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TC1270A Datasheet, PDF (23/40 Pages) Microchip Technology – Voltage Supervisor with Manual Reset Input
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5.0 APPLICATION INFORMATION
This section shows application related information that
may be useful for your particular design requirements.
5.1 Supply Monitor Noise Sensitivity
The TC127XA devices are optimized for fast response
to negative-going changes in VDD. Systems with an
inordinate amount of electrical noise on VDD (such as
systems using relays) may require a 0.01 µF or 0.1 µF
bypass capacitor to reduce detection sensitivity. This
capacitor should be installed as close to the TC127XA
as possible to keep the capacitor lead length short.
VDD
TC127XA
RST
MR
RST
VSS
0.1 µF
FIGURE 5-1:
Typical Application Circuit
with Bypass Capacitor.
5.2 Conventional Voltage Monitoring
Figure 5-2 and Figure 5-3 show the TC127XA in
conventional voltage monitoring applications.
+
VDD
–
TC127XA
BATLOW
RST
VSS
FIGURE 5-2:
Battery Voltage Monitor.
VDD
+
Pwr
Sply
RST
TC127XA
Power Good
–
VSS
FIGURE 5-3:
Power Good Monitor.
TC1270A/70AN/71A
5.3 Using in PIC® Microcontroller,
ICSP™ Applications
Note:
This operation can only be done using the
device with the Open-Drain RST pin
(TC1270AN).
Figure 5-4 shows the typical application circuit for using
the TC1270AN for voltage supervisory function when
the PIC microcontroller will be programmed via the
In-Circuit Serial Programming™ (ICSP™) feature.
Additional information is available in TB087, “Using
Voltage Supervisors with PICmicro® Microcontroller
Systems which Implement In-Circuit Serial Program-
ming™”, DS91087.
Note:
It is recommended that the current into the
RST pin be current limited by a 1 kΩ
resistor.
VDD
TC1270AN
RST
VSS
0.1 µF
1 kΩ
VDD/VPP
RPU
VDD
PIC®
Microcontroller
MCLR
Reset input)
(Active-Low)
VSS
FIGURE 5-4:
Typical Application Circuit
for PIC® Microcontroller with the ICSP™
Feature.
© 2007 Microchip Technology Inc.
DS22035B-page 23
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