Maxim MAX819LCSA, MAX819LCUA, MAX818MCSA, MAX818MCUA, MAX818MEPA 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 specif­ically designed to ignore fast transients on VCC. Other
supervisory functions include active-low reset, backup­battery 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

19-0494; Rev 1; 3/96

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.

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone]

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, Pin­Compatible Upgrades for:

MAX690A/
MAX692A

—

MAX703/

MAX704

Typical Operating Circuit appears at end of data sheet.

Pin Configurations continued at end of data sheet.

*Patents Pending

MAX817L/M, MAX818L/M, MAX819L/M*

+5V Microprocessor Supervisory Circuits

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +4.75V to +5.5V for MAX81_L, VCC= +4.5V to +5.5V for MAX81_M, V

BATT

= 2.8V, TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.)

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.

Note 1: The input voltage limits on PFI and WDI may be exceeded (up to 12V VIN) if the current into these pins is limited to less

than 10mA.

Input Voltage

V

CC

, BATT..........................................................-0.3V to +6.0V

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

CC

+ 0.3V)

Input Current

V

CC

Peak ..............................................................................1A

V

CC

Continuous .............................................................250mA

BATT Peak .....................................................................250mA

BATT Continuous.............................................................50mA

GND.................................................................................25mA

Output Current

OUT................................................................................250mA

All Other Outputs .............................................................25mA

OUT Short-Circuit Duration.................................................10sec

Continuous Power Dissipation (T

A

= +70°C)

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

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

µMAX (derate 4.10mW/°C above +70°C) .....................330mW

Operating Temperature Ranges

MAX81_ _C_A......................................................0°C to +70°C

MAX81_ _E_A ...................................................-40°C to +85°C

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

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

As applicable; CE IN = 0V,
WDI and MR unconnected

VCC< V

RST

I

OUT

= 50mA

I

OUT

= 5mA

VCC= 0V, V

OUT

= 0V

I

OUT

= 250µA, VCC< (V

BATT

- 0.2V)

CONDITIONS

mV40Battery Switchover Hysteresis

mV

-20

Battery Switch Threshold
(V

CC

- V

BATT

)

20

V

V

BATT -VBATT -

0.1 0.02

V

OUT

in Battery-Backup Mode

µA

11 60

I

SUPPLY

Supply Current (excluding I

OUT

)

11 45

V0 5.5

Operating Voltage Range, VCC,
V

BATT

(Note 2)

Ω100BATT to OUT On-Resistance

Ω510VCCto OUT On-Resistance

V

VCC- VCC-

0.5 0.25

V

OUT

Output

VCC- VCC-

0.05 0.025

µA

5.0

µA1

BATT Leakage Current,
Freshness Seal Enabled

UNITSMIN TYP MAXSYMBOLPARAMETER

VCC= 0V

Supply Current in Battery­Backup Mode (excluding I

OUT

)

0.05 1.0

MAX81_ _C
MAX81_ _E
TA= +25°C

TA= T

MIN

to

T

MAX

Power-up
Power-down

TA= +25°C
TA= T

MIN

to

T

MAX

5.5V > VCC> (V

BATT

+ 0.2V)BATT Standby Current (Note 3)

-0.10 0.02
µA

-1.00 0.02

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +4.75V to +5.5V for MAX81_L, VCC= +4.5V to +5.5V for MAX81_M, V

BATT

= 2.8V, TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.)

MAX817L/M, MAX818L/M, MAX819L/M*

+5V Microprocessor Supervisory Circuits

_______________________________________________________________________________________ 3

V

PFO

= 0V

V

PFI

> 1.30V, I

SOURCE

= 40µA, VCC> 4.5V

MAX81_M

V

PFI

< 1.20V, I

SINK

= 3.2mA, VCC> 4.50V

MAX81_L

WDI = GND, time average

From V

RST

, VCCfalling at 10V/ms

WDI = VCC, time average

VCC= 5V

MAX81_ _C, VCC= 1V, VCCfalling,
V

BATT

= 0V, I

SINK

= 50µA

VCC> V

RST(MAX), ISOURCE

= 800µA

VCC< V

RST(MIN), ISINK

= 3.2mA

VIL= 0.4V, VIH= 0.8V

CC

CONDITIONS

µA250 500

PFO Short-Circuit Current

VCC- 1.5V

OH

PFO Output Voltage

V

0.4V

OL

nA-25 0.01 25I

PFI

PFI Input Current

mV4PFI Input Hysteresis

V1.20 1.25 1.30V

PFT

PFI Input Threshold

µA

-20 -15

WDI Input Current (Note 5)

120 160

V

3.5V

IH

WDI Input Threshold (Note 4)

0.8V

IL

ns50t

WDI

WDI Pulse Width

V

4.25 4.40 4.50

V

RST

Reset Threshold

4.50 4.65 4.75

sec1.00 1.60 2.25t

WD

Watchdog Timeout Period

µs100

VCCto RESET Delay

0.3

mV25Reset Threshold Hysteresis
ms140 200 280t

RP

Reset Timeout Period

VCC- 1.5V

OH

0.4

V

OL

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX81_ _E, VCC= 1.2V, VCCfalling,
V

BATT

= 0V, I

SINK

= 100µA

V

0.3

RESET Output Voltage

0.8
V

2.0

V

IL

MR Input Threshold

µs1

MR Pulse Width

V

IH

ns100

MR Pulse that Would Not Cause
a Reset

ns120

MR to Reset Delay

kΩ45 63 85

MR Pull-Up Resistance

RESET AND WATCHDOG TIMER

POWER-FAIL COMPARATOR (MAX817/MAX819 only)

MANUAL RESET INPUT (MAX819 only)

MAX817L/M, MAX818L/M, MAX819L/M*

+5V Microprocessor Supervisory Circuits

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +4.75V to +5.5V for MAX81_L, VCC= +4.5V to +5.5V for MAX81_M, V

BATT

= 2.8V, TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.)

