M48Z35, M48Z35Y Operating modes
Doc ID 2608 Rev 10 13/24
2.4 V
CC
noise and negative going transients
I
CC
transients, including those produced by output switching, can produce voltage
fluctuations, resulting in spikes on the V
CC
bus. These transients can be reduced if
capacitors are used to store energy which stabilizes the V
CC
bus. The energy stored in the
bypass capacitors will be released as low going spikes are generated or energy will be
absorbed when overshoots occur. A ceramic bypass capacitor value of 0.1 µF (see Figure 9)
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 V
CC
that drive it to values below V
SS
by as much as
one volt. These negative spikes can cause data corruption in the SRAM while in battery
backup mode. To protect from these voltage spikes, ST recommends connecting a Schottky
diode from V
CC
to V
SS
(cathode connected to V
CC
, anode to V
SS
). (Schottky diode 1N5817
is recommended for through hole and MBRS120T3 is recommended for surface mount).
Figure 9. Supply voltage protection
AI02169
V
CC
0.1µF DEVICE
V
CC
V
SS
Maximum ratings M48Z35, M48Z35Y
14/24 Doc ID 2608 Rev 10
3 Maximum ratings
Stressing the device above the rating listed in the absolute maximum ratings table may
cause permanent damage to the device. These are stress ratings only and operation of the
device at these or any other conditions above those indicated in the operating sections of
this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
Table 7. Absolute maximum ratings
Caution: Negative undershoots below –0.3 V are not allowed on any pin while in the battery backup
mode.
Caution: Do NOT wave solder SOIC to avoid damaging SNAPHAT
®
sockets.
Symbol Parameter Value Unit
T
A
Ambient operating temperature 0 to 70 °C
T
STG
Storage temperature (V
CC
off, oscillator off)
SNAPHAT
®
top –40 to 85 °C
CAPHAT
®
DIP –40 to 85 °C
SOH28 –55 to 125 °C
T
SLD
(1)(2)
1. For DIP package, soldering temperature of the IC leads is to not exceed 260 °C for 10 seconds.
Furthermore, the devices shall not be exposed to IR reflow nor preheat cycles (as performed as part of
wave soldering). ST recommends the devices be hand-soldered or placed in sockets to avoid heat
damage to the batteries.
2. For SOH28 package, lead-free (Pb-free) lead finish: reflow at peak temperature of 260 °C (the time above
255 °C must not exceed 30 seconds).
Lead solder temperature for 10 seconds 260 °C
V
IO
Input or output voltages –0.3 to 7.0 V
V
CC
Supply voltage –0.3 to 7.0 V
I
O
Output current 20 mA
P
D
Power dissipation 1 W
M48Z35, M48Z35Y DC and AC parameters
Doc ID 2608 Rev 10 15/24
4 DC and AC parameters
This section summarizes the operating and measurement conditions, as well as the DC and
AC characteristics of the device. The parameters in the following DC and AC characteristic
tables are derived from tests performed under the measurement conditions listed in Ta bl e 8:
Operating and AC measurement conditions. Designers should check that the operating
conditions in their projects match the measurement conditions when using the quoted
parameters.
Table 8. Operating and AC measurement conditions
Note: Output Hi-Z is defined as the point where data is no longer driven.
Figure 10. AC measurement load circuit
Table 9. Capacitance
Parameter M48Z35 M48Z35Y Unit
Supply voltage (V
CC
) 4.75 to 5.5 4.5 to 5.5 V
Ambient operating temperature (T
A
) 0 to 70 0 to 70 °C
Load capacitance (C
L
) 100 100 pF
Input rise and fall times 5 5ns
Input pulse voltages 0 to 3 0 to 3 V
Input and output timing ref. voltages 1.5 1.5 V
Symbol Parameter
(1)(2)
1. Effective capacitance measured with power supply at 5 V. Sampled only, not 100% tested.
2. Outputs deselected.
Min Max Unit
C
IN
Input capacitance -10pF
C
IO
(3)
3. At 25 °C.
Input / output capacitance -10pF
AI03211
C
L
= 100pF or
5pF
C
L
includes JIG capacitance
645Ω
DEVICE
UNDER
TEST
1.75V

M48Z35Y-70MH1F

Mfr. #:
Manufacturer:
STMicroelectronics
Description:
NVRAM 256K (32Kx8) 70ns
Lifecycle:
New from this manufacturer.
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