19-0486; Rev 3; 12/05
+5V Microprocessor Supervisory Circuits
General Description
____________________________Features
♦ Precision Supply-Voltage Monitor:
4.65V (MAX81_L)
The MAX817/MAX818/MAX819 microprocessor (µP)
supervisory circuits simplify power-supply monitoring,
battery control, and chip-enable gating in µP systems
by reducing the number of components required.
These devices are designed for use in +5V-powered
systems. Low supply current (11µA typical) and small
package size make these devices ideal for portable
applications. The MAX817/MAX818/MAX819 are specif-
4.40V (MAX81_M)
♦ 11µA Quiescent Supply Current
♦ 200ms Reset Time Delay
♦ Watchdog Timer with 1.6sec Timeout
(MAX817/MAX818)
ically designed to ignore fast transients on V . Other
CC
♦ Battery-Backup Power Switching; Battery Voltage
supervisory functions include active-low reset, backup-
battery switchover, watchdog input, battery freshness
seal, and chip-enable gating. The Selector Guide below
lists the specific functions available from each device.
Can Exceed V
CC
♦ Battery Freshness Seal
♦ On-Board, 3ns Gating of Chip-Enable Signals
These devices offer two pretrimmed reset threshold volt-
ages for ±5ꢀ or ±1±ꢀ power suppliesꢁ :.45V for the L
versions and :.:±V for the M versions. The MAX817/
MAX818/MAX819 are available in space-saving µMAX
packages, as well as 8-pin DIP/SO.
(MAX818)
♦ Uncommitted Voltage Monitor for Power-Fail or
Low-Battery Warning (MAX817/MAX819)
♦ Manual Reset Input (MAX819)
______________Ordering Information
_____________________Selector Guide
†
PART
TEMP. RANGE
±°C to +7±°C
±°C to +7±°C
±°C to +7±°C
PIN-PACKAGE
8 Plastic DIP
8 SO
MAX817 MAX818 MAX819
FEATURE
MAX817_CPA
MAX817_CSA
MAX817_CUA
L/M
✔
L/M
✔
L/M
✔
Active-Low Reset
8 µMAX
✔
✔
✔
Backup-Battery Switchover
Power-Fail Comparator
Watchdog Input
Ordering Information continued on last page.
✔
✔
—
✔
✔
†
These parts offer a choice of reset threshold voltage. From the
table below, select the suffix corresponding to the desired
threshold and insert it into the blank to complete the part number.
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.
✔
—
✔
✔
✔
Battery Freshness Seal
Manual Reset Input
Chip-Enable Gating
—
—
—
✔
—
8-DIP/SO/ 8-DIP/SO/ 8-DIP/SO/
Pin-Package
µMAX
µMAX
µMAX
SUFFIX
RESET THRESHOLD (V)
L
:.45
:.:±
Low-Power, Pin-
Compatible Upgrades forꢁ MAX492A
MAX49±A/
MAX7±3/
MAX7±:
—
M
_________________Pin Configurations
________________________Applications
Battery-Powered Computers and Controllers
Embedded Controllers
TOP VIEW
1
2
3
4
8
7
6
5
BATT
RESET
WDI
OUT
Intelligent Instruments
V
CC
Critical µP Monitoring
MAX817
GND
PFI
Portable Equipment
PFO
Typical Operating Circuit appears at end of data sheet.
DIP/SO/µMAX
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.