CONNECTION for a SNAPHAT TOP which
CONTAINS the BATTERY and CRYSTAL
■ PIN and FUNCTION COMPATIBLE with
JEDEC STANDARD 32K x8 SRAMs
SNAPHAT (SH)
Battery
28
28
1
SOH28 (MH)
Figure 1. Logic Diagram
V
CC
1
PCDIP28 (PC)
Battery CAPHAT
DESCRIPTION
®
The M48Z35AY/35AV ZEROP OWER
RAM is a
32 Kbit x8 non-volatile static RAM that integrates
power-fail deselect circuitry and battery control
logic on a single die. The monolithi c chip is available in two special packages to provide a highly integrated battery backed-up memory solution.
Table 1. Signal Names
A0-A14Address Inputs
DQ0-DQ7Data Inputs / Outputs
E
G
W
V
V
CC
SS
Chip Enable
Output Enable
Write Enable
Supply Voltage
Ground
A0-A14
W
15
M48Z35AY
M48Z35AV
E
G
V
SS
8
DQ0-DQ7
AI02781B
1/16April 2000
Page 2
M48Z35AY, M48Z35AV
Figure 2A. DIP Pin Connections
A14V
1
A12
2
3
A7
4
A6
5
A5
6
A4
7
A3
A2
A1
A0
DQ0
M48Z35AY
M48Z35AV
8
9
10
11
12
13
DQ2
14
SS
Table 2. Absolute Maximum Ratings
SymbolParameterValueUnit
T
A
T
STG
(2)
T
SLD
V
IO
V
CC
I
O
P
D
Note: 1. Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress
rating only and functional operation of the device at these or a ny other conditions above those indicat ed in the operational section
of this spec ification is not im plied. Exposure t o the abso lute max imum rat ing cond itions for extende d period s of tim e may affe ct
reliability.
2. Soldering temperature not to exceed 260°C for 10 seconds (total thermal budget not to exceed 150°C for longer than 30 seconds).
CAUTION: Negative undershoots below –0.3V are not allowed on any pin whil e i n th e Battery Back-up mode.
CAUTION: Do NOT wave solder SOIC to avoid damaging SNAPHAT sockets.
Ambient Operating TemperatureGrade 1
Storage Temperature (VCC Off)SNAPHAT
Lead Solder Temperature for 10 seconds260°C
Input or Output Voltages–0.3 to 7V
Supply Voltage–0.3 to 7V
Output Current20mA
Power Dissipation1W
Note: 1. X = VIH or VIL; VSO = Battery Back-up Swit ch ov er Volta ge.
2. See T able 7 for deta ils .
4.5V to 5.5V
3.0V to 3.6V
V
to V
SO
Figure 3. Block Diagram
LITHIUM
CELL
VOLTAGE SENSE
AND
SWITCHING
CIRCUITRY
XXHigh ZStandby
X
V
IL
V
IH
POWER
V
PFD
V
IL
V
IH
V
IH
32K x 8
SRAM ARRAY
D
IN
D
OUT
High ZActive
Active
Active
A0-A14
DQ0-DQ7
E
W
V
CC
The M48Z35AY/35AV is a non-volatile pin and
function equivalent to any JEDEC standard 32K x8
SRAM. It also easily fits into many ROM, EPROM,
and EEPROM sockets, providing the non-volatility
of PROMs without any requirement for special
write timing or limitations on the number o f writes
that can be performed. The 28 pin 600mil DIP
CAPHAT™ houses the M48Z35AY/35AV silicon
with a long life lithium button cell in a single pa ckage.
G
V
SS
AI01619B
The 28 pin 330mil SOIC provides sockets with
gold plated contacts at both ends for direct connection to a separate SNAPHAT housing cont aining the battery. The unique design allows the
SNAPHAT battery p acka ge t o b e m ount ed o n t op
of the SOIC package after the c ompletion of the
surface mount process. Insertion of the SNAPHAT
housing after reflow prevents potential battery
damage due to the high temperatures required for
device surface-mounting. The SNAPH AT housing
is keyed to prevent reverse insertion.
