ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 1/12
PSRAM 2-Mbit (256K x 8)
Pseudo Static RAM
Features
•Advanced low-power architecture
•High speed: 55 ns, 70 ns
•Wide voltage range: 2.7V to 3.6V
•Typical active current: 1 mA @ f = 1 MHz
•Low standby power
•Automatic power-down when deselected
Functional Description
The M24L28256SA is a high-performance CMOS pseudo
static RAM (PSRAM) organized as 256K words by 8 bits.
Easy memory expansion is provided by an active LOW Chip
Enable( CE ) and active LOW Output Enable ( OE ).This
device has an automatic power-down feature that reduces
power consumption dramatically when deselected. Writing to
the device is accomplished by asserting Chip Enable ( CE )
and Write Enable ( WE ) inputs LOW .Data on the eight I/O
pins(I/O0 through I/O7) is then written into the location
specified on the address pins (A0 through A17).
Reading from the device is accomplished by asserting the
Chip Enable One ( CE ) and Output Enable ( OE ) inputs LOW
while forcing Write Enable ( WE ) HIGH. Under these
conditions, the contents of the memory location specified by
the address pins will appear on the I/O pins.
The eight input/output pins (I/O0 through I/O7) are placed in a
high-impedance state when the device is deselected ( CE
HIGH ), the outputs are disabled ( OE HIGH), or during write
operation ( CE LOW and WE LOW). See the Truth Table
for a complete description of read and write modes.
Logic Block Diagram
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 2/12
Pin Configuration[2, 3]
VFBGA
Top View
Product Portfolio
Power Dissipation
Operating ICC(mA)
VCC Range (V)
f = 1MHz f = fMAX
Standby ISB2(µA) Product
Min. Typ. Max.
Speed(ns)
Typ.[3] Max. Typ.[3] Max. Typ. [3] Max.
55 14 22
M24L28256SA 2.7 3.0 3.6
70
1 5
8 15
9 40
Notes:
2.NC “no connect”—not connected internally to the die.
3. Typical values are included for reference only and are not guaranteed or tested. Typical values are measured at VCC = VCC (typ)
and TA = 25°C.
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 3/12
Maximum Ratings
(Above which the useful life may be impaired. For user
guide-lines, not tested.)
Storage Temperature ...................................–65°C to +150°C
Ambient Temperature with
Power Applied ..............................................–55°C to +125°C
Supply Voltage to
Ground Potential . ............... ............ ...........−0.4V to 4.6V
DC Voltage Applied to Outputs
in High-Z State[4, 5, 6] .................................−0.4V to 3.7V
DC Input Voltage[4, 5, 6].................... .........−0.4V to 3.7V
Output Current into Outputs (LOW) ...............................20 mA
Static Discharge Voltage ........................................ >2001V
(per MIL-STD-883, Method 3015)
Latch-up Current ....................................................> 200 mA
Operating Range
Range Ambient
Temperature (TA) VCC
Extended −25°C to +85°C 2.7V to 3.6V
Industrial −40°C to +85°C 2.7V to 3.6V
Electrical Characteristics (Over the Operating Range)
-55 -70
Parameter Description Test Conditions Min. Typ
.[3] Max. Min. Typ.
