Maxim MAX805LCSA, MAX805LESA, MAX805LMJA, MAX805LC-D, MAX802MEPA Datasheet

19-4333; Rev 3; 9/93

RESET

Microprocessor Supervisory Circuits

__________________General Description

The MAX690A/MAX692A/MAX802L/MAX802M/MAX805L
reduce the complexity and number of components
required for power-supply monitoring and battery-control
functions in microprocessor (µP) systems. They signifi­cantly improve system reliability and accuracy compared
to separate ICs or discrete components.

These parts provide four functions:

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

2) Battery-backup switching for CMOS RAM, CMOS
µP, or other low-power logic.

3) A reset pulse if the optional watchdog timer has not
been toggled within 1.6sec.

4) A 1.25V threshold detector for power-fail warning or
low-battery detection, or to monitor a power supply
other than +5V.

The parts differ in their reset-voltage threshold levels
and reset outputs. The MAX690A/MAX802L/MAX805L
generate a reset pulse when the supply voltage drops
below 4.65V, and the MAX692A/MAX802M generate a
reset below 4.40V. The MAX802L/MAX802M guaran­tee power-fail accuracies to ±2%. The MAX805L is the
same as the MAX690A except that RESET is provided
instead of RESET.

All parts are available in 8-pin DIP and SO packages.
The MAX690A/MAX802L are pin compatible with the
MAX690 and MAX694. The MAX692A/MAX802M are
pin compatible with the MAX692.

_______________________Applications

Battery-Powered Computers and Controllers
Intelligent Instruments
Automotive Systems
Critical µP Power Monitoring

__________Typical Operating Circuit

UNREGULATED DC REGULATED +5V

V

O.1µF

R

1

3.6V

R

2

LITHIUM
BATTERY

PFI

V

MAX690A
MAX802L

V

BATT

CC

RESET

PFO
WDI

V

OUT

GND

CC

RESET
NMI

I/O LINE

BUS

V

CC

CMOS

RAM

µP

GND

GND

___________________________Features

♦ Precision Supply-Voltage Monitor:

4.65V for MAX690A/MAX802L/MAX805L

4.40V for MAX692A/MAX802M

♦ Reset Time Delay – 200ms
♦ Watchdog Timer – 1.6sec Timeout
♦ Battery-Backup Power Switching
♦ 200µA Quiescent Supply Current
♦ 50nA Quiescent Supply Current in Battery-

Backup Mode

♦ Voltage Monitor for Power-Fail or Low-Battery

Warning

♦ Power-Fail Accuracy Guaranteed to ±2%

(MAX802L/M)

♦ Guaranteed
♦ 8-Pin SO and DIP Packages

Assertion to VCC= 1V

______________Ordering Information

PART TEMP. RANGE PIN-PACKAGE

MAX690ACPA

MAX690ACSA 0°C to +70°C 8 SO
MAX690AC/D 0°C to +70°C Dice*
MAX690AEPA -40°C to +85°C 8 Plastic DIP
MAX690AESA -40°C to +85°C 8 SO
MAX690AMJA -55°C to +125°C 8 CERDIP**

Ordering Information continued on last page.

* Dice are specified at T
**Contact factory for availability and processing to MIL-STD-883.

0°C to +70°C

= +25°C

A

8 Plastic DIP

_________________Pin Configurations

TOP VIEW

V

OUT

1

PFI

MAX690A

2

CC

MAX692A
MAX802L

3

MAX802M

4

MAX805L

DIP/SO

V

GND

( ) ARE FOR MAX805L ONLY.

8

BATT

V
RESET (RESET)

7

WDI

6
5

PFO

MAX690A/MAX692A/MAX802L/MAX802M/MAX805L

________________________________________________________________

Maxim Integrated Products

Call toll free 1-800-998-8800 for free samples or literature.