3/16
Page 4
M48Z35AY, M48Z35AV
Table 4. AC Measurement Conditions
Input Rise and Fall Times≤ 5ns
Input Pulse Voltages0 to 3V
Input and Output Timing Ref. Voltages1.5V
Note that Output Hi-Z is defined as the point where data is no longer
driven.
The SOIC and battery packages are shipped separately in plastic anti-static tubes or in Tape & Reel
form.
For the 28 lead SOIC, the battery package (i.e.
SNAPHAT) part number is "M4Z28-BR00SH1".
The M48Z35AY/35AV also has its own Power-fail
Detect circuit. The control circuitry constantly monitors the single 5V supply for an out of tolerance
condition. When V
is out of tolerance, the circuit
CC
write protects the S RAM, p roviding a high degree
of data security in the midst of unpredictable s ystem operation brought on by low V
CC
. As V
CC
falls
below approximately 3V, the control circuitry connects the battery which maintains data until valid
power returns.
READ MODE
The M48Z35AY/35AV i s in th e Read M ode whenever W
(Write Enable) is high, E (Ch ip Enable) is
low. The device architecture allows ripple-through
access of data from eight of 264,144 locat ions in
the static storage array. Thus, the unique address
specified by the 15 Address Inputs defines which
one of the 32,768 bytes of data is to be accessed.
Valid data will be available at the Data I/O pins
within Address Access time (t
) after the last
AVQV
address input signal is stable, providing that the E
and G access times are also satisfied. If the E and
G
access times are not met, valid data will be
available after the latter of the Chip Enable Access
time (t
(t
GLQV
) or Output Enable Access time
ELQV
).
The state of the eight three-s tate Da ta I/O si gnals
is controlled by E
and G. If the outputs are activat-
Figure 4. AC Testing Load Circuit
DEVICE
UNDER
TEST
CL includes JIG capacitance
ed before t
, the data lines will be driven to an
AVQV
indeterminate state until t
puts are changed while E
645Ω
CL = 100pF or
5pF
. If the Ad dres s In-
AVQV
and G remain active,
1.75V
AI03211
output dat a will rem ain v alid for Outp ut Dat a Hold
time (t
) but will go indeterminate until the next
AXQX
Addr e ss Access.
WRITE MODE
The M48Z35AY/35A V is in the Write Mode whenever W
enced from the latter occurring falling edge of W
E
of W
throughout the cycle. E
a minimum of t
and E are low. The start of a write is refer-
or
. A write is terminated by the earlier rising edge
or E. The addresses must be held valid
or W must return high for
from Chip Enable or t
EHAX
WHAX
from Write Enable prior to the initiation of another
read or write cycle. Data-in must be valid t
prior to the end of write and remain valid for t
DVWH
WHDX
afterward. G should be kept hig h during write cycles to avoid bus contention; although, if the output
bus has been activated by a low on E
will disable the outputs t
on W
WLQZ
and G, a low
after W falls.
4/16
Page 5
M48Z35AY, M48Z35AV
Table 5. Capacitance
(T
= 25 °C)
A
(1, 2)
SymbolParameterTest ConditionMinMaxUnit
C
C
IO
Note: 1. Effective capacitan ce measured wi th power su pply at 5V.
2. Sampled only, not 100% tested.
3. Outputs deselect ed.
Input Capacitance
IN
(3)
Input / Output Capacitance
V
V
OUT
IN
= 0V
= 0V
10pF
10pF
Table 6. DC Characteristics
(T
= 0 to 70 °C or –40 to 85 °C; VCC = 4.5V to 5.5V or 3.0v to 3.6V)
A
SymbolParameterTest ConditionMinMaxUnit
(1)
I
LI
I
LO
I
CC
I
CC1
I
CC2
V
IL
V
IH
V
OL
V
OH
Note: 1. Outputs deselected .