[3] Max. Unit
VCC Supply Voltage 2.7 3.0 3.6 2.7 3.0 3.6 V
VOH Output HIGH
Voltage IOH = −0.1 mA VCC-
0.4
VCC-
0.4 V
VOL Output LOW
Voltage IOL = 0.1 mA 0.4 0.4 V
VIH Input HIGH
Voltage 0.8*
VCC VCC+
0.4
0.8*
VCC VCC
+0.4 V
VIL Input LOW Voltage -0.4 0.4 -0.4 0.4 V
IIX Input Leakage
Current GND ≤VIN ≤ V
CC -1 +1 -1 +1
µA
IOZ Output Leakage
Current
GND ≤ V
OUT ≤ V
CC , Output
Disable -1 +1 -1 +1
µA
f = fMAX = 1/tRC 14 22 8 15
ICC VCC Operating
Supply Current f = 1 MHz
VCC = 3.6V
IOUT = 0mA
CMOS levels
1 5 1 5
mA
ISB1
Automatic CE
Power-Down
Current
—CMOS Inputs
CE ≥ V
CC−0.2V,
VIN ≥ V
CC − 0.2V, VIN ≤ 0.2V,
f = fMAX (Address and Data Only),
f = 0
40 250 40 250 µA
ISB2
Automatic CE
Power-Down
Current
—CMOS Inputs
CE ≥ V
CC−0.2V,
VIN ≥ V
CC − 0.2V, VIN ≤ 0.2V,
f = 0, VCC = 3.6V
9 40 9 40 µA
Capacitance[7]
Parameter Description Test Conditions Max. Unit
CIN Input Capacitance 8 pF
COUT Output Capacitance
TA = 25°C, f = 1 MHz
VCC = VCC(typ) 8 pF
Thermal Resistance[7]
Parameter Description Test Conditions BGA Unit
ΘJA Thermal Resistance(Junction to Ambient) 55 °C/W
ΘJC Thermal Resistance (Junction to Case)
Test conditions follow standard test
methods and procedures for measuring
thermal impedance, per EIA/ JESD51. 17 °C/W
Notes:
4.VIH(MAX) = VCC + 0.5V for pulse durations less than 20 ns.
5.VIL(MIN) = –0.5V for pulse durations less than 20 ns.
6.Overshoot and undershoot specifications are characterized and are not 100% tested.
7.Tested initially and after design or process changes that may affect these parameters.
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 4/12
AC Test Loads and Waveforms
Parameters 3.0V (VCC) Unit
R1 22000 Ω
R2 22000 Ω
RTH 11000 Ω
VTH 1.50 V
Switching Characteristics Over the Operating Range [8]
-55 -70
Parameter Description
Min. Max. Min. Max.
Unit
Read Cycle
tRC Read Cycle Time 55[12] 70 ns
tAA Address to Data Valid 55 70 ns
tOHA Data Hold from Address Change 5 10 ns
tACE CE LOW 55 70
ns
tDOE OE LOW to Data Valid 25 35
ns
tLZOE OE LOW to Low Z[9, 10] 5 5
ns
tHZOE OE HIGH to High Z[9, 10] 25 25
ns
tLZCE CE LOW 2 5
ns
tHZCE CE HIGH 25 25
ns
tSK[12] Address Skew 0 10 ns
Write Cycle [11]
tWC Write Cycle Time 55 70 ns
tSCE CE LOW 45 55 ns
tAW Address Set-Up to Write End 45 55 ns
tHA Address Hold from Write End 0 0 ns
tSA Address Set-Up to Write Start 0 0 ns
tPWE WE Pulse Width 40 55 ns
tSD Data Set-Up to Write End 25 25 ns
tHD Data Hold from Write End 0 0 ns
tHZWE WE LOW to High-Z[9, 10] 25 25
ns
tLZWE WE HIGH to Low-Z[9, 10] 5 5
ns
Notes:
8. Test conditions assume signal transition time of 1V/ns or higher, timing reference levels of VCC(typ)/2, input pulse levels of 0V
to VCC(typ), and output loading of the specified IOL/IOH and 30-pF load capacitance
9. tHZOE, tHZCE, and tHZWE transitions are measured when the outputs enter a high-impedance state.
10. High-Z and Low-Z parameters are characterized and are not 100% tested.
11. The internal write time of the memory is defined by the overlap of WE , CE = VIL, . All signals must be ACTIVE to initiate a
write and any of these signals can terminate a write by going INACTIVE. The data input set-up and hold timing should be
referenced to the edge of the signal that terminates write.
12. To achieve 55-ns performance, the read access should be CE controlled. In this case tACE is the critical parameter and tSK
is satisfied when the addresses are stable prior to chip enable going active. For the 70-ns cycle, the addresses must be
stable within 10 ns after the start of the read cycle.
