MAX6731UTTD3+T全新原装原理图各脚功能电路原理芯片引脚定义-中国IC网-芯三七

19-2629; Rev 2; 1/03

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

General Description

Features

ꢀ V 1 (Primary Supply) Reset Threshold Voltages

The MAX6730–MAX6735 single-/dual-/triple-voltage

microprocessor (µP) supervisors feature a watchdog

timer and manual reset capability. The MAX6730–

MAX6735 offer factory-set reset thresholds for monitor-

ing voltages from +0.9V to +5V and an adjustable reset

input for monitoring voltages down to +0.63V. The com-

bination of these features significantly improves system

reliability and accuracy when compared to separate

ICs or discrete components.

CC

from +1.575V to +4.63V

ꢀ V 2 (Secondary Supply) Reset Threshold

CC

Voltages from +0.79V to +3.08V

ꢀ Adjustable RSTIN Threshold for Monitoring

Voltages Down to +0.63V (MAX6734/MAX6735 Only)

ꢀ Six Reset Timeout Options

ꢀ Watchdog Timer with Independent Watchdog Output

35s (min) Initial Watchdog Startup Period

The active-low reset output asserts and remains asserted

for the reset timeout period after all the monitored volt-

ages exceed their respective thresholds. Multiple factory-

set reset threshold combinations reduce the number of

external components required. The MAX6730/MAX6731

monitor a single fixed voltage, the MAX6732/MAX6733

monitor two fixed voltages, and the MAX6734/MAX6735

monitor two fixed voltages and one adjustable voltage. All

devices are offered with six minimum reset timeout peri-

ods ranging from 1.1ms to 1120ms.

1.12s (min) Normal Watchdog Timeout Period

ꢀ Manual Reset Input

(MAX6730/MAX6731/MAX6734/MAX6735)

ꢀ Guaranteed Reset Valid down to

V

1 or V 2 = +0.8V

CC

ꢀ Push-Pull RESET or Open-Drain RESET Output

ꢀ Immune to Short V Transients

CC

The MAX6730–MAX6735 feature a watchdog timer with

an independent watchdog output. The watchdog timer

prevents system lockup during code execution errors.

A watchdog startup delay of 54s after reset asserts

allows system initialization during power-up. The watch-

dog operates in normal mode with a 1.68s delay after

initialization. The MAX6730/MAX6732/MAX6734 provide

an active-low, open-drain watchdog output. The

MAX6731/MAX6733/MAX6735 provide an active-low,

push-pull watchdog output.

ꢀ Low Supply Current: 14µA (typ) at +3.6V

ꢀ Small 6-Pin and 8-Pin SOT23 Packages

Ordering Information

PART*

TEMP RANGE

-40°C to +85°C

PIN-PACKAGE

6 SOT23-6

8 SOT23-8

MAX6730UT_D_ -T

MAX6731UT_D_ -T

MAX6732UT_ _D_ -T

MAX6733UT_ _D_ -T

MAX6734KA_ _D_ -T

MAX6735KA_ _D_ -T

Other features include a manual reset input (MAX6730/

MAX6731/MAX6734/MAX6735) and push-pull reset out-

put (MAX6731/MAX6733/MAX6735) or open-drain reset

output (MAX6730/MAX6732/MAX6734). The MAX6730–

MAX6733 are offered in a tiny SOT23-6 package. The

MAX6734/MAX6735 are offered in a space-saving

SOT23-8 package. All devices are fully specified over

the extended temperature range (-40°C to +85°C).

*Note: Insert the threshold level suffixes for V 1 and V

2

CC

(Table 1) after “UT” or “KA.” For the MAX6730/MAX6731, insert

Applications

only the V 1 threshold suffix after the “UT.” Insert the reset

CC

timeout delay (Table 2) after “D” to complete the part number.

Multivoltage Systems

Telecom/Networking Equipment

Computers/Servers

For example, the MAX6732UTLTD3-T provides a V 1 threshold

CC

of +4.625V, a V 2 threshold of +3.075V, and a 210ms reset

CC

timeout period. Sample stock is generally held on standard ver-

sions only (see the Standard Versions table). Standard versions

have an order increment requirement of 2500 pieces.

Nonstandard versions have an order increment requirement of

10,000 pieces. Contact factory for availability.

Portable/Battery-Operated Equipment

Industrial Equipment

Printer/Fax

Set-Top Boxes

Typical Operating Circuit and Pin Configurations appear 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.

