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參數資料
| 型號： | MAX691A |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Microprocessor Supervisory Circuits(帶看門狗復位、片選和支持備用電池的復位器) |
| 中文描述： | 微處理器監(jiān)控電路 |
| 文件頁數： | 12/16頁 |
| 文件大?。?/td> | 164K |
| 代理商： | MAX691A |
M
Bac kup-Battery Input
The Backup-Battery Input (VBATT) is similar to the V
input except the PMOS switch and parallel diode are
much smaller. Accordingly, the on-resistances of the
diode and the switch are each approximately 10
.
Continuous current should be limited to 25mA and
peak currents (only during power-up) limited to 250mA.
The reverse leakage of this input is less than 1μA over
temperature and supply voltage (Figure 8).
Output S upply V oltage
The Output Supply Voltage (V
) pin is internally con-
nected to the substrate of the IC and supplies current
to the external system and internal circuitry. All open-
circuit outputs will, for example, assume the V
volt-
age in their high states rather than the V
CC
voltage. At
the maximum source current of 250mA, V
will typi-
cally be 200mV below V
CC
. Decouple this terminal with
a 0.1μF capacitor.
__________Applic ations Information
The MAX691A/MAX693A/MAX800L/MAX800M are not
short-circuit protected. Shorting V
OUT
to ground, other
than power-up transients such as charging a decou-
pling capacitor, destroys the device.
All open-circuit outputs swing between V
OUT
and GND
rather than V
CC
and GND.
If long leads connect to the chip inputs, insure that
these leads are free from ringing and other conditions
that would forward bias the chip’s protection diodes.
There are three distinct modes of operation:
1) Normal operating mode with all circuitry powered
up. Typical supply current from V
is 35μA while
only leakage currents flow from the battery.
2) Battery-backup mode where V
is typically within
0.7V below VBATT. All circuitry is powered up
and the supply current from the battery is typically
less than 60μA.
3) Battery-backup mode where V
is less than
VBATT by at least 0.7V. VBATT supply current is
1μA max.
Using S uperCaps or MaxCaps with the
MAX 691A/MAX 693A/MAX 800L/MAX 800M
VBATT has the same operating voltage range as V
,
and the battery switchover threshold voltages are typi-
cally ±30mV centered at VBATT, allowing use of a
SuperCap and a simple charging circuit as a backup
source (Figure 9).
If V
is above the reset threshold and VBATT is 0.5V
above V
, current flows to V
and V
from VBATT
until the voltage at VBATT is less than 0.5V above V
.
For example, with a SuperCap connected to VBATT and
through a diode to V
, if V
quickly changes from 5.4V
to 4.9V, the capacitor discharges through V
and V
until VBATT reaches 5.1V typ. Leakage current through
the SuperCap charging diode and the internal power
diode eventually discharges the SuperCap to V
. Also, if
V
and VBATT start from 0.1V above the reset threshold
and power is lost at V
CC
, the SuperCap on VBATT dis-
charges through V
until VBATT reaches the reset
threshold; then the battery-backup mode is initiated and
the current through V
CC
goes to zero.
Mic roproc essor S upervisory Circ uits
12
______________________________________________________________________________________
MAX691A
MAX693A
MAX800L
MAX800M
VBATT
V
CC
0.1
μ
F
V
OUT
MAX691A
MAX693A
MAX800L
MAX800M
1
0.47F*
1N4148
5V
2
3
V
CC
GND
VBATT
4
V
OUT
* MaxCap
Figure 8. V
CC
and VBATT to V
OUT
Switch
Figure 9. SuperCap or MaxCap on VBATT
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相關代理商/技術參數 |
參數描述 |
|---|---|
| MAX691AC/D | 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數: 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關:No Backup 上電復位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| MAX691ACPE | 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數: 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關:No Backup 上電復位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| MAX691ACPE+ | 功能描述:監(jiān)控電路 MPU Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數: 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關:No Backup 上電復位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| MAX691ACSE | 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數: 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關:No Backup 上電復位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| MAX691ACSE+ | 功能描述:監(jiān)控電路 MPU Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數: 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關:No Backup 上電復位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
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