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參數(shù)資料
| 型號： | tps3617 |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | BATTERY-BACKUP SUPERVISOR FOR RAM RETENTION(TPS3617-50 為保持RAM提供電池監(jiān)控的監(jiān)控器) |
| 中文描述： | 電池備份的RAM保持（TPS3617監(jiān)管者50為保持內(nèi)存提供電池監(jiān)控的監(jiān)控器） |
| 文件頁數(shù)： | 5/15頁 |
| 文件大小： | 279K |
| 代理商： | TPS3617 |
SLVS339B
–
DECEMBER 2000
–
REVISED DECEMBER 2002
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
detailed description
battery freshness seal
The battery freshness seal of the TPS3617 family disconnects the backup battery from the internal circuitry until
it is needed. This ensures that the backup battery connected to V
BAT
should be fresh when the final product is
put to use. The following steps explain how to enable the freshness seal mode:
1. Connect V
BAT
(V
BAT
>
V
BAT(min)
2. Ground PFO
3. Connect PFI to V
DD
(PFI = V
DD
)
4. Connect V
DD
to power supply (V
DD
>
V
IT
) and keep connected for 5 ms < t < 35 ms
The battery freshness seal mode is disabled by the positive-going edge of RESET when V
DD
is applied.
power-fail comparator (PFI and PFO)
An additional comparator monitors voltages other than the nominal supply voltage. The power-fail-input (PFI)
can be compared with an internal voltage reference of 1.15 V. If the input voltage falls below the power-fail
threshold (V
(PFI)
) of 1.15 V typical, the power-fail output (PFO) goes low. If it goes above V
(PFI)
plus about 12-mV
hysteresis, the output returns to high. By connecting two external resistors it is possible to supervise any
voltages above V
(PFI)
. The sum of both resistors should be about 1 M
, to minimize power consumption and
also to ensure that the current in the PFI pin can be neglected compared with the current through the resistor
network. The tolerance of the external resistors should be not more than 1% to ensure minimal variation of the
sensed voltage. If the power-fail comparator is unused, connect PFI to ground and leave the PFO
unconnected.
watchdog
In a microprocessor- or DSP-based system, it is not only important to supervise the supply voltage, it is also
important to ensure correct program execution. The task of a watchdog is to ensure that the program is not
stalled in an indefinite loop. The microprocessor, microcontroller, or DSP has to toggle the watchdog input within
0.8 s typically, to avoid a time out from occurring. Either a low-to-high or a high-to-low transition resets the
internal watchdog timer. If the input is unconnected, the watchdog is disabled and should be retriggered
internally.
saving current while using the watchdog
The watchdog input is internally driven low during the first 7/8 of the watchdog time-out period, then momentarily
pulses high, resetting the watchdog counter. For minimum watchdog input current (minimum overall power
consumption), leave WDI low for the majority of the watchdog time-out period, pulsing it low-high-low once
within 7/8 of the watchdog time-out period to reset the watchdog timer. If instead, WDI is externally driven high
for the majority of the time-out period, a current of e.g. 5.0 V/40 k
≈
125
μ
A can flow into WDI.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| TPS3619 | BACKUP-BATTERY SUPERVISORS FOR RAM RETENTION(用于RAM數(shù)據(jù)保持的后備電源監(jiān)控器) |
| TPS3705 | Processor Supervisory Circuits With Power-Fail(帶電源故障監(jiān)視處理機監(jiān)控電路) |
| TPS3707 | Processor Supervisory Circuits With Power-Fail(帶電源故障監(jiān)視處理機監(jiān)控電路) |
| tps3800(中文) | ULTRA SMALL SUPPLY VOLTAGE(超低電源電壓監(jiān)控器) |
| TPS3823(中文) | Processor Supervisory Circuits(處理器監(jiān)控電路) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TPS3617-50 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Battery-Backup Supervisors for RAM Retention |
| TPS3617-50DGK | 功能描述:監(jiān)控電路 Battery-Backup for RAM Retention RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| TPS3617-50DGK | 制造商:Texas Instruments 功能描述:BATTERY-BACKUP SVS FOR RAM RETEN |
| TPS3617-50DGKG4 | 功能描述:監(jiān)控電路 Battery-Backup for RAM Retention RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| TPS3617-50DGKR | 功能描述:監(jiān)控電路 Battery-Backup for RAM Retention RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
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