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

ABSOLUTE MAXIMUM RATINGS

Operating Temperature Range ...........................-40°C to +85°C

Storage Temperature Range.............................-65°C to +150°C

Junction Temperature......................................................+150°C

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

V

1, V 2, RSTIN, MR, WDI to GND.....................-0.3V to +6V

CC

RST, WDO to GND (open drain)...............................-0.3V to +6V

RST, WDO to GND (push-pull).................-0.3V to (V 1 + 0.3V)

Input Current/Output Current (all pins) ...............................20mA

CC

Continuous Power Dissipation (T = +70°C)

A

6-Pin SOT23-6 (derate 8.7mW/°C above +70°C) ........696mW

8-Pin SOT23-8 (derate 8.9mW/°C above +70°C) ........714mW

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

(V 1 = V 2 = +0.8V to +5.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)

A

CC

PARAMETER

SYMBOL

1,

CONDITIONS

MIN

TYP

MAX

UNITS

V

CC

Supply Voltage

0.8

5.5

V

2

CC

V

1 < +5.5V, all I/O connections

CC

15

10

4

39

28

11

9

open, outputs not asserted

I

1

CC

V

1 < +3.6V, all I/O connections

CC

open, outputs not asserted

Supply Current

µA

V

2 < +3.6V, all I/O connections

CC

open, outputs not asserted

2

CC

V

2 < +2.75V, all I/O connections

CC

3

open, outputs not asserted

L (falling)

4.500

4.250

3.000

2.850

2.550

2.250

2.125

1.620

1.530

4.625

4.375

3.075

2.925

2.625

2.313

2.188

1.665

1.575

4.750

4.500

3.150

3.000

2.700

2.375

2.250

1.710

1.620

M (falling)

T (falling)

S (falling)

V

1 Reset Threshold

CC

V

1

TH

R (falling)

V

Z (falling)

Y (falling)

W (falling)

V (falling)

2

_______________________________________________________________________________________

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

ELECTRICAL CHARACTERISTICS (continued)

(V 1 = V 2 = +0.8V to +5.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)

A

CC

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

3.150

3.000

2.700

2.375

2.250

1.710

1.620

1.425

1.350

1.140

1.080

0.855

0.810

UNITS

T (falling)

S (falling)

R (falling)

Z (falling)

Y (falling)

W (falling)

V (falling)

I (falling)

H (falling)

G (falling)

F (falling)

E (falling)

D (falling)

3.000

2.850

2.550

2.250

2.125

1.620

1.530

1.350

1.275

1.080

1.020

0.810

0.765

3.075

2.925

2.625

2.313

2.188

1.665

1.575

1.388

1.313

1.110

1.050

0.833

0.788

20

V

2 Reset Threshold

V

2

TH

V

CC

Reset Threshold Tempco

Reset Threshold Hysteresis

ppm/^oC

%

V

Referenced to V typical

0.5

HYST

TH

V

1 = (V 1 + 100mV) to

CC TH

(V 1 - 100mV) or

TH

V

_ to RST Output Delay

CC

t

45

µs

RD

V

2 = (V 2 + 75mV) to

CC TH

(V 2 - 75mV)

TH

D1

D2

D3

D5

D6

D4

1.1

8.8

1.65

13.2

210

2.2

17.6

280

140

280

560

1120

Reset Timeout Period

t

RP

ms

420

560

840

1120

2240

1680

ADJUSTABLE RESET COMPARATOR INPUT (MAX6734/MAX6735)

RSTIN Input Threshold

RSTIN Input Current

V

611

-25

626.5

642

+25

mV

nA

mV

µs

RSTIN

I

RSTIN Hysteresis

3

RSTIN to Reset Output Delay

t

V

to (V - 30mV)

RSTIN

22

RSTIND

RSTIN

MANUAL RESET INPUT (MAX6730/MAX6731/MAX6734/MAX6735)

V

0.3 × V

1

CC

IL

MR Input Threshold

V

0.7 × V

1

CC

IH

MR Minimum Pulse Width

MR Glitch Rejection

1

µs

ns

kΩ

100

200

50

MR to Reset Output Delay

MR Pullup Resistance

t

MR

25

80

_______________________________________________________________________________________

3

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

ELECTRICAL CHARACTERISTICS (continued)

(V 1 = V 2 = +0.8V to +5.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)

