參數(shù)資料
型號: TC1270AMCVCTTR
廠商: Microchip Technology Inc.
英文描述: Voltage Supervisor with Manual Reset Input
中文描述: 電壓監(jiān)控器,帶有手動復位輸入
文件頁數(shù): 21/40頁
文件大小: 384K
代理商: TC1270AMCVCTTR
2007 Microchip Technology Inc.
DS22035B-page 21
TC1270A/70AN/71A
4.3
Negative Going V
DD
Transients
The minimum pulse width (time) required to cause a
Reset may be an important criteria in the implementa-
tion of a Power-on Reset (POR) circuit. This time is
referred to as transient duration. The TC127XA devices
are designed to reject a level of negative-going
transients (glitches) on the power supply line.
Transient duration is the amount of time needed for
these supervisory devices to respond to a drop in V
DD
.
The transient duration time (t
TRAN
) is dependent on the
magnitude of V
TRIP
– V
DD
(overdrive). Any combination
of duration and overdrive that lies under the
duration/overdrive curve will not generate a Reset
signal. Generally speaking, the transient duration time
decreases with an increase in the V
TRIP
– V
DD
voltage.
Figure 4-9
shows an example transient duration vs.
Reset comparator overdrive. It shows that the farther
below the trip point the transient pulse goes, the
duration of the pulse required to cause a Reset gets
shorter. So any combination of duration and overdrive
that lays
under
the curve will
not
generate a Reset
signal. Combinations
above
the curve are detected as
a brown-out or power-down.
Transient immunity can be improved by adding a
bypass capacitor (typically 0.1 μF) as close as possible
to the V
DD
pin of the TC127XA device.
FIGURE 4-9:
Transient Duration Waveform.
Example of Typical
4.4
Manual Reset with Glitch Filter
Circuit
The Manual Reset input pin (MR) allows the Reset pins
(RST/RST) to be manually forced to their active states.
The MR pin has circuitry to filter noise pulses that may
be present on the pin.
Figure 4-10
shows a block
diagram for using the TC127XA with a push button
switch. To minimize the required external components,
the MR input has an internal pull-up resistor.
A mechanical push button or active logic signal can
drive the MR input.
Once MR has been low for a time, t
MD
(the Manual
Reset delay time), the Reset output pins are forced
active. The Reset output pins will remain in their active
states for the Reset delay timer time out period (t
RST
).
Figure 4-11
shows a waveform for the Manual Reset
switch input and the Reset pins output.
FIGURE 4-10:
Push Button Reset.
FIGURE 4-11:
MR Input – Push Button.
4.4.1
NOISE FILTER
The noise filter filters out noise spikes (glitches) on the
Manual Reset pin (MR). Noise spikes less than 100 ns
(typical) are filtered.
Time (μs)
0V
S
5V
V
TRIP(MIN)
- V
DD
(Overdrive)
t
TRAN
(Duration)
V
TRIP(MAX)
V
TRIP(MIN)
Transient Overdrive Voltage (mV)
T
Area below curve will
not generate a reset signal
Area above curve will
generate a reset signal
V
DD
MR
V
SS
RST
MCLR
+5V
TC127XA
PIC
MCU
RST
V
IL
t
MR
RST
t
MD
V
IH
t
RST
MR
The MR input typically ignores input pulses
of 100 ns.
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TC1270AMCVRCTR 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:Voltage Supervisor with Manual Reset Input
TC1270AMVCTTR 功能描述:監(jiān)控電路 5Pin uP Reset Mon 4.38V Reset Thresh 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
TC1270AMVRCTR 功能描述:監(jiān)控電路 4Pin uP Reset Mon 4.38V Reset Thresh 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
TC1270AN 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:Voltage Supervisor with Manual Reset Input
TC1270ANLBVCTTR 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:Voltage Supervisor with Manual Reset Input