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參數(shù)資料
| 型號： | MAX16057ATT21+T |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 電源管理 |
| 英文描述： | 125nA Supervisory Circuits with Capacitor-Adjustable Reset and Watchdog Timeouts; Package: Land Pattern: Not Available; Temperature: -40°C to +125°C |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, DSO6 |
| 封裝： | 3 X 3 MM, ROHS COMPLIANT, TDFN-6 |
| 文件頁數(shù)： | 14/16頁 |
| 文件大?。?/td> | 772K |
| 代理商： | MAX16057ATT21+T |
MAX16056–MAX16059
125nA Supervisory Circuits with Capacitor-
Adjustable Reset and Watchdog Timeouts
_______________________________________________________________________________________
7
Detailed Description
The MAX16056–MAX16059 are ultra-low-current 125nA
(typ) P supervisory circuits that monitor a single sys-
tem supply voltage. These devices assert an active-low
reset signal whenever the VCC supply voltage drops
below the factory-trimmed reset threshold, manual
reset is pulled low, or the watchdog timer runs out
(MAX16056/MAX16058). The reset output remains
asserted for an adjustable reset timeout period after
VCC rises above the reset threshold. The reset and
watchdog delay periods are adjustable using external
capacitors.
RESET Output
The MAX16056–MAX16059 P supervisory circuits assert
a reset to prevent code-execution errors during power-
up, power-down, and brownout conditions. The reset
output is guaranteed to be valid for VCC down to 1.1V.
When VCC falls below the reset threshold, the RESET
output asserts low. Once VCC exceeds the reset thresh-
old plus the hysteresis, an internal timer keeps the reset
output asserted for the capacitor-adjusted reset timeout
period (tRP), then after this interval the reset output
deasserts (see Figure 1). The reset function features
immunity to power-supply voltage transients.
Manual-Reset Input (
MR)
Many P-based products require manual-reset capabil-
ity, allowing the operator, a test technician, or external
logic circuitry to initiate a reset. The MAX16056–
MAX16059 feature an MR input. A logic-low on MR
asserts a reset. RESET remains asserted while MR is
low and for the timeout period, tRP, after MR returns
high. Connect MR to VCC if unused. MR can be driven
with CMOS logic levels or with open-drain/collector out-
puts (with a pullup resistor). Connect a normally open
momentary switch from MR to GND and a resistor from
MR to VCC to implement a manual-reset function; exter-
nal debounce circuitry is not required. If MR is driven
by long cables or the device is used in a noisy environ-
ment, connect a 0.1F capacitor from MR to GND to
provide additional noise immunity.
Watchdog Timer
The MAX16056/MAX16058’s watchdog timer circuitry
monitors the P’s activity. If the P does not toggle
(high-to-low) the watchdog input (WDI) within the
capacitor-adjustable watchdog timeout period (tWD),
RESET asserts for the reset timeout period (tRP). The
internal watchdog timer is cleared by: 1) any event that
asserts RESET, by 2) a falling transition at WDI (that
can detect pulses as short as 150ns) or by 3) a transi-
tion (high-to-low or low-to-high) at WDS. While reset is
asserted, the watchdog timer remains cleared and
does not count. As soon as reset deasserts, the watch-
dog timer resumes counting.
There are two modes of watchdog operation, normal
mode and extended mode. In normal mode (Figure 2),
the watchdog timeout period is determined by the
value of the capacitor connected between SWT and
ground. In extended mode (Figure 3), the watchdog
timeout period is multiplied by 128. For example, in
extended mode, a 0.33F capacitor gives a watchdog
timeout period of 212s (see Table 2). To disable the
watchdog timer function, connect SWT to ground.
When VCC ramps above VTH + VHYST, the value of the
external SWT capacitor is sampled after RESET goes
high. When sampling is finished, the capacitor value is
stored in the device and is used to set watchdog time-
out. If RESET goes low before sampling is finished, the
device interrupts sampling, and sampling is restarted
when RESET goes high again.
If the external SWT capacitor is less than 470pF, the
sampling result sets the watchdog timeout to zero. This
causes the watchdog to assert RESET continuously
after sampling is finished. If a PCB manufacturing
defect caused the connection to CSWT to be broken,
the capacitance is very low and RESET is continuously
asserted. If the external SWT capacitor is greater than
5600pF, the sampling result sets the watchdog timeout
to be infinite, disabling the watchdog function.
相關(guān)PDF資料 |
PDF描述 |
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| MAX16057ATT22+T | 125nA Supervisory Circuits with Capacitor-Adjustable Reset and Watchdog Timeouts; Package: Land Pattern: Not Available; Temperature: -40°C to +125°C |
| MAX16057ATT24+T | 125nA Supervisory Circuits with Capacitor-Adjustable Reset and Watchdog Timeouts; Package: Land Pattern: Not Available; Temperature: -40°C to +125°C |
| MAX16057ATT25+T | 125nA Supervisory Circuits with Capacitor-Adjustable Reset and Watchdog Timeouts; Package: Land Pattern: Not Available; Temperature: -40°C to +125°C |
| MAX16057ATT27+T | 125nA Supervisory Circuits with Capacitor-Adjustable Reset and Watchdog Timeouts; Package: Land Pattern: Not Available; Temperature: -40°C to +125°C |
| MAX16057ATT28+T | 125nA Supervisory Circuits with Capacitor-Adjustable Reset and Watchdog Timeouts; Package: Land Pattern: Not Available; Temperature: -40°C to +125°C |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX16057ATT22+ | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX16057ATT22+T | 功能描述:監(jiān)控電路 NanoPwr w/Cap-Adj Reset and Watchdog 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 |
| MAX16057ATT23+T | 功能描述:監(jiān)控電路 NanoPwr w/Cap-Adj Reset and Watchdog 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 |
| MAX16057ATT24+ | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX16057ATT24+T | 功能描述:監(jiān)控電路 NanoPwr w/Cap-Adj Reset and Watchdog 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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