Datasheet
General Description
The MAX696/MAX697 supervisory circuits reduce the
complexity and number of components required for
power-supply monitoring and battery-control functions
in microprocessor (μP) systems. These include μP reset
and backup-battery switchover, watchdog timer, CMOS
RAM write protection, and power-failure warning. The
MAX696/MAX697 significantly improve system reliability
and accuracy compared to that obtained with separate
ICs or discrete components.
The MAX696 and MAX697 are supplied in 16-pin pack-
ages and perform six functions:
1) A reset output during power-up, power-down, and
brownout conditions. The threshold for this “lowline”
reset is adjustable by an external voltagedivider.
2) A reset pulse if the optional watchdog timer has not
been toggled within a specified time.
3) Individual outputs for low-line and watchdog fault con-
ditions.
4) The reset time may be left at its default value of 50ms,
or may be varied with an external capacitor or clock
pulses.
5) A separate 1.3V threshold detector for power-fail warn-
ing, low-battery detection, or to monitor a power supply
other than V
CC
.
The MAX696 also has battery-backup switching for CMOS
RAM, CMOS microprocessor, or other lowpower logic.
The MAX697 lacks battery-backup switching, but has
write-protection pins (CE IN and CE OUT) for CMOS
RAM or EPROM. In addition, it consumes less than 250
microamperes.
Applications
● Computers
● Controllers
● Intelligent Instruments
● Critical μP Power Monitoring
Features
● Adjustable Low-Line Monitor and Power-Down Reset
● Power-OK/Reset Time Delay
● Watchdog Timer—100ms, 1.6s, or Adjustable
● Minimum Component Count
● 1μA Standby Current
● Battery-Backup Power Switching (MAX696)
● On-Board Gating of Chip-Enable Signals (MAX697)
● Separate Monitor for Power-Fail or Low-Battery
Warning
Typical Operating Circuit appears at end of data sheet.
Pin Configurations continued at end of data sheet.
Ordering Information continued at end of data sheet.
19-0829; Rev 5; 7/14
Devices in PDIP and SO packages are available in both leaded
and lead(Pb)-free packaging. Specify lead free by adding the +
symbol at the end of the part number when ordering. Lead free
not available for CERDIP package.
PART TEMP RANGE PIN-PACKAGE
MAX696C/D 0°C to +70°C Dice
MAX696CPE 0°C to +70°C 16 PDIP
MAX696CWE 0°C to +70°C 16 Wide SO
MAX696EPE -40°C to +85°C 16 PDIP
MAX696EJE -40°C to +85°C 16 CERDIP
MAX696EWE -40°C to +85°C 16 Wide SO
MAX696MJE -55°C to +125°C 16 CERDIP
V
OUT
V
BATT
V
CC
GND
LLIN
1
2
3
4
16
15
14
13
N.C.
BATT ON
PFI
WDI
5
6
7
8
12
11
10
9
OSC IN
OSC SEL
PFO
LOW LINE
TOP VIEW
RESET
RESET
WDO
MAX696
MAX696/MAX697 Microprocessor Supervisory Circuits
Ordering Information
Pin Congurations