Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Reset/power-on reset uMAX 8

19-4334; Rev. 9; 1/13

MAX705–MAX708/MAX813L

Low-Cost, µP Supervisory Circuits

For pricing, delivery, and ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

TOP VIEW

WDO

RESET (RESET)

WDI

PFO

PFI

GND

DIP/SO

MAX705

MAX706

MAX813L

RESET

N.C.

PFO

PFI

GND

DIP/SO

MAX707

MAX708

( ) ARE FOR MAX813L ONLY.

Pin Configurations continued at end of data sheet.

_________________Pin Configurations

PFI

PFO

WDO

RESET

UNREGULATED DC

PUSHBUTTON

SWITCH

PFI

I/O LINE

INTERRUPT

µP

MAX705

MAX706

MAX813L

MAX667

+5V DC LINEAR

REGULATOR

RESET

NMI

__________Typical Operating Circuit

_______________General Description

The MAX705-MAX708/MAX813L microprocessor (µP)

supervisory circuits reduce the complexity and number

of components required to monitor power-supply and

battery functions in µP systems. These devices signifi-

cantly improve system reliability and accuracy com-

pared to separate ICs or discrete components.

The MAX705/MAX706/MAX813L provide four functions:

1) A reset output during power-up, power-down, and

brownout conditions.

2) An independent watchdog output that goes low if

the watchdog input has not been toggled within 1.6

seconds.

3) A 1.25V threshold detector for power-fail warning,

low-battery detection, or for monitoring a power sup-

ply other than +5V.

4) An active-low manual-reset input.

The MAX707/MAX708 are the same as the MAX705/

MAX706, except an active-high reset is substituted for

the watchdog timer. The MAX813L is the same as the

MAX705, except RESET is provided instead of RESET.

Two supply-voltage monitor levels are available: The

MAX705/MAX707/MAX813L generate a reset pulse when

the supply voltage drops below 4.65V, while the

MAX706/MAX708 generate a reset pulse below 4.40V.

All four parts are available in 8-pin DIP, SO and µMAX

packages.

_______________________Applications

Computers

Controllers

Intelligent Instruments

Automotive Systems

Critical µP Power Monitoring

___________________________Features

o Available in Tiny µMAX Package

o Guaranteed RESET Valid at V

= 1V

o Precision Supply-Voltage Monitor

4.65V in MAX705/MAX707/MAX813L

4.40V in MAX706/MAX708

o 200ms Reset Pulse Width

o Debounced TTL/CMOS-Compatible

Manual-Reset Input

o Independent Watchdog Timer—1.6s Timeout

(MAX705/MAX706)

o Active-High Reset Output

(MAX707/MAX708/MAX813L)

o Voltage Monitor for Power-Fail or Low-Battery

Warning

______________Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX705CPA

8 Plastic DIP

MAX705CSA 0°C to +70°C 8 SO

MAX705C/D 0°C to +70°C Dice*

Ordering Information continued at end of data sheet.

Dice are specified at T

= +25°C.

Contact factory for availability and processing to MIL-STD-883.

Devices in PDIP, SO and µMAX packages 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.

Lead-free not available for CERDIP package.

0°C to +70°C

MAX705CUA 0°C to +70°C 8 µMAX

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Summary of content (12 pages)

