MAX6705ATKA+T - Maxim Integrated - Datasheet.Directory

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General Description

The MAX6701–MAX6708 microprocessor (µP) supervisory

circuits reduce the complexity and components required

to monitor power-supply functions in µP systems. These

devices significantly improve system reliability and accu-

racy compared to separate ICs or discrete components.

The MAX6701−MAX6708 family provides four func-

tions: a reset output during power-up, power-down, and

brownout conditions; an independent watchdog output

that goes low if the watchdog input has not been toggled

within 1.6s; a 0.62V threshold detector for power-fail

warning; and an active-low manual reset input.

The MAX6701–MAX6708 family offers several pinout

options to accommodate a variety of multivoltage micro-

processor supervision applications.

The MAX6701(A)/MAX6702(A)/MAX6703(A) monitor

three supply voltages (one fixed threshold and two

adjustable) to drive a single reset output and include a

manual reset input and a watchdog timer with an inde-

pendent output. The MAX6704 monitors a single-supply

voltage to drive complementary reset outputs and

includes an independent adjustable power-fail-in/power-

fail-out comparator, a manual reset input, and a reset-

based watchdog timer. The MAX6705(A)/MAX6706(A)/

MAX6707(A) monitor a single-supply voltage to drive

a single reset output and include an independent

adjustable power-fail-in/power-fail-out comparator, a

manual reset input, and a watchdog timer with an inde-

pendent output. The MAX6708 is the same as the

MAX6704 but without the watchdog timer function.

See the Detailed Description for differences between

non-A and A versions.

Applications

Features

●Small 8-Pin SOT23 Package

●Precision Monitoring of +5.0V, +3.3V, +3.0V, +2.5V

Supply Voltages

●140ms Reset Timeout Delay

●Power-Fail Input with Independent Output; Monitor

Inputs Down to 0.62V (MAX6704−MAX6708)

●Dual Adjustable Reset Input for Triple-Voltage

Monitoring (MAX6701(A)/MAX6702(A)/MAX6703(A))

●1.6s Watchdog Timeout Period

(MAX6701(A)−MAX6707(A))

●Independent Watchdog Output

(MAX6701(A)/MAX6702(A)/MAX6703(A)/

MAX6705(A)/MAX6706(A)/MAX6707(A))

●Manual Reset Input

●Four Reset Output Stage Options

Active Low Push-Pull (MAX6701(A), MAX6705(A))

Active Low Open Drain (MAX6703(A), MAX6707(A))

Active High Push-Pull (MAX6702(A), MAX6706(A))

Dual Active Low/High Push-Pull (MAX6704,

MAX6708)

●Guaranteed Reset Valid to VCC = 1V

●Immune to Short Falling VCC Transients

●Low Cost, Few External Components

Pin Configurations continued at end of data sheet.

Ordering Information continued at end of data sheet.

Insert the desired suffix letter (from the Threshold Suffix Guide

table) into the blank to complete the part number. All devices

must be ordered in increments of 2500 pieces. Sample stock is

typically held on standard versions only. Contact factory for

availability.

Devices are available in both leaded and lead-free packaging.

Specify lead-free by replacing “-T” with “+T” when ordering.

PART TEMP RANGE PIN-PACKAGE

MAX6701_KA-T -40°C to +125°C 8 SOT23

MAX6701A_KA-T -40°C to +125°C 8 SOT23

WDI

RST_IN2RST_IN1

( ) ARE FOR MAX6702(A) ONLY.

WDO

RESET (RESET)VCC

GND

SOT23

TOP VIEW

MAX6701(A)

MAX6702(A)

MAX6703(A)

MAX6701-08/

MAX6701A-03A/

MAX6705A-07A

Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

19-1952; Rev 4; 5/14

Pin Congurations

Ordering Information

Typical Operating Circuit and Selector Guide appear at

end of data sheet.

VCC .......................................................................-0.3V to +6.0V

Open-Drain RESET, WDO, PFO ........................-0.3V to +6.0V

Push-Pull RESET, RESET, WDO, PFO ... -0.3V to (VCC + 0.3V)

MR, WDI, PFI, RST_IN1, RST_IN2 ......... -0.3V to (VCC + 0.3V)

Input Current (VCC) ............................................................20mA

Output Current (O, WDO) ..................................................20mA

Continuous Power Dissipation (TA = +70°C)

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

Operating Temperature Range ......................... -40°C to +125°C

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

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

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

(VCC = +4.25V to +5.5V for L/M versions, VCC = +2.55V to +3.6V for the T/S/R versions, VCC = +2.1V to +2.75V for the Z/Y versions.