Power-down

VCC= 5V

I

OUT

= -1µA, VCC= 0V, V

BATT

= 2.8V

I

OUT

= -100µA, VCC= 0V

Enable mode

Disable mode

CONDITIONS

µs15

RESET to CE OUT Delay

3.5V

IL

CE OUT Input Threshold

V

0.8V

IH

V

2.7

V

OH

CE OUT Output

VCC- 1V

Ω40 150

CE IN to CE OUT Resistance
(Note 6)

µA±0.005 ±1

CE IN Leakage Current

UNITSMIN TYP MAXSYMBOLPARAMETER

Note 2: Either VCCor V

BATT

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

Note 3: “-” = battery-charging current, “+” = battery-discharging current.
Note 4: WDI is internally serviced within the watchdog timeout period if WDI is left unconnected.
Note 5: WDI input is designed to be driven by a three-stated output device. To float WDI, the “high-impedance mode” of the output

device must have a maximum leakage current of 10µA and a maximum output capacitance of 200pF. The output device
must also be able to source and sink at least 200µA when active.

Note 6: The chip-enable resistance is tested with V

CC

= +4.75V for the MAX818L and VCC= +4.5V for the MAX818M.

V

CE IN

= V

CE OUT

= VCC/2.

Note 7: The chip-enable propagation delay is measured from the 50% point at CE IN to the 50% point at CE OUT.

Disable mode, CE OUT = 0V

mA0.1 0.75 2.0

CE OUT Short-Circuit Current
(Reset Active)

50Ω source impedance driver, C

LOAD

= 50pF ns38

CE IN to CE OUT Propagation
Delay (Note 7)

CHIP-ENABLE GATING (MAX818 only)

MAX817L/M, MAX818L/M, MAX819L/M*

+5V Microprocessor Supervisory Circuits

_______________________________________________________________________________________

5

8

-40 40

SUPPLY CURRENT

vs. TEMPERATURE (NO LOAD)

12

MAX817/18/19-01

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

-20 0

20

80 10060

16

14

10

0

-40 40

BATTERY SUPPLY CURRENT

(BACKUP MODE) vs. TEMPERATURE

20

80

100

120

140

160

MAX817/18/19-02

TEMPERATURE (°C)

BATTERY SUPPLY CURRENT (nA)

-20 0 20 80 10060

60
40

VCC = 0V

V

BATT

= 5.0V

V

BATT

= 2.8V

V

BATT

= 2.0V

0

-40 40

CE IN TO CE OUT ON-RESISTANCE

vs. TEMPERATURE

20

80

MAX817/18/19-03

TEMPERATURE (°C)

CE IN TO CE OUT ON-RESISTANCE (Ω)

-20 0 20 80 10060

60

40

90

100

10

70

50

30

V

CE IN

= 4V

V

CE IN

= 3V

V

CE IN

= 2V

0

-40 40

BATT TO OUT ON-RESISTANCE

vs. TEMPERATURE

MAX817/18/19-04

TEMPERATURE (°C)

BATT TO OUT ON-RESISTANCE (Ω)

-20 0 20 80 10060

50

100

150

200

250

300

V

BATT

= 2.0V

V

BATT

= 2.8V

V

BATT

= 5.0V

V

CC

= 0V

0

-40 40

VCC TO RESET PROPAGATION DELAY

vs. TEMPERATURE

200

MAX817/18/19-07

TEMPERATURE (°C)

V

CC

TO RESET PROPAGATION DELAY (ms)

-20 0 20 80 10060

300

400

500

100

VCC FALLING AT:

0.25V/ms

1V/ms

10V/ms

3

-40 40

V

CC

TO OUT ON-RESISTANCE

vs. TEMPERATURE

MAX817/18/19-05

TEMPERATURE (°C)

V

CC

TO OUT ON-RESISTANCE (Ω)

-20 0 20 80 10060

4

5

6

7

180

-40 40

RESET TIMEOUT PERIOD

vs. TEMPERATURE

MAX817/18/19-06

TEMPERATURE (°C)

RESET TIMEOUT PERIOD (ms)

-20 0 20 80 10060

190

200

210

220

1.50

-40 40

WATCHDOG TIMEOUT PERIOD

vs. TEMPERATURE

1.60

MAX817/18/19-08

TEMPERATURE (°C)

WATCHDOG TIMEOUT PERIOD (sec)

-20 0 20 80 10060

1.65

1.70

1.55

0

-40 40

BATTERY FRESHNESS SEAL

LEAKAGE CURRENT vs. TEMPERATURE

10

MAX817/18/19-09

TEMPERATURE (°C)

LEAKAGE CURRENT (nA)

-20 0 20 80 10060

15

20

5

__________________________________________Typical Operating Characteristics

(VCC= +5V, V

BATT

= 3.0V, TA= +25°C, unless otherwise noted.)