A

CC

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

WATCHDOG INPUT

First watchdog period after reset

timeout period

t

35

54

72

WD-L

Watchdog Timeout Period

s

t

Normal mode

(Note 2)

1.12

50

1.68

2.24

WD-S

WDI Pulse Width

WDI Input Voltage

t

ns

V

WDI

V

0.3 × V

1

CC

IL

V

0.7 × V

1

CC

IH

WDI Input Current

I

WDI = 0 or V

1

CC

-1

+1

µA

WDI

RESET/WATCHDOG OUTPUT

V

1 or V 2 ≥ +0.8V,

CC

= 1µA, output asserted

CC

0.3

0.4

I

SINK

V

1 or V 2 ≥ +1.0V,

CC CC

I

= 50µA, output asserted

SINK

V

1 or V 2 ≥ +1.2V,

RST/WDO Output Low Voltage

(Push-Pull or Open Drain)

CC

V

OL

I

= 100µA, output asserted

SINK

V

1 or V 2 ≥ +2.7V,

CC CC

I

= 1.2mA, output asserted

SINK

V

1 or V 2 ≥ +4.5V,

CC CC

I

= 3.2mA, output asserted

SINK

V

1 ≥ +1.8V, I

= 200µA,

= 500µA,

= 800µA,

CC

SOURCE

0.8 × V

1

CC

output not asserted

V 1 ≥ +2.7V, I

CC

RST/WDO Output High Voltage

(Push-Pull Only)

SOURCE

V

OH

output not asserted

V

1 ≥ +4.5V, I

CC

SOURCE

output not asserted

RST/WDO Output Open-Drain

Leakage Current

Output not asserted

0.5

µA

Note 1: Devices tested at T = +25°C. Overtemperature limits are guaranteed by design and not production tested.

A

Note 2: Parameter guaranteed by design.

4

_______________________________________________________________________________________

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Typical Operating Characteristics

(V 1 = +5V, V 2 = +3.3V, T = +25°C, unless otherwise noted.)

CC

A

SUPPLY CURRENT vs. TEMPERATURE

(V 1 = +5V, V 2 = +3.3V)

SUPPLY CURRENT vs. TEMPERATURE

(V 1 = +3.3V, V 2 = +2.5V)

(V 1 = +2.5V, V 2 = +1.8V)

CC

18

16

14

12

10

8

18

16

14

12

10

8

16

14

12

10

8

TOTAL

I

1

CC

TOTAL

I

1

CC

I

1

2

CC

6

4

I

2

4

CC

I

2

CC

I

CC

2

0

-40

-15

10

35

60

85

-40

-15

10

35

60

85

-40

-15

10

35

60

85

TEMPERATURE (°C)

SUPPLY CURRENT vs. TEMPERATURE

NORMALIZED THRESHOLD VOLTAGE

vs. TEMPERATURE

(V 1 = +1.8V, V 2 = +1.2V)

CC

1.010

18

16

14

12

10

8

1.008

1.006

1.004

1.002

1.000

0.998

0.996

0.994

0.992

0.990

TOTAL

6

I

1

CC

4

2

0

-40

-15

10

35

60

85

-40

-15

10

35

60

85

TEMPERATURE (°C)

_______________________________________________________________________________________

5

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Typical Operating Characteristics (continued)

(V 1 = +5V, V 2 = +3.3V, T = +25°C, unless otherwise noted.)

CC

A

NORMALIZED TIMEOUT PERIOD

vs. TEMPERATURE

MAXIMUM V

vs. RESET THRESHOLD OVERDRIVE

TRANSIENT DURATION

CC_

MR TO RESET OUTPUT DELAY

MAX6730-35 toc08

1.0040

10,000

1000

100

1.0035

1.0030

1.0025

1.0020

1.0015

1.0010

1.0005

1.0000

0.9995

0.9990

RST ASSERTS

ABOVE THIS LINE

MR

2V/div

RST

2V/div

10

-40

-15

10

35

60

85

1

10

100

1000

TEMPERATURE (°C)

40ns/div

RESET THRESHOLD OVERDRIVE (mV)

V

TO RESET OUTPUT DELAY

RSTIN TO RESET OUTPUT DELAY

vs. TEMPERATURE

CC_

vs. TEMPERATURE (100mV OVERDRIVE)

80

75

70

65

60

55

50

45

40

30

28

26

24

22

20

18

16

14

12

10

-45

-15

10

35

60

85

-45

-15

10

35

60

85

TEMPERATURE (°C)

6

_______________________________________________________________________________________

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Pin Description

NAME

FUNCTION

MAX6730

MAX6731

MAX6732

MAX6733

MAX6734

MAX6735

Active-Low Reset Output. The MAX6730/MAX6732/MAX6734 provide an open-

drain output. The MAX6731/MAX6733/MAX6735 provide a push-pull output. RST

1

2

1

2

1

2

RST asserts low when any of the following conditions occur: V 1 or V 2 drops below

CC CC

its preset threshold, RSTIN drops below its reset threshold, or MR is driven low.

