MAX705CUA MAXIM [Maxim Integrated Products], MAX705CUA Datasheet - Page 8

• Manufacturer Part Number: MAX705CUA
• Description: Low-Cost, ?P Supervisory Circuits
• Manufacturer: MAXIM [Maxim Integrated Products]

Low-Cost, µP Supervisory Circuits
Figure 5. RESET Valid to Ground Circuit
Figure 7. Monitoring a Negative Voltage
8
_______________________________________________________________________________________
+5V
V-
PFO
MR
+5V
+5V
R1
R2
0V
0V
5 1.25
−
R1
MAX70_
=
1.25
RESET
V-
PFI
−
R2
V TRIP
MAX70_
GND
V
CC
V
RESET
TRIP
, V TRIP
PFO
MR
R1
<
100kΩ
0
0V
2N3904
TO µP
100kΩ
µPs with bidirectional reset pins, such as the Motorola
68HC11 series, can contend with the MAX705-MAX708
RESET output. If, for example, the RESET output is driven
high and the µP wants to pull it low, indeterminate logic
levels may result. To correct this, connect a 4.7kΩ
resistor between the RESET output and the µP reset I/O,
as in Figure 8. Buffer the RESET output to other system
components.
Figure 6. Monitoring Both +5V and +12V
Figure 8. Interfacing to µPs with Bidirectional Reset I/O
130kΩ
1MΩ
1%
1%
MAX70_
GND
V
+12V
+12V Reset
Threshold at +25°C
CC
PARAMETER
RESET
+5V
BUFFERED RESET TO OTHER SYSTEM COMPONENTS
4.7kΩ
PFI
V
Bidirectional Reset Pins
CC
MIN
10.67
Interfacing to µPs with
MAX70_
GND
TYP
10.87
RESET
PFO
MR
RESET
MAX
11.50
GND
V
µP
CC
UNIT
V
TO µP