1

Microprocessor Supervisory Circuits

ABSOLUTE MAXIMUM RATINGS

Terminal Voltage (with respect to GND)

............................................... -0.3V to 6.0V

V

CC

.............................................. -0.3V to 6.0V

V

BATT

All Other Inputs (Note 1) ................ -0.3V to (V

Input Current

...................................................... 200mA

V

CC

..................................................... 50mA

V

BATT

GND ...................................................... 20mA

Output Current

................... Short-Circuit Protected for up to 10sec

V

OUT

All Other Outputs ........................................ 20mA

CC

+ 0.3V)

Note 1: The input voltage limits on PFI and WDI may be exceeded if the current into these pins is limited to less than 10mA.

Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

ELECTRICAL CHARACTERISTICS

(VCC= 4.75V to 5.5V for MAX690A/MAX802L/MAX805L, VCC= 4.5V to 5.5V for MAX692A/MAX802M, V

= T

to T

T

A

MIN

Operating Voltage Range,

, V

V

CC

BATT

Supply Current (Excluding I

I

SUPPLY

(Excluding I

V

Standby Current (Note 3)

BATT

V

Output

OUT

V

in Battery-Backup Mode I

OUT

Battery Switch Threshold, V
to V

BATT

Battery Switchover Hysteresis 40 mV

Reset Threshold

Reset Threshold Hysteresis 40 mV
Reset Pulse Width

MAX690A/MAX692A/MAX802L/MAX802M/MAX805L

RESET Output Voltage

, unless otherwise noted.)

MAX

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

MAX69_AC, MAX802_C 1.0 5.5

(Note 2)

OUT

in Battery-Backup Mode

)

OUT

) I

SUPPLY

MAX69_AE/M, MAX80_ _E 1.2 5.5
MAX69_AC, MAX802_C 200 350
MAX69_AE/M, MAX802_E, MAX805LE/M 200 500
VCC= 0V,

V

BATT

5.5V > VCC>
V

BATT

I

= 5mA VCC- 0.05 VCC- 0.025

OUT

I

= 50mA

OUT

= 250µA, VCC< V

OUT

CC

VCC< V

MAX690A, MAX802L, MAX805L
MAX692A, MAX802M 4.25 4.40 4.50

V

RT

MAX802L, TA= +25°C, VCCfalling
MAX802M, TA= +25°C, VCCfalling

t

RS

I

SOURCE

I

= 3.2mA

SINK

MAX69_AC, MAX802_C, VCC= 1.0V

= 50µA

I

SINK

MAX69_AE/M, MAX802_E,

= 1.2V, I

V

CC

Rate of Rise, V
Continuous Power Dissipation

, V

CC

................................ 100V/µs

BATT

Plastic DIP (derate 9.09mW/°C above +70°C) ........ 727mW

SO (derate 5.88mW/°C above +70°C) ................ 471mW

CERDIP (derate 8.00mW/°C above +70°C) ........... 640mW

Operating Temperature Ranges:

MAX69_AC_ _, MAX80_ _ C_ _ .................. 0°C to +70°C

MAX69_AE_ _, MAX80_ _ E_ _ ................ -40°C to +85°C

MAX69_AMJA, MAX805LMJA................ -55°C to +125°C

Storage Temperature Range .................. -65°C to +160°C

Lead Temperature (soldering, 10sec) .................. +300°C

1.1 5.5

= 2.8V

+0.2V

TA= +25°C
TA= T

MIN

TA= +25°C
TA= T

MIN

to T

to T

MAX

MAX

0.05 1.0

-0.1 0.02

-1.0 0.02

VCC- 0.5 VCC- 0.25

- 0.2V V

BATT

RT

Power-up
Power-down

BATT

- 0.1 V

BATT

20

-20

4.50 4.65 4.75

4.55 4.70

4.30 4.45

140 200 280 ms

= 800µA VCC- 1.5

= 100µA

SINK

- 0.02

5.0

0.4

0.3

0.3

BATT

= 2.8V,

VMAX805LC

µA

µA

µA

V
V

mV

V

V

2 _______________________________________________________________________________________

Microprocessor Supervisory Circuits

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 4.75V to 5.5V for MAX690A/MAX802L/MAX805L, VCC= 4.5V to 5.5V for MAX692A/MAX802M, V

= T

to T

T

A

MIN

, unless otherwise noted.)