Open-drain versions require an external pullup resistor.

GND Ground

Active-Low Watchdog Output. The MAX6730/MAX6732/MAX6734 provide an open-

drain WDO output. The MAX6731/MAX6733/MAX6735 provide a push-pull WDO

output. WDO asserts low when no low-to-high or high-to-low transition occurs on

3

4

WDO WDI within the watchdog timeout period (t ) or if an undervoltage lockout

WD

condition exists for V 1, V 2, or RSTIN. WDO deasserts without a timeout period

CC

when V 1, V 2, and RSTIN exceed their reset thresholds, or when the manual

CC

reset input is deasserted. Open-drain versions require an external pullup resistor.

Active-Low Manual Reset Input. Drive MR low to force a reset. RST remains

asserted as long as MR is low and for the reset timeout period after MR releases

4

5

—

5

3

MR

high. MR has a 50kΩ pullup resistor to V 1; leave MR open or connect to V 1 if

CC

unused.

Watchdog Input. If WDI remains high or low for longer than the watchdog timeout

period, the internal watchdog timer expires and the watchdog output asserts low.

The internal watchdog timer clears whenever RST asserts or a rising or falling edge

on WDI is detected. The watchdog has an initial watchdog timeout period (35s min)

after each reset event and a short timeout period (1.12s min) after the first valid

WDI transition. Floating WDI does not disable the watchdog timer function.

5

WDI

Primary Supply Voltage Input. V 1 provides power to the device when it is greater

CC

6

4

8

6

V

1

CC

than V 2. V 1 is the input to the primary reset threshold monitor.

CC

Secondary Supply Voltage Input. V 2 provides power to the device when it is

CC

—

V

2

CC

greater than V 1. V 2 is the input to the secondary reset threshold monitor.

CC

Undervoltage Reset Comparator Input. RSTIN provides a high-impedance

comparator input for the adjustable reset monitor. RST asserts low if the voltage at

—

7

RSTIN RSTIN drops below the 626mV internal reference voltage. Connect a resistive

voltage-divider to RSTIN to monitor voltages higher than 626mV. Connect RSTIN to

V

1 or V 2 if unused.

CC CC

_______________________________________________________________________________________

7

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Table 1. Reset Voltage Threshold Suffix Guide**

Table 2. Reset Timeout Period Suffix Guide

V

1 NOMINAL

VOLTAGE

V

2 NOMINAL

CC

VOLTAGE

ACTIVE TIMEOUT PERIOD

TIMEOUT

CC

PART NO. SUFFIX

PERIOD SUFFIX

MIN (ms)

1.1

MAX (ms)

2.2

THRESHOLD(V)

4.625

4.375

3.075

2.925

2.625

3.075

2.925

2.625

3.075

2.925

2.625

3.075

2.925

2.625

3.075

2.925

2.625

2.313

2.188

2.313

2.188

2.313

2.188

2.313

2.188

1.665

1.575

1.665

1.575

1.665

1.575

THRESHOLD (V)

3.075

2.925

2.625

2.313

2.188

1.665

1.575

1.388

1.313

1.110

1.050

0.833

0.788

1.665

1.575

1.388

1.313

1.110

1.050

0.833

0.788

1.388

1.313

1.110

1.050

0.833

0.788

D1

D2

D3

D5

D6

D4

LT

MS

MR

TZ

SY

RY

TW

SV

RV

TI

SH

RH

TG

SF

RF

TE

SD

RD

ZW

YV

ZI

YH

ZG

YF

ZE

YD

WI

VH

WG

VF

8.8

17.6

140

280

560

1120

2240

1120

Detailed Description

Supply Voltages

The MAX6730–MAX6735 microprocessor (µP) supervi-

sors maintain system integrity by alerting the µP to fault

conditions. The MAX6730–MAX6735 monitor one to

three supply voltages in µP-based systems and assert

an active-low reset output when any monitored supply

voltage drops below its preset threshold. The output

state remains valid for V 1 or V 2 greater than +0.8V.

