m48t212a STMicroelectronics, m48t212a Datasheet - Page 17

• Manufacturer Part Number: m48t212a
• Description: 3.3v Timekeeper Controller
• Manufacturer: STMicroelectronics

POWER SUPPLY DECOUPLING
AND UNDERSHOOT PROTECTION
Note: I
output switching, can produce voltage fluctua-
tions, resulting in spikes on the V
transients can be reduced if capacitors are used to
store energy, which stabilizes the V
energy stored in the bypass capacitors will be re-
leased as low going spikes are generated or ener-
gy will be absorbed when overshoots occur.
A ceramic bypass capacitor value of 0.1µF is rec-
ommended in order to provide the needed filtering.
In addition to transients that are caused by normal
SRAM operation, power cycling can generate neg-
ative voltage spikes on V
below V
spikes can cause data corruption in the SRAM
while in battery backup mode.
To protect from these voltage spikes, ST recom-
mends connecting a schottky diode from V
V
(Schottky diode 1N5817 is recommended for
through hole and MBRS120T3 is recommended
for surface mount).
SS
(cathode connected to V
CC
SS
transients, including those produced by
by as much as one volt. These negative
CC
that drive it to values
CC
, anode to V
CC
CC
bus. These
bus. The
CC
SS
to
).
Figure 13. Supply Voltage Protection
V CC
0.1 F
V CC
V SS
DEVICE
M48T212A
AI02169
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