MAX

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

RESET Output Voltage

Watchdog Timeout
WDI Pulse Width

WDI Input Threshold (Note 4)

WDI Input Current

PFI Input Threshold

MAX805LC, I
MAX805LE/M, I
MAX805L, I
MAX805L, I

t

WD

t

VIL= 0.4V, VIH= (0.8) (VCC)

WP

VCC= 5V
WDI = V

CC

WDI = 0V -150 -50
MAX69_A, MAX805L, VCC= 5V
MAX802_C/E, VCC= 5V

= 4µA, VCC= 1.1V

SOURCE

SOURCE
SINK

= 4µA, VCC= 1.2V

SOURCE

= 800µA VCC- 1.5

= 3.2mA

Logic low
Logic high

0.8

0.9

1.00 1.60 2.25 sec
50 ns

3.5
50 150

1.20 1.25 1.30

1.225 1.250 1.275

PFI Input Current -25 0.01 25 nA

I

= 800µA VCC- 1.5

PFO Output Voltage

Note 2: Either VCCor V
Note 3: "-" = battery-charging current, "+" = battery-discharging current.

can go to 0V, if the other is greater than 2.0V.

BATT

Note 4: WDI is guaranteed to be in an intermediate, non-logic level state if WDI is floating and V

WDI is internally biased to 35% of V

SOURCE

I

= 3.2mA

SINK

with an input impedance of 50kΩ.

CC

is in the operating voltage range.

CC

BATT

0.4

0.8

0.4

MAX690A/MAX692A/MAX802L/MAX802M/MAX805L

= 2.8V,

V

V

µA

V

V

_______________________________________________________________________________________ 3

Microprocessor Supervisory Circuits

__________________________________________Typical Operating Characteristics

5.00

4.95

4.90

(V)

OUT

V

4.85

4.80

4.75

RESET

+5V
V

+5V

0

CC

V

CC

OUTPUT VOLTAGE

vs. LOAD CURRENT

VCC = +5V

= +2.8V

V

BATT

= +25°C

T

A

SLOPE = 5Ω

20

10 30 50

I

OUT



MAX690A

RESET RESPONSE TIME

V

CC

10k

RESET

30pF

GND

2µs/div

40

(mA)

TA = +25°C

RESET

+4V

1V/div

0V

2.80

2.78

2.76

(V)

OUT

V

2.74

2.72

2.70

+1.30V

SLOPE = 80Ω

0

0.2 0.6 1.0

POWER-FAIL COMPARATOR

+5V

PFO

PFI

+1.25V

PFI

OUTPUT VOLTAGE

vs. LOAD CURRENT

0.4
I

(mA)

OUT



RESPONSE TIME

+5V

1k

PFO

30pF

VCC = +5V

= +25°C

T

A

400ns/div

VCC = 0V
V

BATT

= +25°C

T

A

= +2.8V

0.8

+0V

+1.2V

V

CC

0V

RESET

0V

PFO

PFI

+1.20V

RESET OUTPUT VOLTAGE

vs. SUPPLY VOLTAGE

V

CC

POWER-FAIL COMPARATOR

PFI

+1.25V

0V

MAX690A

V

= OV

BATT

TA = +25°C

V

CC

RESET

GND

500ms/div



RESPONSE TIME

+5V

PFO

30pF 1k

400ns/div

2k

RESET

330pF

VCC = +5V
T

= +25°C

A

+5V
1V/div

+5V
1V/div

+3V

+1.3V



MAX805L

RESET OUTPUT VOLTAGE

vs. SUPPLY VOLTAGE

V

CC

V

0V

MAX690A/MAX692A/MAX802L/MAX802M/MAX805L

RESET

0V

V

BATT 

RESET 



GND

CC 





500ms/div

10k

330

pF

+5V

1V/div

+5V

1V/div

+5V
V

CC

RESET

0V

0V

RESET RESPONSE TIME

V

CC

GND

MAX805L

10k



+4V

330pF

+4V

2µs/div

4 _______________________________________________________________________________________