CC

Threshold Levels

The two-letter code in the Reset Voltage Threshold

Suffix Guide (Table 1) indicates the threshold level

combinations for V 1 and V 2.

CC

Reset Output

The MAX6730–MAX6735 feature an active-low reset out-

put (RST). RST asserts when the voltage at either V 1 or

CC

RSTIN

V

2 falls below the voltage threshold level, V

CC

drops below its threshold, or MR is driven low (Figure 1).

RST remains low for the reset timeout period (Table 2)

after V 1, V 2, and RSTIN increase above their

CC

respective thresholds and after MR releases high.

Whenever V 1, V 2, or RSTIN go below the reset

WE

VD

CC

threshold before the end of the reset timeout period, the

internal timer restarts. The MAX6730/MAX6732/ MAX6734

provide an open-drain RST output, and the MAX6731/

MAX6733/MAX6735 provide a push-pull RST output.

**Standard versions are shown in bold and are available in a

D3 timeout option only. Standard versions require 2500-piece

order increments and are typically held in sample stock. There

is a 10,000-piece order increment on nonstandard versions.

Other threshold voltages may be available; contact factory

for availability.

8

_______________________________________________________________________________________

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Manual Reset Input

Many µP-based products require manual reset capabil-

ity, allowing the operator, a test technician, or external

logic circuitry to initiate a reset. A logic low on MR

V

asserts the reset output, clears the watchdog timer,

EXT_TH

and deasserts the watchdog output. Reset remains

asserted while MR is low and for the reset timeout peri-

R1

R2

MAX6734

MAX6735

RSTIN

od (t ) after MR returns high. An internal 50kΩ pullup

RP

resistor allows MR to be left open if unused. Drive MR

with TTL or CMOS-logic levels or with open-drain/col-

lector outputs. Connect a normally open momentary

switch from MR to GND to create a manual reset func-

tion; external debounce circuitry is not required.

Connect a 0.1µF capacitor from MR to GND to provide

additional noise immunity when driving MR over long

cables or if the device is used in a noisy environment.

GND

Adjustable Input Voltage (RSTIN)

The MAX6734/MAX6735 provide an additional high-

impedance comparator input with a 626mV threshold to

monitor a third supply voltage. To monitor a voltage

higher than 626mV, connect a resistive-divider to the

circuit as shown in Figure 2 to establish an externally

Figure 2. Monitoring a Third Voltage

controlled threshold voltage, V

.

EXT_TH

(R1+ R2)

VEXT_TH = 626mV ×

R2

V

1,

CC

V

TH

V

CC

(MIN)

2

RSTIN

t

RP

RST

WDO

MR

Figure 1. RST, WDO, and MR Timing Diagram

_______________________________________________________________________________________

9

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

The RSTIN comparator derives power from V 1, and

CC

The usual watchdog timeout period (1.12s min) begins

after the initial watchdog timeout period (t ) expires

the input voltage must remain less than or equal to

WD-L

V 1. Low leakage current at RSTIN allows the use of

CC

or after the first transition on WDI (Figure 3). During nor-

mal operating mode, the supervisor asserts the WDO

output if the µP does not update the WDI with a valid

transition (high to low or low to high) within the standard

large-valued resistors, resulting in reduced power con-

sumption of the system.

Watchdog

The watchdog feature monitors µP activity through

the watchdog input (WDI). A rising or falling edge on

timeout period (t ) (1.12s min).

WD-S

Connect MR to WDO to force a system reset in the

event that no rising or falling edge is detected at WDI

within the watchdog timeout period. WDO asserts low

when no edge is detected by WDI, the RST output

asserts low, the watchdog counter immediately clears,

and WDO returns high. The watchdog counter restarts,

using the long watchdog period, when the reset timeout

period ends (Figure 4).

WDI within the watchdog timeout period (t ) indi-

WD

cates normal µP operation. WDO asserts low if WDI

remains high or low for longer than the watchdog

timeout period. Floating WDI does not disable the

watchdog timer.

