參數(shù)資料
型號(hào)： MAX794
廠商： Maxim Integrated Products, Inc.
英文描述： 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits(具有可調(diào)閾值監(jiān)控器、芯片使能和支持備用電池的復(fù)位器)
中文描述： 3.0V/3.3V可調(diào)、微處理器監(jiān)控電路
文件頁(yè)數(shù)： 10/20頁(yè)
文件大小： 211K
代理商： MAX794
M
Reset T hreshold
The MAX793T/MAX795T are intended for 3.3V systems
with a ±5% power-supply tolerance and a 10% systems
tolerance. Except when MR is asserted, reset will not
assert as long as the power supply remains above
3.15V (3.3V - 5%). Reset is guaranteed to assert
before the power supply falls below 3.0V (3.3V - 10%).
The MAX793S/MAX795S are designed for 3.3V ±10%
power supplies. Except when MR is asserted, they are
guaranteed not to assert reset as long as the supply
remains above 3.0V (3.0V is just above 3.3V - 10%).
Reset is guaranteed to assert before the power supply
falls below 2.85V (3.3V - 14%).
The MAX793R/MAX795R are optimized to monitor 3.0V
±10% power supplies. Reset will not occur until V
CC
falls below 2.7V (3.0V - 10%), but is guaranteed to
occur before the supply falls below 2.55V (3.0V - 15%).
Program the MAX794’s reset threshold with an external
voltage divider to RESET IN. The reset-threshold toler-
ance will be a combination of the RESET IN tolerance
and the tolerance of the resistors used to make the
external voltage divider. Calculate the reset threshold
as follows:
V
RST
= V
RST IN
(R1 / R2 + 1)
Using the standard application circuit (Figure 3), the
reset threshold may be programmed anywhere in the
range of V
SW
(the battery switch threshold) to 5.5V.
Reset is asserted when V
CC
falls below V
SW
.
Battery Freshness S eal
The MAX793/MAX794’s battery freshness seal discon-
nects the backup battery from internal circuitry until it is
needed. This allows an OEM to ensure that the backup
battery connected to BATT will be fresh when the final
product is put to use. To enable the freshness seal,
connect a battery to BATT, ground PFO, bring V
CC
above the reset threshold and hold it there until reset is
deasserted following the reset timeout period, then
bring V
CC
back down again (Figure 4). Once the bat-
tery freshness seal is enabled (disconnecting the back-
up battery from the internal circuitry and anything
connected to OUT), it remains enabled until V
CC
is
brought above V
RST
. Note that connecting PFO to MR
will not interfere with battery freshness seal operation.
BAT T OK Output (MAX 793)
BATT OK indicates the status of the backup battery.
When reset is not asserted, the MAX793 checks the
battery voltage continuously. If V
BATT
is below V
BOK
(2.0V min), BATT OK goes low; otherwise, it remains
pulled up to V
CC
. BATT OK also goes low when V
CC
goes below V
SW
.
Watc hdog Input (MAX 793/MAX 794)
In the MAX793/MAX794, the watchdog circuit monitors
the μP’s activity. If the μP does not toggle the watch-
dog input (WDI) within 1.6sec, WDO goes low. The
internal 1.6sec timer is cleared and WDO returns high
3.0V /3.3V Adjustable Mic roproc essor
S upervisory Circ uits
10
______________________________________________________________________________________
MAX794
RESET
LOWLINE
WDI
CE IN
CE OUT
3.3V
+5V
BATT
RESET IN
A0-A15
MR
+5V SUPPLY
FAILURE
BATT ON
PFI
4.7k
WDO
OUT
CMOS
RAM
ADDRESS
DECODER
0.1
μ
F
PMOS
0.1
μ
F
V
CC
PFO
V
RST
= V
RST IN
(
R2
)
GND
I/O
NMI
RESET
V
CC
V
CC
0.1
μ
F
3.6V
R1
D
S
R2
(OPTIONAL)
Si9433DY
SILICONIX
Figure 3. MAX794 Standard Application Circuit
V
CC
V
RST
V
RST
RESET
PFO
(EXTERNALLY HELD AT 0V)
RESET PULLED UP TOV
CC
PFOSTATE LATCHED,
FRESHNESS SEAL ENABLED.
t
RP
Figure 4. Battery Freshness Seal Enable Timing
相關(guān)PDF資料
PDF描述
MAX796 Step-Down Controllers with Synchronous Rectifier for CPU Power(3.3V/5V/可調(diào),帶有同步整流器的PWM步降控制器，用于筆記本電腦)
MAX797 Step-Down Controllers with Synchronous Rectifier for CPU Power(3.3V/5V/可調(diào),帶有同步整流器的PWM步降控制器，用于筆記本電腦)
MAX797CPE Octal Bus Transceivers With 3-State Outputs 20-CDIP -55 to 125
MAX796-MAX799 Octal Buffers And Line Drivers With 3-State Outputs 20-CDIP -55 to 125
MAX796CPE Octal Buffers And Line Drivers With 3-State Outputs 20-CDIP -55 to 125
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX794CPE 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)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
MAX794CPE+ 功能描述:監(jiān)控電路 3/3.3/AdjV MPU Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)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
MAX794CSE 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)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
MAX794CSE+ 功能描述:監(jiān)控電路 3/3.3/AdjV MPU Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)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
MAX794CSE+T 功能描述:監(jiān)控電路 3/3.3/AdjV MPU Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)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
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*