TC1270/TC1271
4-Pin µP Reset Monitors
Features
Package Type
• Precision V Monitor for 1.8V, 2.7V, 3.0V, 3.3V
and 5.0V Nominal Supplies
4-Pin SOT-143
CC
• Manual Reset Input
V
4
3
CC
• 140msec Minimum RESET, RESET Output
Duration
1
2
GND
TC1270
TC1271
• RESET Output Valid to V = 1.0V (TC1270)
CC
• Low 7µA Supply Current
• V Transient Immunity
CC
MR
TC1270 RESET
TC1271 (RESET)
• Small 4-Pin SOT-143 Package
• No External Components
• Replacement for MAX811/812 and Offers a Lower
Threshold Voltage Option
General Description
The TC1270 and TC1271 are cost-effective system
supervisor circuits designed to monitor V in digital
Applications
CC
• Computers
systems and provide a reset signal to the host
processor when necessary. A manual reset input is
provided to override the reset monitor, and is suitable
• Embedded Systems
• Battery Powered Equipment
• Critical µP Power Supply Monitoring
for use as
a
push-button reset. No external
components are required.
The reset output is driven active within 20µsec (4µsec
Device Selection Table
for F version) of V falling through the reset voltage
CC
Part Number
Package
Temp. Range
threshold. RESET is maintained active for a minimum
of 140msec after V rises above the reset threshold.
The TC1271 has an active-high RESET output while
the TC1270 has an active-low RESET output. The
CC
TC1270xERC
TC1271xERC
4-Pin SOT-143 -40°C to +85°C
4-Pin SOT-143 -40°C to +85°C
output of the TC1270 is valid down to V = 1V. Both
devices are available in a 4-Pin SOT-143 package.
CC
NOTE: “x” denotes a suffix for VCC threshold (see table
below)
The TC1270/TC1271 devices are optimized to reject
Suffix*
Reset V Threshold (V)
CC
fast transient glitches on the V
line. Low supply
CC
current of 7µA (V
= 3.3V) makes these devices
suitable for battery powered applications.
L
M
T
4.63
4.38
3.08
2.93
2.63
1.75
CC
Typical Operating Circuit
S
R
F
V
CC
V
V
CC
CC
Processor
*Custom thresholds available, contact factory.
RESET
Input
MR
RESET
Push-
Button
(Active Low)
TC1270
GND
GND
2002 Microchip Technology Inc.
DS21381B-page 1