The MAX6730–MAX6735 include a dual-mode watch-

dog timer to monitor µP activity. The flexible timeout

architecture provides a long-period initial watchdog

mode, allowing complicated systems to complete

lengthy boots, and a short-period normal watchdog

mode, allowing the supervisor to provide quick alerts

when processor activity fails. After each reset event

Ensuring a Valid RESET

Output Down to V

= 0

CC

The MAX6730–MAX6735 guarantee proper operation

down to V = +0.8V. In applications that require valid

CC

reset levels down to V

= 0, use a 100kΩ pulldown

CC

(V

power-up, brownout, or manual reset), there is a

resistor from RST to GND. The resistor value used is not

CC

long initial watchdog period of 35s (min). The long

watchdog period mode provides an extended time for

the system to power up and fully initialize all µP and

system components before assuming responsibility for

routine watchdog updates.

critical, but it must be large enough not to load the

reset output when V

is above the reset threshold. For

CC

most applications, 100kΩ is adequate. Note that this

configuration does not work for the open-drain outputs

of MAX6730/MAX6732/MAX6734.

V

1,

CC

V

TH

V

CC

(MIN)

2

RSTIN

t

RP

RST

WDO

WDI

<t

>t

<t

WD-S

WD-L

WD-S

t

WD-S

Figure 3. Watchdog Input/Output Timing Diagram (MR and WDO Not Connected)

10 ______________________________________________________________________________________

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

V

1,

CC

V

TH

V

CC

(MIN)

2

RSTIN

t

RP

RST

WDO

<t

>t

<t

WD-L

WD-S

WDI

MR

t

MR

Figure 4. Watchdog Input/Output Timing Diagram (MR and WDO Connected)

Applications Information

Interfacing to µPs with Bidirectional

V

2

V

CC

1

CC

Reset Pins

Microprocessors with bidirectional reset pins can inter-

face directly with the open-drain RST output options.

However, conditions might occur in which the push-pull

output versions experience logic contention with the

bidirectional reset pin of the µP. Connect a 10kΩ resis-

tor between RST and the µP’s reset I/O port to prevent

logic contention (Figure 5).

RESET TO

OTHER

V

1

2

CC

SYSTEM

COMPONENTS

MAX6731

MAX6733

MAX6735

10k

Ω

µ

P

RST

RESET

CC

Falling V

Transients

CC

The MAX6730–MAX6735 µP supervisors are relatively

GND

immune to short-duration falling V _ transients (glitch-

CC

es). Small glitches on V _ are ignored by the

CC

MAX6730–MAX6735, preventing undesirable reset

pulses to the µP. The Typical Operating Characteristics

show Maximum Transient Duration vs. Reset Threshold

Figure 5. Interfacing to µPs with Bidirectional Reset I/O

______________________________________________________________________________________ 11

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Overdrive, for which reset pulses are not generated.

Functional Diagram

The graph was produced using falling V _ pulses,

CC

starting above V and ending below the reset thresh-

TH

old by the magnitude indicated (reset threshold over-

drive). The graph shows the maximum pulse width that

V

1

CC

MR

a falling V

transient typically might have without

CC

V

1

CC

causing a reset pulse to be issued. As the amplitude of

the transient increases (i.e., goes further below the

reset threshold), the maximum allowable pulse width

decreases. A 0.1µF bypass capacitor mounted close to

MAX6730–

MAX6735

MR

PULLUP

V

_ provides additional transient immunity.

CC

V

1

V

1

V 2

CC

V

2

CC

V

Watchdog Software Considerations

REF

RESET

TIMEOUT

PERIOD

RESET

OUTPUT

DRIVER

RST

Setting and resetting the watchdog input at different

points in the program rather than “pulsing” the watch-

dog input high-low-high or low-high-low helps the

watchdog timer closely monitor software execution.

This technique avoids a “stuck” loop, in which the

watchdog timer continues to be reset within the loop,

preventing the watchdog from timing out. Figure 6

shows an example flow diagram in which the I/O dri-

ving the watchdog input is set high at the beginning of

the program, set low at the beginning of every subrou-

tine or loop, and then set high again when the program

returns to the beginning. If the program “hangs” in any

subroutine, the I/O continually asserts low (or high),

and the watchdog timer expires, issuing a reset or

interrupt.

