Datasheet

Clock operation M48T201Y, M48T201V
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3.13 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 (as shown in
Figure 12) 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, STMicroelectronics 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 12. Supply voltage protection
AI00605
V
CC
0.1μF DEVICE
V
CC
V
SS