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參數(shù)資料
| 型號： | MAX692A |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Microprocessor Supervisory Circuits(帶看門狗和電池開關(guān)復(fù)位器,復(fù)位閾值4.40V) |
| 中文描述： | 微處理器監(jiān)控電路 |
| 文件頁數(shù)： | 7/12頁 |
| 文件大?。?/td> | 122K |
| 代理商： | MAX692A |
M
Mic roproc essor S upervisory Circ uits
_______________________________________________________________________________________
7
SW1/SW2
SW3/SW4
CONDITION
V
CC
> Reset Threshold
Open
Closed
Closed
Open
Open
Closed
V
CC
< Reset Threshold and
V
CC
> V
BATT
V
CC
< Reset Threshold and
V
CC
< V
BATT
RESET THRESHOLD = 4.65V IN MAX690A/MAX802L/MAX805L.
RESET THRESHOLD = 4.4V IN MAX692A/MAX802M
V
OUT
D3
SUBSTRATE
D1
D2
SW2
SW1
SW4
SW3
V
BATT
V
CC
MAX690A
MAX692A
MAX802L
MAX802M
MAX805L
Figure 3. Backup-Battery Switchover Block Diagram
V
BATT
V
CC
V
OUT
RESET
(RESET)
GND
TOSTATIC RAM
TO
μ
P
0.1F
MAX690A
MAX802L
MAX805L
+5V
+
( ) ARE FOR MAX805L ONLY.
Figure 4. Using a SuperCap as a Backup Power Source with a
MAX690A/MAX802L/MAX805L and a +5V ±5% Supply
need not be dedicated to this function though, as it is
completely separate from the rest of the circuitry. The
external voltage divider drives PFI to sense the unregu-
lated DC input to the +5V regulator (see Typical
Operating Circuit. The voltage-divider ratio can be
chosen such that the voltage at PFI falls below 1.25V
just before the +5V regulator drops out.
PFO
then trig-
gers an interrupt which signals the μP to prepare for
power-down.
To conserve backup-battery power, the power-fail
detector comparator is turned off and
PFO
is forced
low when V
BATT
connects to V
OUT
.
Bac kup-Battery S witc hover
In the event of a brownout or power failure, it may be
necessary to preserve the contents of RAM. With a
backup battery installed at V
, the devices automati-
cally switch RAM to backup power when V
CC
fails.
As long as V
exceeds the reset threshold, V
connects
to V
through a 5
PMOS power switch. Once V
falls
below the reset threshold, V
or V
(whichever is high-
er) switches to V
. Unlike the MAX690/MAX692, the
MAX690A/MAX692A/MAX802L/MAX802M/MAX805L don’t
always connect V
to V
OUT
when V
is greater than
V
. V
BATT
connects to V
(through an 80
switch) only
when V
CC
is below the reset threshold
and
V
BATT
is greater
than V
CC
.
When V
exceeds the reset threshold, it is connected to
the MAX690A/MAX692A/MAX802L/MAX802M/MAX805L
substrate, regardless of the voltage applied to V
BATT
(Figure 3). During this time, the diode (D1) between V
BATT
and the substrate will conduct current from V
BATT
to V
CC
if
Table 1. Input and Output Status in Battery-Backup Mode
SIGNAL
STATUS
V
CC
Disconnected from V
OUT
V
OUT
V
BATT
PFI
Power-fail comparator is disabled.
PFO
Logic low
RESET
Logic low
RESET
Logic high (MAX805L only)
WDI
Watchdog timer is disabled
Connected to V
BATT
through an internal 80
PMOS switch
Connected to V
OUT
. Current drawn from the
battery is less than 1μA, as long as
V
CC
< V
BATT
- 1V.
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PDF描述 |
|---|---|
| MAX8069 | Low-Voltage Reference |
| MAX8069ESA | Low-Voltage Reference |
| MAX8069CCZQ | Low-Voltage Reference |
| MAX807MCUE | Full-Featured uP Supervisory Circuit with +/-1.5% Reset Accuracy |
| MAX810 | 3-Pin Microprocessor Reset Circuits(3管腳微處理器復(fù)位監(jiān)視器) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX692AC/D | 功能描述:監(jiān)控電路 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 |
| MAX692AC/D DIE | 制造商:Maxim Integrated Products 功能描述: |
| MAX692ACPA | 功能描述:監(jiān)控電路 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 |
| MAX692ACPA+ | 功能描述:監(jiān)控電路 MPU Supervisor 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 |
| MAX692ACSA | 功能描述:監(jiān)控電路 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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