Philips Semiconductors
System reset with built-in Watchdog timer
Product data
NE56604-42
GENERAL DESCRIPTION
The NE56604-42 is designed to generate a reset signal at a
threshold voltage of 4.2 V for a variety of microprocessor and logic
systems. Accurate reset signals are generated during momentary
power interruptions, or whenever power supply voltages sag to
intolerable levels. The NE56604-42 has a built-in Watchdog Timer to
monitor the microprocessor and ensure it is operating properly. Any
abnormal system operations due to microprocessor malfunctions
are terminated by a system reset generated by the Watchdog. The
NE56604-42 has a Watchdog monitoring time of 100 ms (typical).
The NE56604-42 is offered in the SO8 surface mount package
(SOP005).
FEATURES
• Both positive and negative logic reset output signals are available
• Accurate threshold detection
• Internal power-on reset delay
• Internal Watchdog timer programmable with external resistor
• Watchdog monitoring time of 100 ms (typical)
• Reset assertion with VCC down to 0.8 VDC (typical)
• Few external components required.
APPLICATIONS
• Microcomputer systems
• Logic systems.
SIMPLIFIED SYSTEM DIAGRAM
VCC
5
RCT
VS 7
NE56604-42
R
R
VREF
C
6 RCT
RESET
GENERATOR
PROGRAMMABLE
WATCHDOG TIMER
8 RESET
2 RESET
3 CLK
4 GND
1 CT
LOGIC
SYSTEM
RESET
RESET
CLK
GND
Figure 1. Simplified system diagram.
SL01281
2003 Oct 15
2