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參數資料
| 型號： | LP3971SQX-A514 |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 電源管理 |
| 英文描述： | POWER MANAGEMENT UNIT FOR ADVANCED APPLICATION PROCESSORS |
| 中文描述： | 3-CHANNEL POWER SUPPLY SUPPORT CKT, PQCC40 |
| 封裝： | 5 X 5 MM, LLP-40 |
| 文件頁數： | 38/42頁 |
| 文件大?。?/td> | 1350K |
| 代理商： | LP3971SQX-A514 |
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Application Note
(Continued)
Code Start Power on Timing
20180722
POWER-ON TIMING
Symbol
t1
t3
t4
t5
Description
Min
50
Typ
Max
Units
mS
mS
mS
mS
Delay from VCC_RTC assertion to nRSTO de-assertion
Delay from nRST de-assertion to SYS_EN assertion
Delay from SYS_EN assertion to PWR_EN assertion
Delay from PWR_EN assertion to nRSTO de-assertion
10
125
125
LP3971 & PXA27x RESET SEQUENCE
Hardware Reset Sequence
Hardware reset initiates when the nRSTI signal is asserted
(low). Upon assertion of nRST the processor enters hard-
ware reset state. The LP3971 holds the nRST low long
enough (50ms typ.) to allow the processor time to initiate the
reset state.
Reset Sequence
1.
nRSTI is asserted
2.
If V
is above the set point the PMIC de-asserts
nBATT_FLT to indicate system power (V
IN
) is available.
3.
nRSTO is asserted and will de-asserts after a minimum
of 50 mS.
4.
The Applications processor asserts SYS_EN, the
LP3971 enables the system high-voltage power sup-
plies. The Applications processor starts its countdown
timer set to 125 mS.
The LP3971 enables the high-voltage power supplies.
Countdown timer expires; the Applications processor
asserts PWR_EN to enable the low-voltage power sup-
plies. The processor starts the countdown timer set to
125 mS period.
The Applications processor asserts PWR_EN, the
LP3971 enables the low-voltage regulators.
Countdown timer expires; If enabled power domains are
OK (I
2
C read) the power up sequence continues by
enabling the processors 13 MHz oscillator and PLL’s.
The Applications processor begins the execution of
code.
5.
6.
7.
8.
9.
L
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| LP3971SQX-B410 | POWER MANAGEMENT UNIT FOR ADVANCED APPLICATION PROCESSORS |
| LP3994 | 50mA CMOS Voltage Regulator with Enable Control |
| LP3994LD-1.5 | 50mA CMOS Voltage Regulator with Enable Control |
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相關代理商/技術參數 |
參數描述 |
|---|---|
| LP3971SQX-B410 | 功能描述:PMIC 解決方案 RoHS:否 制造商:Texas Instruments 安裝風格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
| LP3971SQX-B410/NOPB | 功能描述:PMIC 解決方案 RoHS:否 制造商:Texas Instruments 安裝風格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
| LP3971SQX-B510/NOPB | 功能描述:PMIC 解決方案 RoHS:否 制造商:Texas Instruments 安裝風格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
| LP3971SQX-D510 | 功能描述:PMIC 解決方案 RoHS:否 制造商:Texas Instruments 安裝風格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
| LP3971SQX-D510/NOPB | 功能描述:PMIC 解決方案 RoHS:否 制造商:Texas Instruments 安裝風格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
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