TC1278_07 Datasheet, PDF (1/12 Pages) Microchip Technology – 3-Pin Reset Monitors for 5V Systems

Obsolete Device
TC1278/TC1279
3-Pin Reset Monitors for 5V Systems
Features
• Precision V_CC Monitor for 5.0V System Supplies
• 250 ms Minimum RESET Output Duration
• Output Valid to V_CC = 1.2V
• V_CC Transient Immunity
• Small 3-Pin SOT-23 Package
• No External Components
• Internal Pull-up Resistor
• Available in 3 different voltage detection levels:
- 4.625V (typ.), -5 suffix
- 4.375V (typ.), -10 suffix
- 4.125V (typ.), -15 suffix
Applications
• Computers
• Embedded Systems
• Battery Powered Equipment
• Critical µP Power Supply Monitoring
Typical Operating Circuit
V_CC
Internal
Pull-up
6 kΩ
Resistor
RESET
–
+
V_REF
TC1279
General Description
The TC1278/TC1279 are cost-effective system super-
visor circuits designed to monitor V_CC in digital systems
and provide a reset signal to the host processor when
necessary. No external components are required. The
open-drain output uses an internal pull-up resistor of
approximately 6 kΩ.
The reset output is driven active within 5 µs of V_CC
falling through the reset voltage threshold. RESET is
maintained active for a minimum of 250 ms after V_CC
rises above the reset threshold. The TC1278 has an
active-high RESET output, while the TC1279 has an
active-low RESET output, with both devices having an
open-drain output stage. The output is valid down to
V_CC = 1.2V. Both devices are available in a 3-Pin
SOT- 23 package.
Package Type
3-Pin SOT-23
(TC1278) RESET
(TC1279) RESET
1
TC1278
TC1279
3 GND
V_{CC 2}
GND
TC1278 has an active-high RESET output.
© 2007 Microchip Technology Inc.
DS21384D-page 1