DSDS1705/DS1706
DS1705/DS1706
3.3 and 5.0 Volt MicroMonitor
FEATURES
PIN ASSIGNMENT
• Halts and restarts an out–of–control microprocessor
• Holds
PBRST
• Automatically
WDS
7
RST
3
6
ST
IN
restarts microprocessor after power
8
2
GND
sients
1
VCC
microprocessor in check during power tran-
4
5
NMI
failure
8–PIN DIP
(300 MIL)
• Monitors pushbutton for external override
WDS
PBRST
7
RST (*RST)
3
6
ST
IN
• Eliminates the need for discrete components
8
2
GND
5% or 10% resets for 5.0 volt systems
1
VCC
• Accurate 5%, 10% or 20% resets for 3.3 systems and
4
5
NMI
• 3.3 volt 20% tolerance for use with 3.0 volt systems
8–PIN SOIC
(150 MIL)
• Pin compatible with the MAXIM MAX705/MAX706 in
PBRST
VCC
GND
IN
8–pin DIP and 8–pin SOIC
• 8–pin DIP, 8–pin SOIC and 8–pin µ–SOP packages
1
2
3
4
8
7
6
5
WDS
RST (*RST)
ST
NMI
8–PIN µ–SOP
(118 MIL)
• Industrial temperature range –40°C to +85°C
See Mech. Drawings
Section
DS1705 and DS1706_/R/S/T (*DS1706L and DS1706P)
PIN DESCRIPTION
PBRST
VCC
GND
IN
NMI
ST
RST
*RST
WDS
–
–
–
–
–
–
–
–
Pushbutton Reset Input
Power Supply
Ground
Input
Non–maskable Interrupt
Strobe Input
Active Low Reset Output
Active High Reset Output
(DS1706P and DS1706L only)
– Watchdog Status Output
DESCRIPTION
The DS1705/DS1706 3.3 or 5.0 Volt MicroMonitor monitors three vital conditions for a microprocessor: power
supply, software execution, and external override. A
precision temperature compensated reference and
comparator circuit monitors the status of VCC at the
device and at an upstream point for maximum protection. When the sense input detects an out–of–tolerance
condition a non–maskable interrupt is generated. As
the voltage at the device degrades an internal power fail
signal is generated which forces the reset to an active
state. When VCC returns to an in–tolerance condition,
the reset signal is kept in the active state for a minimum
of 130 ms to allow the power supply and processor to
stabilize.
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