MAX795SCSA+ Maxim Integrated Products, MAX795SCSA+ Datasheet - Page 17
![IC SUPERVISOR MPU 8-SOIC](/photos/1/39/13902/8-soic_21-0042b_sml.jpg)
MAX795SCSA+
Manufacturer Part Number
MAX795SCSA+
Description
IC SUPERVISOR MPU 8-SOIC
Manufacturer
Maxim Integrated Products
Type
Battery Backup Circuitr
Datasheet
1.MAX795TCSA.pdf
(20 pages)
Specifications of MAX795SCSA+
Number Of Voltages Monitored
1
Output
Open Drain or Open Collector
Reset
Active Low
Reset Timeout
140 ms Minimum
Voltage - Threshold
2.925V
Operating Temperature
0°C ~ 70°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width)
Monitored Voltage
3 V or 3.3 V
Undervoltage Threshold
Adj V
Overvoltage Threshold
Adj V
Manual Reset
No
Watchdog
No
Battery Backup Switching
Yes
Power-up Reset Delay (typ)
280 ms
Supply Voltage (max)
5.5 V
Supply Voltage (min)
1 V
Supply Current (typ)
49 uA (Typ)
Maximum Power Dissipation
471 mW
Mounting Style
SMD/SMT
Maximum Operating Temperature
+ 70 C
Chip Enable Signals
No
Minimum Operating Temperature
0 C
Output Type
Active Low or Open Drain
Power Fail Detection
No
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Figure 16. Adding Hysteresis to the Power-Fail Comparator: (a) Symmetrical Hysteresis, (b) Hysteresis Only on Rising V
These µP supervisors can monitor either positive or
negative supplies using a resistor voltage divider to
PFI. PFO can be used to generate an interrupt to the µP
or to cause reset to assert (Figure 12).
Since the RESET output is open drain, the MAX793/
MAX794/MAX795 interface easily with µPs that have
bidirectional reset pins, such as the Motorola 68HC11.
Connecting the RESET output of the µP supervisor
directly to the RESET input of the microcontroller with a
single pullup resistor allows either device to assert
reset (Figure 17).
These supervisors are relatively immune to short-dura-
tion negative-going V
ing resets to the µP during power-up, power-down, and
brownout conditions. Therefore, resetting the µP when
V
ommended.
CC
(a)
experiences only small glitches is usually not rec-
Monitoring an Additional Power Supply
PFO
R1
R2
V
V
0V
V
TRIP
H
L
V
= (V
= R1 V
0V
IN
= V
Negative-Going V
PFT
PFT
PFT
+ V
______________________________________________________________________________________
(
R1 + R2
PFH
C1*
(
CC
R2
1
R1
) (R1)
TO µP
+
Bidirectional Reset Pins
)
transients (glitches) while issu-
1
R2
R3
(
Interfacing to µPs with
3.0V/3.3V Adjustable Microprocessor
1
R1
+
V
L
+
1
R3
PFI
PFO
1
R2
)
V
TRIP
+
–
V
R3
1
CC
R3
MAX793
MAX794
)
GND
V
WHERE
CC
V
CC
H
Transients
V
V
PFT
PFH
*OPTIONAL
= 1.237V
= 10mV
V
IN
(b)
Figure 17. Interfacing to µPs with Bidirectional Reset I/O
V
CC
GENERATOR
Supervisory Circuits
RESET
PFO
V
V
MAX793
MAX794
MAX795
TRIP
WHERE
H
R1
R2
V
GND
0V
CC
= R1 (V
V
= V
0V
IN
PFT
V
V
PFT
PFH
PFT
V
V
(
R1 + R2
D
L
RESET
+ V
= 1.237V
= DIODE FORWARD VOLTAGE DROP
= V
= 10mV
N
R2
C1*
TRIP
PFH
TO µP
)
)
(
R1
R3
1
V
+
TRIP
R2
PFI
PFO
1
+
1
R3
RESET
MAX793
MAX794
)
GND
V
–
CC
V
H
V
R3
D
V
µP
GND
CC
*OPTIONAL
IN
V
IN
17