Rainbow Electronics W24257 User Manual
W24257
CS
WE
OE
32K × 8 CMOS STATIC RAM
8GENERAL DESCRIPTION
The W24257 is a slow speed, low power CMOS static RAM organized as 32768 × 8 bits that operates
on a single 5-volt power supply. This device is manufactured using Winbond's high performance
CMOS technology.
FEATURES
• Low power consumption:
− Active: 400 mW (max.)
− Standby: 250 µW (max.) (LL-version)
500 µW (max.) (L-version)
• Access time: 70/100 nS (max.)
• Single +5V power supply
• Fully static operation
PIN CONFIGURATION
A14
A12
1
2
3
A7
4
A6
5
A5
A4
6
7
A3
8
A2
28
27
26
25
24
23
22
21
V
WE
A13
A8
A9
A11
OE
A10
• All inputs and outputs directly TTL compatible
• Three-state outputs
• Battery back-up operation capability
• Data retention voltage: 2V (min.)
• Available packages: 28-pin 600 mil DIP, 330
mil SOP, 300 mil skinny DIP and SOJ
BLOCK DIAGRAM
V
DD
SS
V
DD
A14
CS
OE
WE
A0
.
DECODER
.
CONTROL
CORE
ARRAY
DATA I/O
I/O1
I/O8
.
.
I/O1
I/O2
I/O3
A1
9
A0
10
11
12
13
V
14
SS
20
CS
19
I/O8
I/O7
18
I/O6
17
16
I/O5
I/O4
15
PIN DESCRIPTION
SYMBOL DESCRIPTION
A0−A14
I/O1−I/O8
Address Inputs
Data Inputs/Outputs
Chip Select Input
Write Enable Input
Output Enable Input
VDD Power Supply
VSS Ground
Publication Release Date: April 1997
- 1 - Revision A11
TRUTH TABLE
CSOEWE
WE
Operating Power
CS
Supply Current
CS
CS
W24257
MODE
H X X Not Selected High Z ISB, ISB1
L H H Output Disable High Z IDD
L L H Read Data Out IDD
L X L Write Data In IDD
I/O1−I/O8
VDD CURRENT
DC CHARACTERISTICS
Absolute Maximum Ratings
PARAMETER RATING UNIT
Supply Voltage to VSS Potential -0.5 to +7.0 V
Input/Output to VSS Potential -0.5 to VDD +0.5 V
Allowable Power Dissipation 1.0 W
Storage Temperature -65 to +150
Operating Temperature 0 to +70
Note: Exposure to conditions beyond those listed under Absolute Maximum Ratings may adversely affect the life and reliability of the
device.
Operating Characteristics
(VDD = 5V ±10%, VSS = 0V, TA = 0 to 70° C)
PARAMETER SYM. TEST CONDITIONS MIN. TYP. MAX. UNIT
Input Low Voltage VIL - -0.5 - +0.8 V
Input High Voltage VIH - +2.2 - VDD +0.5 V
Input Leakage Current ILI VIN = VSS to VDD -2 - +2
Output Leakage
Current
Output Low Voltage VOL IOL = +4.0 mA - - 0.4 V
Output High Voltage VOH IOH = -1.0 mA 2.4 - - V
Standby Power
Supply Current
Note: Typical characteristics are at VDD = 5V, TA = 25° C.
ILO
IDD
ISB
ISB1
VI/O = VSS to VDD, CS = VIH
(min.) or OE = VIH (min.) or
= VIL (max.)
= VIL (min.),
I/O = 0 mA
Cycle = min.,
Duty = 100%
= VIH (min.)
Cycle = min., Duty = 100%
≥ VDD -0.2V
-2 - + 2
70 - - 80 mA
100 - - 70 mA
- - 3 mA
LL - - 50
L - - 100
°C
°C
µA
µA
µA
µA
- 2 -
W24257
CAPACITANCE
(VDD = 5V, TA = 25° C, f = 1 MHz)
PARAMETER SYM. CONDITIONS MAX. UNIT
Input Capacitance CIN VIN = 0V 6 pF
Input/Output Capacitance CI/O VOUT = 0V 8 pF
Note: These parameters are sampled but not 100% tested.
AC CHARACTERISTICS
AC Test Conditions
PARAMETER CONDITIONS
Input Pulse Levels 0.6V to 2.4V
Input Rise and Fall Times 5 nS
Input and Output Timing Reference Level 1.5V
Output Load CL = 100 pF, IOH/IOL = -1 mA/4 mA
AC Test Loads and Waveform
R1 1000 ohm
5V
OUTPUT
100 pF
Including
Jig and
Scope
R2
660 ohm
3.0V
0V
5 nS
90% 90%
10%
10%
OUTPUT
(For T
5 nS
5V
CLZ
OLZ TCHZ T
, ,
T
,
R1 1000 ohm
5 pF
Including
Jig and
Scope
OHZ
,
T
WHZ
R2
660 ohm
,
)
OW
T
Publication Release Date: April 1997
- 3 - Revision A11
W24257
CS, WE
AC Characteristics, continued
(VDD = 5V ±10%, VSS = 0V, TA = 0 to 70° C)
Read Cycle
PARAMETER SYM. W24257-70 W24257-10 UNIT
MIN. MAX. MIN. MAX.
Read Cycle Time TRC 70 - 100 - nS
Address Access Time TAA - 70 - 100 nS
Chip Select Access Time TACS - 70 - 100 nS
Output Enable to Output Valid TAOE - 35 - 50 nS
Chip Selection to Output in Low Z TCLZ* 10 - 10 - nS
Output Enable to Output in Low Z TOLZ* 5 - 5 - nS
Chip Deselection to Output in High Z TCHZ* - 30 - 35 nS
Output Disable to Output in High Z TOHZ* - 30 - 35 nS
Output Hold from Address Change TOH 10 - 10 - nS
∗ These parameters are sampled but not 100% tested
Write Cycle
PARAMETER SYM. W24257-70 W24257-10 UNIT
MIN. MAX. MIN. MAX.
Write Cycle Time TWC 70 - 100 - nS
Chip Selection to End of Write TCW 60 - 80 - nS
Address Valid to End of Write TAW 60 - 80 - nS
Address Setup Time TAS 0 - 0 - nS
Write Pulse Width TWP 45 - 60 - nS
Write Recovery Time
Data Valid to End of Write TDW 30 - 40 - nS
Data Hold from End of Write TDH 0 - 0 - nS
Write to Output in High Z TWHZ* - 30 - 30 nS
Output Disable to Output in High Z TOHZ* - 30 - 30 nS
Output Active from End of Write TOW 0 - 0 - nS
∗ These parameters are sampled but not 100% tested
TWR 0 - 0 - nS
- 4 -
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