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參數(shù)資料
| 型號(hào)： | MAX8215 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Microprocessor Voltage Monitors(專(zhuān)用的微處理器電壓監(jiān)視器) |
| 中文描述： | ±5V、±12V (±15V)專(zhuān)用微處理器電壓監(jiān)視器 |
| 文件頁(yè)數(shù)： | 8/12頁(yè) |
| 文件大?。?/td> | 184K |
| 代理商： | MAX8215 |
M
±5V, ±12V (±15V ) Dedic ated
Mic roproc essor Voltage Monitors
8
_______________________________________________________________________________________
Monitoring the S upply V oltage
The supply voltage to these devices can also be moni-
tored by the 5V dedicated comparator and the auxiliary
comparator. Figure 4 shows a circuit that monitors the
voltage connected at V
DD
for both overvoltage and
undervoltage conditions. The +5V comparator checks
for undervoltage conditions while the auxiliary compara-
tor monitors overvoltage conditions. In general, no extra
supply bypassing circuitry (other than the normally rec-
ommended 0.1μF capacitor) is required when perform-
ing this function. However, using resistor values higher
than 100k
at the auxiliary comparator’s input requires
attention to eliminate potential oscillations. Also, partic-
ularly low pull-up resistor values on DOUT contribute to
the likelihood of the auxiliary comparator’s oscillation.
See the section Eliminating Output Oscillation
Mic roproc essor Reset
____________Circ uit with T ime Delay
It is often necessary to reset a microprocessor (μP) when
its supply voltage drops below a certain level. Figure 5’s
circuit generates a low output when the monitored volt-
age drops below the 5V monitor’s threshold. Additionally,
this output remains low for 200ms after the supply voltage
goes above the threshold. μP reset circuits typically
include this feature because it gives the μP time to be
fully reset after power has been restored, and allows any
capacitors in associated circuitry time to charge. Figure
6 shows this circuit’s waveforms and formulas.
Figure 7 shows Figure 5’s μP reset circuit, but with the
monitored supply also powering the MAX8215. Figure
6’s waveforms and equations also apply to this circuit.
The MAX8215/MAX8216 comparator outputs correctly
display a low level down to a 0.8V typical supply voltage.
Unused Inputs
When the uncommitted comparator within the
MAX8215/MAX8216 is not used, tie the unused input to
either the positive supply or ground. This prevents noise
generation due to the comparator output switching from
one logic state to another (due to noise at the input).
Output Pull-Up Resistors
Pull-up resistors are required at the outputs of each
comparator. Resistor values should not be less than
2.7k
if the outputs are pulled up to V
DD
. In general,
save power by using higher values, e.g.,
≥
100k
. Use
of higher-value resistors also minimizes the possibility
of oscillations due to a spurious feedback (see the sec-
tion Eliminating Output Oscillation.
Input V oltage Limitation
If the voltages at the various inputs are kept within the
absolute maximum ratings, the device is not damaged.
However, high input voltages within this range can
cause the reference voltage to move. To prevent the
reference voltage from changing, limit the +5V input to
+17V; the -5V and -15V inputs to +1V; and the +15V
input to +60V. Negative input voltages within the
MAX8215
MAX8216
14
V
DD
8
PGND
0.1
μ
F
OUT1
DOUT
7
13
9
RESET
3
2
+V
S
GND
+5V
DIN
+5V
680k
680k
1
μ
F
Figure 5. Microprocessor Reset Circuit with 200ms Time Delay
V
TRIP2
V
TRIP1
GND
V
DD
INPUT VOLTAGE
(V
S
)
OUTPUT
VOLTAGE
(OUT1)
GND
V
DD
DLY =
-RC In
1 - V
REF
t
CC
)
GND
t
DLY
OUTPUT
VOLTAGE
(DOUT)
V
TRIP1
IS FOR V
S
DECREASING;
V
TRIP2
IS FOR V
S
INCREASING.
NOTE:
V
IS THE VOLTAGE AT THE INVERTING PIN OF THE TWOCOMPARATORS.
IN THIS CASE, IT IS EQUAL TOTHE INTERNAL REFERENCE VOLTAGE.
Figure 6. Microprocessor Reset with Time Delay Waveforms
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX824L | 5-Pin Microprocessor Supervisory Circuits(復(fù)位門(mén)限4.63V,5管腳μP監(jiān)控電路，具看門(mén)狗輸入和高有效復(fù)位) |
| MAX824M | 5-Pin Microprocessor Supervisory Circuits(復(fù)位門(mén)限4.38V,5管腳μP監(jiān)控電路，具看門(mén)狗輸入和高有效復(fù)位) |
| MAX824R | 5-Pin Microprocessor Supervisory Circuits(復(fù)位門(mén)限2.63V,5管腳μP監(jiān)控電路，具看門(mén)狗輸入和高有效復(fù)位) |
| MAX824S | 5-Pin Microprocessor Supervisory Circuits(復(fù)位門(mén)限2.93V,5管腳μP監(jiān)控電路，具看門(mén)狗輸入和高有效復(fù)位) |
| MAX824T | 5-Pin Microprocessor Supervisory Circuits(復(fù)位門(mén)限3.08V,5管腳μP監(jiān)控電路，具看門(mén)狗輸入和高有效復(fù)位) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX8215_05 | 制造商:MAXIM 制造商全稱(chēng):Maxim Integrated Products 功能描述:±5V, ±12V (±15V) Dedicated Microprocessor Voltage Monitors |
| MAX8215C/D | 制造商:MAXIM 制造商全稱(chēng):Maxim Integrated Products 功能描述:【5V, 【12V (【15V) Dedicated Microprocessor Voltage Monitors |
| MAX8215CPD | 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(lèi)型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)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 |
| MAX8215CPD+ | 功能描述:監(jiān)控電路 5/12/15V +/-Dedictd MPU Voltage Monitor 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(lèi)型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)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 |
| MAX8215CSD | 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(lèi)型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)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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