2. Negativ e s p i k e s of –1V allowed for up t o 10 ns once per cycle.
Input Leakage Current
(1)
Output Leakage Current
Supply CurrentOutputs open50mA
Supply Current (Standby) TTL
Supply Current (Standby) CMOS
(2)
Input Low Voltage–0.30.8V
Input High Voltage2.2
Output Low Voltage
Output High Voltage
0V ≤ V
IN
0V ≤ V
OUT
E
= V
E
= VCC – 0.2V
I
= 2.1mA
OL
I
= –1mA
OH
≤ V
≤ V
IH
CC
CC
±1µA
±5µA
3mA
3mA
V
+ 0.3
CC
0.4V
2.4V
V
Table 7. Power Down/Up Trip Points DC Characteristics
(1)
(TA = 0 to 70 °C or –40 to 85 °C)
SymbolParameterMinTypMaxUnit
V
PFD
V
PFD
V
SO
V
SO
t
DR
Note: 1. All voltages referenced to VSS.
2. At 25 ° C.
Power-fail Deselect Voltage (M48Z35AY)4.24.354.5V
Power-fail Deselect Voltage (M48Z35AV)2.72.93.0V
Battery Back-up Switchover Voltage (M48Z35AY)3.0V
V
Battery Back-up Switchover Voltage (M48Z35AV)
(2)
Expected Data Retention Time10YEARS
PFD
– 100mV
V
5/16
Page 6
M48Z35AY, M48Z35AV
Table 8. Power Down/Up AC Characteristics
(T
= 0 to 70 °C or –40 to 85 °C)
A
SymbolParameterMinMaxUnit
t
PD
t
F
t
FB
t
R
t
RB
t
REC
Note: 1. V
2. V
3. t
E or W at VIH before Power Down
(1)
V
(max) to V
PFD
(2)
V
(3)
PFD
es V
PFD
PFD
(min) = 20ms for industri al tempera ture grade (6) device.
REC
(min) to VSS VCC Fall Time
PFD
V
(min) to V
PFD
VSS to V
V
PFD
(max) to V
(min).
(min) to VSS fall time of less than tFB may cause corruption of RA M data.
(min) VCC Rise Time
PFD
(max) to Inputs Recognized
(min) fall time of less than tF may result in deselection/write protection not occurring until 200µs after VCC pass-
PFD
(min) VCC Fall Time
PFD
(max) VCC Rise Time
PFD
Figure 5. Power Down/Up Mode AC Waveforms
V
CC
V
(max)
PFD
V
(min)
PFD
VSO
tF
tPD
INPUTS
tFB
tDR
tRB
DON'T CARE
0µs
300µs
10µs
10µs
1µs
40200ms
tR
tREC
RECOGNIZEDRECOGNIZED
6/16
OUTPUTS
VALIDVALID
(PER CONTROL INPUT)
HIGH-Z
(PER CONTROL INPUT)
AI01168C
Page 7
Table 9. Read Mode AC Characteristics
(T
= 0 to 70 °C or –40 to 85 °C; VCC = 4.5V to 5.5V or 3.0V to 3.6V)
A
M48Z35AYM48Z35AV
M48Z35AY, M48Z35AV
SymbolParameter
t
AVAV
t
AVQV
t
ELQV
t
GLQV
t
ELQX
t
GLQX
t
EHQZ
t
GHQZ
t
AXQX
Note: 1. CL = 100pF (see Figure 4).
2. C
Read Cycle Time70100ns
(1)
Address Valid to Output Valid70100ns
(1)
Chip Enable Low to Output Valid70100ns
(1)
Output Enable Low to Output Valid3550ns
(2)
Chip Enable Low to Output Transition510ns
(2)
Output Enable Low to Output Transition55ns
(2)
Chip Enable High to Output Hi-Z2550ns
(2)
Output Enable High to Output Hi-Z2540ns
(1)
Address Transition to Output Transition1010ns
= 5pF (see Figure 4).
L
Figure 6. Read Mode AC Waveforms.