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 5/12
Switching Waveforms
Read Cycle 1 (Address Transition Controlled)[12, 13, 14]
Read Cycle 2 (OE Controlled)[12, 14]
Notes:
13. Device is continuously selected. OE and CE = VIL.
14. WE is HIGH for Read Cycle.
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 6/12
Switching Waveforms (continued)
Write Cycle 1 (WE Controlled)[10,11, 15, 16, 17]
Write Cycle 2 (CE Controlled) [9, 10, 15, 16, 17]
Notes:
15.Data I/O is high impedance if OE ≥ V
IH.
16. If Chip Enables go INACTIVE simultaneously with WE =HIGH, the output remains in a high-impedance state.
17.During the DON’T CARE period in the DATA I/O waveform, the I/Os are in output state and input signals should not be applied.
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 7/12
Switching Waveforms (continued)
Write Cycle 3 (WE Controlled, OE LOW)[16, 17]
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 8/12
Avoid Timing
ESMT Pseudo SRAM has a timing which is not supported at read operation, If your system has multiple invalid address signal
shorter than tRC during over 15μs at read operation shown as in Abnormal Timing, it requires a normal read timing at leat during
15μs shown as in Avoidable timing 1 or toggle CE to high (≧tRC) one time at least shown as in Avoidable Timing 2.
Abnormal Timing
Avoidable Timing 1
Avoidable Timing 2
CE
≧15μs
WE
Address
＜ tRC
CE
≧15μs
WE
Address
t≧RC
CE
≧15μs
WE
Address
＜ tRC
t≧RC
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 9/12
Truth Table[18]
CE OE WE I/O0-I/O7 Mode Power
H X X High Z Power-Down Standby (ISB)
X X X High Z Power-Down Standby (ISB)
L L H Data Out Read Active (ICC)
L X L Data In Write Active (ICC)
L H H High Z Selected, Outputs Disabled Active (ICC)
Ordering Information
Speed (ns) Ordering Code Package Type Operating Range
55 M24L28256SA-55BEG 36-Lead VFBGA (6 x 8 x 1 mm) (Pb-free) Extended
70 M24L28256SA-70BEG 36-Lead VFBGA (6 x 8 x 1 mm) (Pb-free) Extended
55 M24L28256SA-55BIG 36-Lead VFBGA (6 x 8 x 1 mm) (Pb-free) Industrial
70 M24L28256SA-70BIG 36-Lead VFBGA (6 x 8 x 1 mm) (Pb-free) Industrial
Note:
18.H = Logic HIGH, L = Logic LOW, X = Don’t Care.
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 10/12
Package Diagrams
36-Lead VFBGA (6 x 8 x 1 mm) BV36A
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 11/12
Revision History
Revision Date Description
1.0 2007.07.19 Original
1.1 2008.07.04
1. Move Revision History to the last
2. Modify voltage range 2.7V~3.3V to 2.7V~3.6V
3.Correct type error for Extended Temperature (-40~85°C
=> -25~85°C)
4. Add Industrial grade
5. Add Avoid timing
ESMT
M24L28256SA
Elite Semiconductor Memory Technology Inc. Publication Date : Jul. 2008
Revision : 1.1 12/12
Important Notice
All rights reserved.
No part of this document may be reproduced or duplicated in any form or by
any means without the prior permission of ESMT.
The contents contained in this document are believed to be accurate at the
time of publication. ESMT assumes no responsibility for any error in this
document, and reserves the right to change the products or specification in
this document without notice.
The information contained herein is presented only as a guide or examples for
the application of our products. No responsibility is assumed by ESMT for any
infringement of patents, copyrights, or other intellectual property rights of third
parties which may result from its use. No license, either express , implied or
otherwise, is granted under any patents, copyrights or other intellectual
property rights of ESMT or others.
Any semiconductor devices may have inherently a certain rate of failure. To
minimize risks associated with customer's application, adequate design and
operating safeguards against injury, damage, or loss from such failure, should
be provided by the customer when making application designs.
ESMT's products are not authorized for use in critical applications such as,
but not limited to, life support devices or system, where failure or abnormal
operation may directly affect human lives or cause physical injury or property
damage. If products described here are to be used for such kinds of
application, purchaser must do its own quality assurance testing appropriate
to such applications.