V

1

CC

WDO

WDI

WATCHDOG

TIMER

RSTIN

V

1

CC

REF

V

/ 2

REF

GND

START

SET WDI

HIGH

PROGRAM

CODE

SUBROUTINE OR

PROGRAM LOOP

SET WDI LOW

HANG IN

SUBROUTINE

COMPLETED

SUBROUTINE

RETURN

Figure 6. Watchdog Flow Diagram

12 ______________________________________________________________________________________

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Standard Versions

PART

MAX6730UTLD3-T

MAX6730UTSD3-T

MAX6730UTRD3-T

MAX6730UTZD3-T

MAX6730UTVD3-T

MAX6731UTLD3-T

MAX6731UTTD3-T

MAX6731UTSD3-T

MAX6731UTRD3-T

MAX6731UTZD3-T

MAX6731UTVD3-T

MAX6732UTLTD3-T

MAX6732UTSYD3-T

MAX6732UTSVD3-T

MAX6732UTRVD3-T

MAX6732UTSHD3-T

MAX6732UTTGD3-T

MAX6732UTSDD3-T

MAX6732UTZWD3-T

MAX6732UTYHD3-T

MAX6732UTZGD3-T

MAX6732UTYDD3-T

MAX6732UTVHD3-T

MAX6732UTWGD3-T

MAX6732UTVDD3-T

MAX6733UTLTD3-T

MAX6733UTSYD3-T

MAX6733UTSVD3-T

MAX6733UTRVD3-T

MAX6733UTSHD3-T

MAX6733UTTGD3-T

MAX6733UTSDD3-T

MAX6733UTZWD3-T

MAX6733UTYHD3-T

TOP MARK

ABCC

ABPB

ABPA

ABPD

ABPC

ABPE

ABCD

ABPG

ABPF

ABPI

PART

TOP MARK

ABQI

ABQG

ABQE

ABQF

ABQD

AEHN

AEHS

AEHR

AEHO

AEHQ

AEHT

AEHP

AEIA

MAX6733UTZGD3-T

MAX6733UTYDD3-T

MAX6733UTVHD3-T

MAX6733UTWGD3-T

MAX6733UTVDD3-T

MAX6734KALTD3-T

MAX6734KASYD3-T

MAX6734KASVD3-T

MAX6734KARVD3-T

MAX6734KASHD3-T

MAX6734KATGD3-T

MAX6734KASDD3-T

MAX6734KAZWD3-T

MAX6734KAYHD3-T

MAX6734KAZGD3-T

MAX6734KAYDD3-T

MAX6734KAVHD3-T

MAX6734KAWGD3-T

MAX6734KAVDD3-T

MAX6735KALTD3-T

MAX6735KASYD3-T

MAX6735KASVD3-T

MAX6735KARVD3-T

MAX6735KASHD3-T

MAX6735KATGD3-T

MAX6735KASDD3-T

MAX6735KAZWD3-T

MAX6735KAZID3-T

MAX6735KAYHD3-T

MAX6735KAZGD3-T

MAX6735KAYDD3-T

MAX6735KAVHD3-T

MAX6735KAWGD3-T

MAX6735KAVDD3-T

ABPH

ABCE

ABPN

ABPM

ABPJ

AEHY

AEHZ

AEHX

AEHV

AEHW

AEHU

AEIB

ABPL

ABPO

ABPK

ABPV

ABPT

ABPU

ABPS

ABPQ

ABPR

ABPP

ABPW

ABQB

ABQA

ABPX

ABPZ

ABQC

ABPY

ABQJ

ABQH

AEIG

AEIF

AEIC

AEIE

AEIH

AEID

AEIO

AAJZ

AEIM

AEIN

AEIL

AEIJ

AEIK

AEII

Note: Sample stock is generally held on standard versions only. Standard versions have an order increment requirement of 2500

pieces. Nonstandard versions have an order increment requirement of 10,000 pieces. Contact factory for availability of nonstandard

versions.

______________________________________________________________________________________ 13

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Pin Configurations

TOP VIEW

RST

GND

WDI

1

2

3

4

8

7

6

5

V 1

CC

RST

GND

WDO

1

2

3

6

5

4

V

1

RST

GND

WDO

1

2

3

6

5

4

V

1

CC

RSTIN

MAX6730

MAX6731

MAX6732

MAX6733

MAX6734

MAX6735

WDI

MR

WDI

V

2

CC

WDO

MR

V

2

CC

SOT23-6

SOT23-8

Typical Operating Circuit

___________________Chip Information

TRANSISTOR COUNT: 1073

+1.8V

+3.3V

PROCESS: BiCMOS

+0.9V

CORE

V

DD

(MEMORY)

CC

(I/O)

