M48TMH1 STMICROELECTRONICS [STMicroelectronics], M48TMH1 Datasheet - Page 18

• Manufacturer Part Number: M48TMH1
• Description: 5V PC REAL TIME CLOCK
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M48T86
POWER SUPPLY DECOUPLING
and UNDERSHOOT PROTECTION
I
switching, can produce voltage fluctuations, re-
sulting in spikes on the V
can be reduced if capacitors are used to store en-
ergy, which stabilizes the V
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
14) is recommended in order to provide the need-
ed filtering.
In addition to transients that are caused by normal
SRAM operation, power cycling can generate neg-
ative voltage spikes on V
below V
tive spikes can cause data corruption in the SRAM
while in battery backup mode. To protect from
these voltage spikes, it is recommended to con-
nect a schottky diode from V
connected to V
1N5817 is recommended for through hole and
MBRS120T3 is recommended for surface mount.
18/23
CC
transients, including those produced by output
SS
by as much as one Volt. These nega-
CC
, anode to V
CC
CC
bus. These transients
that drive it to values
CC
CC
SS
bus. The energy
). Schottky diode
to V
SS
(cathode
Figure 14. Supply Voltage Protection
V CC
0.1 F
V CC
V SS
DEVICE
AI02169