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參數(shù)資料
| 型號(hào)： | NCV8141D2T |
| 廠(chǎng)商： | ON SEMICONDUCTOR |
| 元件分類(lèi)： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | 5.0 V, 500 mA Linear Regulator with ENABLE, RESET, and Watchdog |
| 中文描述： | 5 V FIXED POSITIVE REGULATOR, PSSO7 |
| 封裝： | D2PAK-7 |
| 文件頁(yè)數(shù)： | 8/12頁(yè) |
| 文件大小： | 89K |
| 代理商： | NCV8141D2T |
NCV8141
http://onsemi.com
8
APPLICATION NOTES
NCV8141 DESIGN EXAMPLE
The NCV8141 with its unique integration of linear
regulator and control features: RESET, ENABLE and
WATCHDOG, provides a single IC solution for a
microprocessor power supply. The reset delay, reset
duration and watchdog frequency limit are all determined by
a single capacitor. For a particular microprocessor the
overriding requirement is usually the reset delay (also
known as power on reset). The capacitor is chosen to meet
this requirement and the reset duration and watchdog
frequency follow.
The reset delay is given by:
tPOR(typ)
(4.75
105)CDELAY
Assume that the reset delay must be 200 ms minimum.
From the NCV8141 data sheet the reset delay has a
tolerance due to the regulator.
Assume the capacitor tolerance is
105
37%
10%.
tPOR(min)
(4.75
0.63)
CDELAY
0.9
CDELAY(min)
tPOR(min)
2.69
105
CDELAY(min)
0.743 F
Closest standard value is 0.82 F.
Minimum and maximum delays using 0.82 F are 220 ms
and 586 ms.
The duration of the reset pulse is given by:
TWDI(RESET)(typ)
This has a tolerance of
±
50% due to the IC, and
±
10% due
to the capacitor.
The duration of the reset pulse ranges from 3.69 ms to
13.5 ms.
The watchdog signal can be expressed as a frequency or
time. From a programmers point of view, time is more useful
since they must ensure that a watchdog signal is issued
consistently several times per second.
The watchdog time is given by:
(1.0
104)
CDELAY
tWDI
(1.3
105)CDELAY
There is a tolerance of
±
20% due to the NCV8141.
With a capacitor tolerance of
±
10%:
tWDI
(1.3
105)
1.2
1.1
CDelay
tWDI
141 ms (max)
tWDI
(1.3
105)
0.8
0.9
CDELAY
tWDI
76 ms (min)
The software must be written so that a watchdog signal
arrives at least every 76 ms.
Figure 9. WDI Signal for C
Delay
= 0.82 F using
NCV8141
Hz
ms
7
FAIL
13
76
141
PASS
ENERGY CONSERVATION AND SMART FEATURES
Energy conservation is another benefit of using a
regulator with integrated microprocessor control features.
Using the NCV8141 as indicated in Figure 10, the
microprocessor can control its own power down sequence.
The momentary contact switch quickly charges C1 through
R1.
When the voltage across C1 reaches 3.95 V ( the enable
threshold), the output switches on and V
OUT
rises to 5.0 V.
After a delay period determined by C
Delay
, a frequency
programmable reset pulse train is generated at the reset
output. The pulse train continues until the correct watchdog
signal appears at the WDI lead. C1 is now left to discharge
through the input impedance of the enable lead
(approximately 150 k ) and the enable signal disappears.
The output voltage remains at 5.0 V as long as the NCV8141
continues to receive the correct watchdog signal.
The microprocessor can power itself down by terminating
its watchdog signal. When the microprocessor finishes its
housekeeping or power down software routine, it stops
sending a watchdog signal. In response, the regulator
generates a reset signal and goes into a sleep mode where
V
OUT
drops to 0 V, shutting down the microprocessor.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NCV8141D2TG | 功能描述:低壓差穩(wěn)壓器 - LDO 5V 500mA w/WatchDog RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| NCV8141D2TR4 | 功能描述:低壓差穩(wěn)壓器 - LDO 5V 500mA w/WatchDog RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| NCV8141D2TR4G | 功能描述:低壓差穩(wěn)壓器 - LDO ANA WATCHDOG REG RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| NCV8184 | 制造商:ONSEMI 制造商全稱(chēng):ON Semiconductor 功能描述:Micropower 70 mA Low Dropout Tracking Regulator/Line Driver |
| NCV8184/D | 制造商:未知廠(chǎng)家 制造商全稱(chēng):未知廠(chǎng)家 功能描述:Micropower 70mA Low Dropout Tracking Regulator / Line Driver |
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