V

2

V 1

CC

RSTIN

MAX6730

RST

WDI

RESET

µ

P

I/O

NMI

WDO

PUSHBUTTON

SWITCH

MR

GND

Selector Guide

VOLTAGE

MONITORS

WATCHDOG

INPUT

WATCHDOG

OUTPUT

PART NUMBER

RST OUTPUT

MANUAL RESET

MAX6730

MAX6731

MAX6732

MAX6733

MAX6734

MAX6735

1

2

3

Open Drain

Push-Pull

√

Open Drain

Push-Pull

Open Drain

Push-Pull

—

√

Open Drain

Push-Pull

Open Drain

Push-Pull

Open Drain

Push-Pull

√

14 ______________________________________________________________________________________

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information

go to www.maxim-ic.com/packages.)

______________________________________________________________________________________ 15

Single-/Dual-/Triple-Voltage µP Supervisory

Circuits with Independent Watchdog Output

Package Information (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information

go to www.maxim-ic.com/packages.)

SEE DETAIL "A"

SYMBOL

MIN

MAX

e

b

A

0.90

0.00

0.90

0.28

0.09

2.80

2.60

1.50

0.30

1.45

0.15

1.30

0.45

0.20

3.00

1.75

0.60

C

L

A1

A2

b

C

D

E

C

L

E1

L

E

E1

L

0.25 BSC.

L2

e

PIN 1

I.D. DOT

(SEE NOTE 6)

0.65 BSC.

1.95 REF.

e1

0

8

e1

D

C

L

L2

A2

A

GAUGE PLANE

A1

SEATING PLANE

C

0

L

NOTE:

1. ALL DIMENSIONS ARE IN MILLIMETERS.

2. FOOT LENGTH MEASURED FROM LEAD TIP TO UPPER RADIUS OF

HEEL OF THE LEAD PARALLEL TO SEATING PLANE C.

DETAIL "A"

3. PACKAGE OUTLINE EXCLUSIVE OF MOLD FLASH & METAL BURR.

4. PACKAGE OUTLINE INCLUSIVE OF SOLDER PLATING.

5. COPLANARITY 4 MILS. MAX.

6. PIN 1 I.D. DOT IS 0.3 MM MIN. LOCATED ABOVE PIN 1.

PROPRIETARY INFORMATION

TITLE:

7. SOLDER THICKNESS MEASURED AT FLAT SECTION OF LEAD

BETWEEN 0.08mm AND 0.15mm FROM LEAD TIP.

8. MEETS JEDEC MO178.

PACKAGE OUTLINE, SOT-23, 8L BODY

APPROVAL

DOCUMENT CONTROL NO.

REV.

1

21-0078

D

1

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

Printed USA

is a registered trademark of Maxim Integrated Products.

型号:	MAX6731UTTD3-T
是否无铅：	含铅
是否Rohs认证：	不符合
生命周期：	Obsolete
零件包装代码：	SOT-23
包装说明：	SOT-23, 6 PIN
针数：	6
Reach Compliance Code：	not_compliant
ECCN代码：	EAR99
HTS代码：	8542.39.00.01
风险等级：	5.1
其他特性：	RESET THRESHOLD VOLTAGE IS 3.075V
可调阈值：	NO
模拟集成电路 - 其他类型：	POWER SUPPLY MANAGEMENT CIRCUIT
JESD-30 代码：	R-PDSO-G6
JESD-609代码：	e0
长度：	2.9 mm
湿度敏感等级：	1
信道数量：	1
功能数量：	1
端子数量：	6
最高工作温度：	85 °C
最低工作温度：	-40 °C
封装主体材料：	PLASTIC/EPOXY
封装代码：	LSSOP
封装等效代码：	TSOP6,.11,37
封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE, LOW PROFILE, SHRINK PITCH
峰值回流温度（摄氏度）：	245
电源：	1/5 V
认证状态：	Not Qualified
座面最大高度：	1.45 mm
子类别：	Power Management Circuits
最大供电电压 (Vsup)：	5.5 V
最小供电电压 (Vsup)：	0.8 V
表面贴装：	YES
技术：	BICMOS
温度等级：	INDUSTRIAL
端子面层：	Tin/Lead (Sn/Pb)
端子形式：	GULL WING
端子节距：	0.95 mm
端子位置：	DUAL
处于峰值回流温度下的最长时间：	NOT SPECIFIED
宽度：	1.625 mm
Base Number Matches：	1

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