Unit-70-100
MinMaxMinMax
A0-A14
E
G
DQ0-DQ7
Note: Write Enable (W
) = High.
tAVAV
VALID
tAVQVtAXQX
tELQV
tELQX
tGLQX
tGLQV
tGHQZ
VALID
tEHQZ
AI00925
7/16
Page 8
M48Z35AY, M48Z35AV
Table 10. Write Mode AC Characteristics
(T
= 0 to 70 °C or –40 to 85 °C; VCC = 4.5V to 5.5V or 3.0V to 3.6V)
A
M48Z35AYM48Z35AV
SymbolParameter
t
AVAV
t
AVWL
t
AVEL
t
WLWH
t
ELEH
t
WHAX
t
EHAX
t
DVWH
t
DVEH
t
WHDX
t
EHDX
(1, 2)
t
WLQZ
t
AVWH
t
AVEH
(1, 2)
t
WHQX
Note: 1. CL = 5pF (see Figure 4).
2. If E
Write Cycle Time70100ns
Address Valid to Write Enable Low00ns
Address Valid to Chip Enable Low00ns
Write Enable Pulse Width5080ns
Chip Enable Low to Chip Enable High5580ns
Write Enable High to Address Transition010ns
Chip Enable High to Address Transition010ns
Input Valid to Write Enable High3050ns
Input Valid to Chip Enable High3050ns
Write Enable High to Input Transition55ns
Chip Enable High to Input Transition55ns
Write Enable Low to Output Hi-Z2550ns
Address Valid to Write Enable High6080ns
Address Valid to Chip Enable High6080ns
Write Enable High to Output Transition510ns
goes low simultaneously with W going low, the outputs rem ai n in the high impedance stat e.
Unit-70-100
MinMaxMinMax
DATA RETENTION MODE
With valid V
applied, the M48Z35AY/ 35AV op-
CC
erates as a conventional BYTEWIDE™ static
RAM. Should the supply voltage decay, the RAM
will automatically power-fail deselect, write protecting itself when V
(min) window. All outputs become high im-
V
PFD
falls within the V
CC
PFD
(max),
pedance, and all inputs are treated as "don't care."
Note: A power failure during a write cycle may
corrupt data at the currently a ddressed location,
but does not jeopardize the rest of the RAM's content. At voltages below V
(min), the user can be
PFD
assured the memory will be i n a write protected
state, provided the V
fall time is not less than tF.
CC
The M48Z35AY/35AV may respond to transient
noise spikes on V
8/16
that reach into the deselect
CC
window during the time the device is sampling
. Therefore, decoupling of the power supply
V
CC
lines is recommended.
When V
drops below VSO, the control circuit
CC
switches power to the internal battery which preserves data. The internal button cell will maintain
data in the M48Z35AY/35AV for an accumulated
period of at least 10 years (at 25°C) when V
less than V
As system power returns and V
, the battery is disconn ected, and the power
V
SO
supply is switched to external V
tion continues until V
t
(min). Normal RAM operation can resume
REC
after V
t
REC
.
SO
exceeds V
CC
reaches V
CC
PFD
CC
. Write protec-
CC
(max).
rises above
(min) plus
PFD
CC
is
Page 9
Figure 7. Write Enable Controlled, Write AC Waveform
tAVAV
M48Z35AY, M48Z35AV
A0-A14
tAVEL
E
tAVWL
W
tWLQZ
DQ0-DQ7
VALID
tAVWH
tWLWH
Figure 8. Chip Enable Controlled, Write AC Waveforms
tAVAV
tDVWH
tWHAX
tWHQX
tWHDX
DATA INPUT
AI00926
A0-A14
E
W
DQ0-DQ7
tAVEL
tAVWL
VALID
tAVEH
tELEH
DATA INPUT
tDVEH
tEHAX
tEHDX
AI00927
9/16
Page 10
M48Z35AY, M48Z35AV
Figure 9. Checking the BOK Flag Status
POWER-UP
READ DATA
AT ANY ADDRESS
WRITE DATA
COMPLEMENT BACK
TO SAME ADDRESS
READ DATA
AT SAME
ADDRESS AGAIN
IS DATA
COMPLEMENT
OF FIRST
(BATTERY OK)
WRITE ORIGINAL
DATA BACK TO
SAME ADDRESS
CONTINUE
READ?
YES
NO
(BATTERY LOW)
NOTIFY SYSTEM
OF LOW BATTERY
(DATA MAY BE
CORRUPTED)
AI00607
Also, as VCC rises, the battery voltage is checked.
