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参数资料
| 型号： | M48T512YPM |
| 厂商： | 意法半导体 |
| 英文描述： | 3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| 中文描述： | 3.3 - 5V的4兆位的SRAM 512KB的x8计时器 |
| 文件页数： | 10/14页 |
| 文件大小： | 104K |
| 代理商： | M48T512YPM |
M48T512Y, M48T512V
10/14
Assuming that the oscillator is running at exactly
32,768Hz, each of the 31 increments in the Cali-
bration byte would represent +10.7 or –5.35 sec-
onds per month which corresponds to a total range
of +5.5 or –2.75 minutes per month. Figure 10 il-
lustrates a TIMEKEEPER calibration waveform.
One method for ascertaining how much calibration
a given M48T512Y/V may require involves setting
the clock, letting it run for a month and comparing
it to a known accurate reference and recording de-
viation over a fixed period of time.
Calibration values, including the number of sec-
onds lost or gained in a given period, can be found
in STMicroelectronics Application Note: TIME-
KEEPER CALIBRATION. This allows the designer
to give the end user the ability to calibrate the
clock as the environment requires, even if the final
product is packaged in a non-user serviceable en-
closure. The designer could provide a simple utility
that accesses the Calibration bits. For more infor-
mation on calibration, see Application Note (TIME-
KEEPER CALIBRATION) on the ST Web Site.
POWER SUPPLY DECOUPLING
and UNDERSHOOT PROTECTION
Note:
I
CC
transients, including those produced by
output switching, can produce voltage fluctua-
tions, 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 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 recom-
mended 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
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 con-
nected to V
CC
, anode to V
SS
). (Schottky diode
1N5817 is recommended for through hole and
MBRS120T3 is recommended for surface mount).
Figure 9. Chip Enable Controlled, Write AC Waveforms
AI02387
tAVAV
tEHAX
tDVWH
A0-A18
E
W
DQ0-DQ7
VALID
tAVEH
tAVEL
tAVWL
tELEH
tWHDX
DATA INPUT
相关PDF资料 |
PDF描述 |
|---|---|
| M48T513VPM | 3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513V-70CS1 | 3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513V-70PM1 | 3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513V-85CS1 | 3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513V-85PM1 | 3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
相关代理商/技术参数 |
参数描述 |
|---|---|
| M48T513V | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513V-70CS1 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513V-70PM1 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513V-85CS1 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513V-85PM1 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
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