PAGE 1
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits _______________General Description The MAX705-MAX708/MAX813L microprocessor (µP) supervisory circuits reduce the complexity and number of components required to monitor power-supply and battery functions in µP systems. These devices significantly improve system reliability and accuracy compared to separate ICs or discrete components.
PAGE 2
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits ABSOLUTE MAXIMUM RATINGS CERDIP (derate 8.00mW/°C above +70°C) . . . . . . . . . . 640mW Terminal Voltage (with respect to GND) Operating Temperature Ranges VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6.0V MAX70_C__, MAX813LC__ . . . . . . . . . . . . . . . . . . . . 0°C to +70°C All Other Inputs (Note 1) . . . . . . . . . . . . . . . -0.3V to (VCC + 0.3V) MAX70_E__, MAX813LE__ . . . . . . .
PAGE 3
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits ELECTRICAL CHARACTERISTICS (continued) (VCC = 4.75V to 5.5V for MAX705/MAX707/MAX813L, VCC = 4.5V to 5.5V for MAX706/MAX708, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER SYMBOL MR Pull-Up Current MR Pulse Width Low MR Input Threshold High MR to Reset Out Delay (Note 2) PFI Input Threshold CONDITIONS MR = 0V tMR TYP MAX UNITS 100 250 600 µA 150 ns 0.8 2.
PAGE 4
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits __________________________________________Typical Operating Characteristics MAX705/MAX707 RESET OUTPUT VOLTAGE vs. SUPPLY VOLTAGE POWER-FAIL COMPARATOR DE-ASSERTION RESPONSE TIME MAX705/MAX707 RESET RESPONSE TIME +5V 1V/div VCC +4V PFO +5V VCC GND RESET 330pF 1V/div RESET RESET VCC 2kΩ 1kΩ 30pF +3V +1.
PAGE 5
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits ______________________________________________________________Pin Description PIN MAX705/MAX706 MAX707/MAX708 DIP/SO DIP/SO µMAX µMAX MAX813L DIP/SO NAME FUNCTION µMAX 1 3 1 3 1 3 MR Manual-Reset Input triggers a reset pulse when pulled below 0.8V. This active-low input has an internal 250µA pull-up current. It can be driven from a TTL or CMOS logic line as well as shorted to ground with a switch.
PAGE 6
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits WDI 6 WATCHDOG TRANSITION DETECTOR VCC 250µA MR VCC 1 WATCHDOG TIMER WDO MR 7 RESET GENERATOR 2 RESET (RESET) RESET VCC 1 RESET GENERATOR 2 PFI 5 7 RESET MAX707 MAX708 4.65V* MAX705 MAX706 MAX813L 4 8 VCC 250µA TIMEBASE FOR RESET AND WATCHDOG 4.65V* PFI 8 4 5 PFO PFO 1.25V 1.25V * 4.40V FOR MAX7O6. ( ) ARE FOR MAX813L ONLY. 3 3 GND GND * 4.40V FOR MAX7O6. Figure 1. MAX705/MAX706/MAX813L Block Diagram Figure 2.
PAGE 7
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits Power-Fail Comparator The power-fail comparator can be used for various purposes because its output and noninverting input are not internally connected. The inverting input is internally connected to a 1.25V reference. tWP WDI tWD tWD tWD 0V When VCC falls below 1V, the MAX705-MAX708 RESET output no longer sinks current—it becomes an open circuit. High-impedance CMOS logic inputs can drift to undetermined voltages if left undriven.
PAGE 8
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits +12V +5V VCC 1MΩ 1% TO µP RESET MAX70_ MAX70_ MR 130kΩ 1% RESET PFI PFO GND R1 Figure 5. RESET Valid to Ground Circuit PARAMETER MIN TYP MAX UNIT +12V Reset Threshold at +25°C 10.67 10.87 11.50 V Figure 6. Monitoring Both +5V and +12V +5V BUFFERED RESET TO OTHER SYSTEM COMPONENTS 100kΩ VCC MR R1 MAX70_ 100kΩ 2N3904 PFO PFI VCC VCC MAX70_ µP 4.
PAGE 9
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits __Ordering Information (continued) PART TEMP RANGE MAX705EPA -40°C to +85°C 8 Plastic DIP MAX705ESA -40°C to +85°C 8 SO MAX705EUA -40°C to +85°C 8 µMAX MAX705MJA -55°C to +125°C 8 CERDIP** MAX706CPA 0°C to +70°C 8 Plastic DIP MAX706CSA 0°C to +70°C 8 SO MAX706CUA 0°C to +70°C 8 µMAX MAX706C/D 0°C to +70°C Dice* MAX706EPA -40°C to +85°C 8 Plastic DIP MAX706ESA -40°C to +85°C 8 SO MAX706EUA -40°C to +85°C 8 µMAX MAX706M
PAGE 10
TBD TBD TBD 1.2 TBD 10 6 10 6 TBD TBD ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 2.5 1.2 ✔ ✔ 10 6 10 6 1.2 VCC-to-VOUT On Resistance Max (Ω) ✔ ✔ ✔ ✔ ✔ ✔ Separate Watchdog Output Backup-Battery Switch Nominal Watchdog Timeout Period (sec), if Available –————– RESET Valid to VCC = 1V Active-High Reset Active-Low Reset Minimum Reset Pulse Width (ms) Nominal Reset Threshold (V) 4.37/4.62 250 ✔ ✔ ✔ 0.15/0.6/1.2 4.65/4.40 140 ✔ ✔ 1.6 2.63/2.93/3.08 140 ✔ ✔ 1.6 4.65/4.40 140/adj. ✔ ✔ ✔ 1.6/adj.
PAGE 11
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
PAGE 12
MAX705–MAX708/MAX813L Low-Cost, µP Supervisory Circuits Revision History REVISION NUMBER REVISION DATE 0 2/92 Initial release 8 3/10 Updated the Features, Absolute Maximum Ratings, Typical Operating Characteristics, Figures 3, 7, 8, and the Package Information sections.