MAX793SESE Datasheet, PDF (1/20 Pages) Maxim Integrated Products – 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits

19-0366; Rev 6; 3/10
3.0V/3.3V Adjustable Microprocessor
Supervisory Circuits
General Description
The MAX793/MAX794/MAX795 microprocessor (µP)
supervisory circuits monitor and control the activities of
+3.0V/+3.3V µPs by providing backup-battery switchover,
among other features such as low-line indication, µP
reset, write protection for CMOS RAM, and a watchdog
(see the Selector Guide below). The backup-battery volt-
age can exceed V_CC, permitting the use of 3.6V lithium
batteries in systems using 3.0V to 3.3V for V_CC.
The MAX793/MAX795 offer a choice of reset threshold
voltage range (denoted by suffix letter): 3.00V to 3.15V
(T), 2.85V to 3.00V (S), and 2.55V to 2.70V (R). The
MAX794’s reset threshold is set externally with a resistor
divider. The MAX793/MAX794 are available in 16-pin
DIP and narrow SO packages, and the MAX795 comes
in 8-pin DIP and SO packages.
_____________________Selector Guide
FEATURE
Active-Low Reset
Active-High Reset
Programmable Reset
Threshold
Low-Line Early Warning
Output
Backup-Battery
Switchover
External Switch Driver
Power-Fail Comparator
Battery OK Output
Watchdog Input
Battery Freshness Seal
Manual Reset Input
Chip-Enable Gating
Pin-Package
MAX793


MAX794


MAX795




















16-DIP/SO 16-DIP/SO


8-DIP/SO
________________________Applications
Battery-Powered Computers and Controllers
Embedded Controllers
Intelligent Controllers
Critical µP Power Monitoring
Portable Equipment
Pin Configurations appear at end of data sheet.
____________________________Features
MAX793/MAX794/MAX795
o Precision Supply-Voltage Monitor:
Fixed Reset Trip Voltage (MAX793/MAX795)
Adjustable Reset Trip Voltage (MAX794)
o Guaranteed Reset Assertion to V_CC = 1V
o Backup-Battery Power Switching—Battery
Voltage Can Exceed V_CC
o On-Board Gating of Chip-Enable Signals—7ns
Max Propagation Delay
MAX793/MAX794 Only
o Battery Freshness Seal
o Battery OK Output (MAX793)
o Uncommitted Voltage Monitor for Power-Fail or
Low-Battery Warning
o Independent Watchdog Timer (1.6s timeout)
o Manual Reset Input
Ordering Information
PART*
TEMP RANGE
PIN-
PACKAGE
MAX793_CPE
MAX793_CSE
0°C to +70°C
0°C to +70°C
16 Plastic DIP
16 Narrow SO
Ordering Information continued at end of data sheet.
*The MAX793/MAX795 offer a choice of reset threshold voltage.
Select the letter corresponding to the desired reset threshold
voltage range (T = 3.00V to 3.15V, S = 2.85V to 3.00V, R =
2.55V to 2.70V) and insert it into the blank to complete the part
number. The MAX794’s reset threshold is adjustable.
Devices are available in both leaded and lead-free packaging.
Specify lead free by adding the + symbol at the end of the part
number when ordering.
__________Typical Operating Circuit
3.0V OR 3.3V
0.1µF
3.6V
0.1µF
+5V SUPPLY
+5V ^FAILURE
(OPTIONAL)
Si9433DY
SILICONIX
PMOS
V_CC BATT ON OUT
BATT
CE OUT
0.1µF
CMOS
RAM
MAX793
WDO
CE IN
MR
WDI
PFO
LOWLINE
ADDRESS
DECODER
V_CC
V_CC
A0-A15
I/O
NMI
µP
PFI
RESET
BATT OK
GND
RESET
________________________________________________________________ Maxim Integrated Products 1
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