active cur-
rent. This device is ideal for portable applications such as cel-
lular telephones. The devices also have an automatic pow-
er-down feature that significantly reduces power consumption
by 80% when addresses are not toggling. The device can also
be put into standby mode reducing power consumption by
Logic Block Diagram
DATA IN DRIVERS
A
10
A
9
A
8
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
ROW DECODER
256K x 16
RAM Array
2048 x 2048
SENSE AMPS
I/O
0
– I/O
7
I/O
8
– I/O
15
COLUMN DECODER
BHE
WE
CE
OE
BLE
A
11
A
12
A
13
A
14
A
15
A
16
CE
Pow
-
er Down
Circuit
BHE
BLE
A
17
WEIDA [ WEIDA SEMICONDUCTOR, INC. ]
