Datasheet
General Description
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-
ically designed to ignore fast transients on V
CC
. Other
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.
These devices offer two pretrimmed reset threshold volt-
ages for ±5% or ±10% power supplies: 4.65V for the L
versions and 4.40V for the M versions. The MAX817/
MAX818/MAX819 are available in space-saving µMAX
packages, as well as 8-pin DIP/SO.
________________________Applications
Battery-Powered Computers and Controllers
Embedded Controllers
Intelligent Instruments
Critical µP Monitoring
Portable Equipment
____________________________Features
♦ Precision Supply-Voltage Monitor:
4.65V (MAX81_L)
4.40V (MAX81_M)
♦ 11µA Quiescent Supply Current
♦ 200ms Reset Time Delay
♦ Watchdog Timer with 1.6sec Timeout
(MAX817/MAX818)
♦ Battery-Backup Power Switching; Battery Voltage
Can Exceed V
CC
♦ Battery Freshness Seal
♦ On-Board, 3ns Gating of Chip-Enable Signals
(MAX818)
♦ Uncommitted Voltage Monitor for Power-Fail or
Low-Battery Warning (MAX817/MAX819)
♦ Manual Reset Input (MAX819)
MAX817L/M, MAX818L/M, MAX819L/M*
+5V Microprocessor Supervisory Circuits
________________________________________________________________ Maxim Integrated Products 1
WDI
GND
PFO
PFI
1
2
8
7
BATT
RESET
V
CC
OUT
MAX817
DIP/SO/µMAX
TOP VIEW
3
4
6
5
_________________Pin Configurations
19-0486; Rev 3; 12/05
PART
†
MAX817_CPA
MAX817_CSA
MAX817_CUA 0°C to +70°C
0°C to +70°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
8 Plastic DIP
8 SO
8 µMAX
______________Ordering Information
_____________________Selector Guide
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.
SUFFIX RESET THRESHOLD (V)
L 4.65
M 4.40
FEATURE
MAX817
L/M
Active-Low Reset
✔
Backup-Battery Switchover
✔
MAX818
L/M
✔
✔
MAX819
L/M
✔
✔
Power-Fail Comparator
✔
—
Watchdog Input
✔ ✔
✔
—
Battery Freshness Seal
✔ ✔
Manual Reset Input — —
✔
✔
Chip-Enable Gating —
✔
Pin-Package
8-DIP/SO/
µMAX
8-DIP/SO/
µMAX
—
8-DIP/SO/
µMAX
Low-Power, Pin-
Compatible Upgrades for:
MAX690A/
MAX692A
—
MAX703/
MAX704
Typical Operating Circuit appears at end of data sheet.
Pin Configurations continued at end of data sheet.
*P
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.