If the voltage is less than approxima tely 2.5V, an
internal Battery Not OK (BOK
BOK
flag can be checked after power up. If the
BOK
flag is set, the first write at tempted will be
) flag will be set. The
blocked. The flag is automatically cleared after the
first write, and normal RAM operation resumes.
Figure 9 illustrates how a BOK
check routine could
be structured.
For more information on Battery Storage Life refer
to the Application Note AN1012.
Figure 10. Supply Voltage Protection
V
CC
V
CC
0.1µFDEVICE
V
SS
AI02169
POWER SUPPLY DECOUPLING and
UNDERSHOOT PROTECTION
I
transients, including those produced by output
CC
switching, can produce voltage fluctuations, resulting in spikes on the V
bus. These transients
CC
can be reduced if capacitors are used to store energy, which stabilizes the V
bus. The energy
CC
stored in the bypass capacitors will be released as
low going spikes are generated or energy will be
absorbed when overshoots occur. A ceramic by-
pass capacitor value of 0.1µF (as shown in Figure
10) is recommended in order to provide the needed filtering.
In addition to transients that are caused by normal
SRAM operation, power cycling can generate negative voltage spikes on VCC that drive it to values
below V
by as much as one Volt. These nega-
SS
tive spikes can cause data corruption in the SRAM
while in battery backup mode. To protect from
these voltage spikes, it is recommended to connect a schottky diode from V
connected to V
, anode to VSS). Schottky diode
CC
to VSS (cathode
CC
1N5817 is recommended for through hole and
MBRS120T3 is recommended for surface mount.
10/16
Page 11
M48Z35AY, M48Z35AV
Table 11. Ordering Information Scheme
Example: M48Z35AY-70 MH 1 TR
Supply Voltage and Write Protect Voltage
35AY = V
35AV = V
Speed
-70 = 70ns (M48Z35AY)
-100 = 100ns (M48Z35AV)
Package
PC = PCDIP28
(1)
MH
Temperature Range
1 = 0 to 70 °C
(2)
6
= –40 to 85 °C
Shipping Method for SOIC
blank = Tubes
TR = Tape & Reel
= 4.5V to 5.5V; V
CC
= 3.0V to 3.6V; V
CC
= SOH28
= 4.2V to 4.5V
PFD
= 2.7V to 3.0V
PFD
Note: 1. The SOIC pa ck age (SOH28) requires the battery packa ge (SNAPHAT) which is orde red separat el y under the part n um ber
"M4Zxx-BR00SH1" in plastic tube or "M4Zxx-BR00SH1TR" in Tape & Reel form.
2. Industrial temperature grade available in SOIC package (SOH28) only.
Caution: Do not place t he SNAP HAT battery package " M4Z28-BR00SH1" i n con ductive foam s ince wi ll drain the lithium button-c ell bat tery.
For a list of available options (Speed, Pac kage, etc...) or for furthe r information on any aspect of this device, please contact the STMicroelectronics Sales Office nearest to you.
Table 12. Revision History
DateRevision Details
September 1999 First Issue
04/20/00SH and SH28 packages for 2-pin and 2-socket removed
Figure 14. SH - SNAPHAT Housing for 120 mAh Battery, Package Outline
A1
A
eA
B
D
E
Drawing is not to scale.
A2
A3
L
eB
SHZP-A
15/16
Page 16
M48Z35AY, M48Z35AV
Information furnishe d is bel i eved to be accurate and reliable. However, STM icroelectro ni cs assumes no responsibility for t he consequ ences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implic ation or oth erwise under any patent or patent rights of S T M i croelectr onics. Spec i fications mentioned in this publ ic at ion ar e subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems wi thout express written ap proval of STMicroelectro nics.
The ST log o i s registered trademark of STM i croelect ronics
2000 STMicroel e ctronics - All Ri ghts Reserved
All other names are the property of their respec tive owners.
Australi a - Brazil - Chin a - Finland - France - Germ any - Hong Kong - India - Italy - Japan - Malaysi a - M al ta - Morocc o -
Singapor e - Spain - Swede n - Switzerla nd - United Kingdom - U.S.A .
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http://www.st.com
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