參數(shù)資料
型號(hào)： M48T513V-70CS1
廠商： STMICROELECTRONICS
元件分類： 時(shí)鐘/數(shù)據(jù)恢復(fù)及定時(shí)提取
英文描述： 0 TIMER(S), REAL TIME CLOCK, PDSO32
封裝： 10 X 20 MM, PLASTIC, TSOP2-32
文件頁(yè)數(shù)： 10/30頁(yè)
文件大?。?/td> 161K
代理商： M48T513V-70CS1
M48T513Y, M48T513V
18/30
Battery Low Warning
The M48T513Y/V automatically performs battery
voltage monitoring upon power-up and at factory-
programmed time intervals of approximately 24
hours. The Battery Low (BL) bit, Bit D4 of Flags
Register 7FFF0h, will be asserted if the battery
voltage is found to be less than approximately
2.5V.
If a battery low is generated during a power-up se-
quence, this indicates that the battery is below ap-
proximately 2.5 volts and may not be able to
maintain data integrity in the SRAM. Data should
be considered suspect and verified as correct.
If a battery low indication is generated during the
24-hour interval check, this indicates that the bat-
tery is near end of life. However, data is not com-
promised due to the fact that a nominal VCC is
supplied.
The M48T513Y/V only monitors the battery when
a nominal VCC is applied to the device. Thus appli-
cations which require extensive durations in the
battery back-up mode should be powered-up peri-
odically (at least once every few months) in order
for this technique to be beneficial. Additionally, if a
battery low is indicated, data integrity should be
verified upon power-up via a checksum or other
technique.
Power-on Defaults
Upon application of power to the device, the fol-
lowing register bits are set to a ’0’ state: WDS,
BMB0-BMB4, RB0,RB1, AFE, ABE, W, R and FT.
POWER SUPPLY DECOUPLING AND UNDERSHOOT PROTECTION
ICC transients, including those produced by output
switching, can produce voltage fluctuations, re-
sulting in spikes on the VCC bus. These transients
can be reduced if capacitors are used to store en-
ergy, which stabilizes the VCC 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 by-
pass capacitor value of 0.1
F (see Figure 16) is
recommended in order to provide the needed fil-
tering. In addition to transients that are caused by
normal SRAM operation, power cycling can gener-
ate negative voltage spikes on VCC that drive it to
values below VSS 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 con-
necting a schottky diode from VCC to VSS (cathode
connected to VCC, anode to VSS). (Schottky diode
1N5817 is recommended for through hole and
MBRS120T3 is recommended for surface mount).
Figure 16. Supply Voltage Protection
AI02169
VCC
0.1
F
DEVICE
VCC
VSS
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
M48T513V-70PM1 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM
M48T513V-85CS1 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM
M48T513V-85PM1 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM
M48T513VPM 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM
M48T513VSH 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM
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