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参数资料
型号： TC1270RERC
厂商： Microchip Technology Inc.
英文描述： 4-Pin レP Reset Monitors
中文描述： 4引脚レP复位监控器
文件页数： 5/12页
文件大小： 467K
代理商： TC1270RERC
2002 Microchip Technology Inc.
DS21381B-page 5
TC1270/TC1271
3.0
APPLICATIONS INFORMATION
3.1
V
CC
Transient Rejection
The TC1270/TC1271 provides accurate V
CC
monitor-
ing and reset timing during power-up, power-down, and
brownout/sag conditions, and rejects negative-going
transients (glitches) on the power supply line. Figure
3-1
shows the
maximum transient
maximum negative excursion (overdrive) for glitch
rejection. 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 brownout or power-down. Transient immunity can be
improved by adding a capacitor in close proximity to the
V
CC
pin of the TC1270/TC1271.
duration
vs.
FIGURE 3-1:
MAXIMUM TRANSIENT
DURATION VS.
OVERDRIVE FOR GLITCH
REJECTION AT 25°C
3.2
RESET Signal Integrity During
Power-Down
The TC1270 RESET output is valid to V
CC
= 1.0V.
Below this voltage the output becomes an "open
circuit" and does not sink current. This means CMOS
logic
inputs
to
the
μ
P
undetermined
voltage.
Most
completely
shut
down
well
However,
in
situations
where
maintained valid to V
CC
= 0V, a pull-down resistor must
will
be
digital
above
RESET
floating
systems
this
at
an
are
voltage.
must
be
be connected from RESET to ground to discharge stray
capacitances and hold the output low (Figure 3-2). This
resistor value, though not critical, should be chosen
such that it does not appreciably load RESET under
normal operation (100k
will be suitable for most
applications). Similarly, a pull-up resistor to V
CC
is
required for the TC1271 to ensure a valid high RESET
for V
CC
below 1.1V.
FIGURE 3-2:
ENSURING RESET VALID
TO V
CC
= 0V
3.3
Processors With Bidirectional
I/O Pins
Some
μ
P's (such as Motorola 68HC11) have bi-
directional reset pins. Depending on the current drive
capability of the processor pin, an indeterminate logic
level may result if there is a logic conflict. This can be
avoided by adding a 4.7 k
resistor in series with the
output of the TC1270/TC1271 (Figure 3-3). If there are
other components in the system which require a reset
signal, they should be buffered so as not to load the
reset line. If the other components are required to
follow the reset I/O of the
μ
P, the buffer should be
connected as shown with the solid line.
FIGURE 3-3:
INTERFACING TO
BIDIRECTIONAL
RESET I/O
RESET COMPARATOR OVERDRIVE,
V
TH
- V
CC
(mV)
400
240
160
320
80
0
1
10
100
1000
M
μ
s
T
A
°
C
V
TH
Duration
Overdrive
V
CC
TC127LMJ
TC127xR/S/T
TC1270
V
CC
V
CC
R1
100k
RESET
GND
TC1270
V
CC
RESET
GND
RESET
GND
Buffered RESET
To Other System
Components
Buffer
μ
P
4.7k
V
CC
V
CC
相关PDF资料
PDF描述
TC1271RERC 4-Pin レP Reset Monitors
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相关代理商/技术参数
参数描述
TC1270RERCTR 功能描述:监控电路 4-Pin uP 2.63V Reset RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel
TC1270SERC 制造商:Microchip Technology Inc 功能描述:
TC1270SERCTR 功能描述:监控电路 4-Pin uP 2.93V Reset RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel
TC1270TERC 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:4-Pin レP Reset Monitors
TC1270TERCTR 功能描述:监控电路 4-Pin uP 38V Reset RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel
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