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.
Supply Voltage to VSS Potential-0.5 to +7.0V
Input/Output to VSS Potential-0.5 to VDD +0.5V
Allowable Power Dissipation1.0W
Storage Temperature-65 to +150
Operating Temperature0 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)
PARAMETERSYM.TEST CONDITIONSMIN.TYP.MAX.UNIT
Input Low VoltageVIL--0.5-+0.8V
Input High VoltageVIH-+2.2-VDD +0.5V
Input Leakage CurrentILIVIN = VSS to VDD-2-+2
Output Leakage
Note: These parameters are sampled but not 100% tested.
AC CHARACTERISTICS
AC Test Conditions
PARAMETERCONDITIONS
Input Pulse Levels0.6V to 2.4V
Input Rise and Fall Times5 nS
Input and Output Timing Reference Level1.5V
Output LoadCL = 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
PARAMETERSYM.W24257-70W24257-10UNIT
MIN.MAX.MIN.MAX.
Read Cycle TimeTRC70-100-nS
Address Access TimeTAA-70-100nS
Chip Select Access TimeTACS-70-100nS
Output Enable to Output ValidTAOE-35-50nS
Chip Selection to Output in Low ZTCLZ*10-10-nS
Output Enable to Output in Low ZTOLZ*5-5-nS
Chip Deselection to Output in High ZTCHZ*-30-35nS
Output Disable to Output in High ZTOHZ*-30-35nS
Output Hold from Address ChangeTOH10-10-nS
∗These parameters are sampled but not 100% tested
Write Cycle
PARAMETERSYM.W24257-70W24257-10UNIT
MIN.MAX.MIN.MAX.
Write Cycle TimeTWC70-100-nS
Chip Selection to End of WriteTCW60-80-nS
Address Valid to End of WriteTAW60-80-nS
Address Setup TimeTAS0-0-nS
Write Pulse WidthTWP45-60-nS
Write Recovery Time
Data Valid to End of WriteTDW30-40-nS
Data Hold from End of WriteTDH0-0-nS
Write to Output in High ZTWHZ*-30-30nS
Output Disable to Output in High ZTOHZ*-30-30nS
Output Active from End of WriteTOW0-0-nS
∗ These parameters are sampled but not 100% tested
TWR0-0-nS
- 4 -
TIMING WAVEFORMS
AA
Read Cycle 1
(Address Controlled)
Address
DOUT
Read Cycle 2
(Chip Select Controlled)
W24257
T
RC
T
T
OH
T
OH
CS
D
OUT
Read Cycle 3
(Output Enable Controlled)
Address
OE
CS
D
OUT
T
ACS
T
CLZ
RC
T
T
AA
AOE
T
TOLZ
TACS
CLZT
T
CHZ
TOH
TOHZ
CHZ
T
Publication Release Date: April 1997
- 5 - Revision A11
Timing Waveforms, continued
Write Cycle 1
Address
OE
CS
WE
DOUT
DIN
W24257
T
WC
T
WR
T
CW
T
AW
T
T
AS
T
OHZ
(1, 4)
WP
T
DW
T
DH
Write Cycle 2
(OE = VIL Fixed)
T
WC
Address
T
T
CW
CS
AWT
WE
D
OUT
DIN
T
AS
T
WP
T
WHZ
(1, 4)
Notes:
1. During this period, I/O pins are in the output state, so input signals of opposite phase to the outputs should not be applied.
2. The data output from DOUT are the same as the data written to DIN during the write cycle.
3. DOUT provides the read data for the next address.
4. Transition is measured ±500 mV from steady state with CL = 5 pF. This parameter is guaranteed but not 100% tested.
WR
T
OH
T
OW
DW
TDH
T
(2)(3)
- 6 -
W24257
CS
CS
DATA RETENTION CHARACTERISTICS
(TA = 0 to 70° C)
PARAMETERSYM.TEST CONDITIONSMIN. TYP. MAX. UNIT
VDD for Data RetentionVDR
Data Retention CurrentIDDDR
≥ VDD -0.2V
≥ VDD -0.2V
VDD = 3VL--50
Chip Deselect to Data Retention Time TCDRSee data retention0--nS
Operation Recovery TimeTRwaveformTRC*--nS
TRC* = Read Cycle Time
DATA RETENTION WAVEFORM
DATA RETENTION MODE
V
CS
DD
4.5V
T
CDR
VIHV
CS1
>
V
DR
2V
=
>
V
DD
=
-0.2V
4.5V
T
R
IH
2.0--V
LL--20
µA
µA
ORDERING INFORMATION
PART NO.ACCESS
TIME (nS)
W24257-70LL708050600 mil DIP
W24257-70L7080100600 mil DIP
W24257-10L10070100600 mil DIP
W24257S-70LL708050330 mil SOP
W24257S-70L7080100330 mil SOP
W24257S-10L10070100330 mil SOP
W24257K-70LL708050300 mil Skinny
W24257K-70L7080100300 mil Skinny
W24257K-10L10070100300 mil Skinny
W24257J-70LL708050300 mil SOJ
W24257J-70L7080100300 mil SOJ
W24257J-10L10070100300 mil SOJ
Notes:
1. Winbond reserves the right to make changes to its products without prior notice.
2. Purchasers are responsible for performing appropriate quality assurance testing on products intended for use in
applications where personal injury might occur as a consequence of product failure.