TA = -40°C to +125°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Voltage Range VCC

TA = 0°C to +125°C 1.0 5.5 V

TA = -40°C to +125°C 1.2 5.5

Supply Current

MR Unconnected ICC

VCC < 5.5V, no load 12 25

µAVCC < 3.6V, no load 9 20

VCC < 3.6V, no load (MAX6708 only) 6 20

VCC Reset Threshold

(VCC falling) VTH

MAX670_L/MAX670_AL TA = -40°C to +85°C 4.50 4.63 4.75

TA = -40°C to +125°C 4.47 4.78

MAX670_M/MAX670_AM TA = -40°C to +85°C 4.25 4.38 4.50

TA = -40°C to +125°C 4.22 4.53

MAX670_T/MAX670_AT TA = -40°C to +85°C 3.00 3.08 3.15

TA = -40°C to +125°C 2.97 3.17

MAX670_S/MAX670_AS TA = -40°C to +85°C 2.85 2.93 3.00

TA = -40°C to +125°C 2.83 3.02

MAX670_R/MAX670_AR TA = -40°C to +85°C 2.55 2.63 2.70

TA = -40°C to +125°C 2.53 2.72

MAX670_Z/MAX670_AZ TA = -40°C to +85°C 2.25 2.32 2.38

TA = -40°C to +125°C 2.24 2.40

MAX670_Y/MAX670_AY TA = -40°C to +85°C 2.12 2.19 2.25

TA = -40°C to +125°C 2.11 2.27

Reset Threshold

Temperature Coefficient ∆VTH 60 ppm/°C

VCC to Reset Output Delay VCC falling at 10mV/µs 12 µs

Reset Timeout Period tRP

TA = -40°C to +85°C 140 200 280 ms

TA = -40°C to +125°C 120 300

VCC Falling to WDO Delay MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX6705(A)/

MAX6706(A)/MAX6707(A) 5 µs

PFI, RST_IN1, RST_IN2

Threshold VCC = 1.8V to 5.5V TA = -40°C to +85°C 602 618 634 mV

TA = -40°C to +125°C 593 642

PFI Hysteresis 6 mV

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MAX6701-08/

MAX6701A-03A/

MAX6705A-07A

Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Electrical Characteristics

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.

Absolute Maximum Ratings

Note 1: Over-temperature limits are guaranteed by design and not production tested. Devices are tested at TA = +25°C.

Note 2: Guaranteed by design. Not production tested.

(VCC = +4.25V to +5.5V for L/M versions, VCC = +2.55V to +3.6V for the T/S/R versions, VCC = +2.1V to +2.75V for the Z/Y versions.

TA = -40°C to +125°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

PFI, RST_IN1, RST_IN2

Leakage Current (Note 2) TA = -40°C to +85°C -50 +50 nA

TA = -40°C to +125°C -200 +200

PFI to PFO Delay tPF 1 µs

MR Input Voltage VIL 0.3 x VCC V

VIH 0.7 x VCC

MR Minimum Input Pulse 1 µs

MR Glitch Rejection 100 ns

MR to Reset Delay tMD 200 ns

VCC Rising to WDO Delay MAX6701(A)/MAX6702(A)/MAX6703(A)/

MAX6705(A)/MAX6706(A)/MAX6707(A) 100 ns

MR Pullup Resistance 25 50 75 kΩ

Watchdog Timeout Period tWD

TA = -40°C to +85°C 1.12 1.6 2.4 s

TA = -40°C to +125°C 0.96 2.52

WDI Pulse Width tWDI (Note 2) 50 ns

WDI Input Voltage VIL 0.3 x VCC V

VIH 0.7 x VCC

WDI Input Current IWDI VWDI = 0V or VCC -1 +1 µA

RESET, WDO Output Low

(Push-Pull or Open Drain) VOL

VCC ≥ 1.0V, ISINK = 50µA, output asserted

(TA = 0°C to +125°C) 0.3

VVCC ≥ 1.2V, ISINK = 100µA, output asserted 0.3

VCC ≥ 2.55V, ISINK = 1.2mA, output asserted 0.3

VCC ≥ 4.25V, ISINK = 3.2mA, output asserted 0.4

PFO Output Low

(Push-Pull or Open Drain) VOL

VCC ≥ 1.80V, ISINK = 200µA, output asserted 0.3

VVCC ≥ 2.55V, ISINK = 1.2mA, output asserted 0.3

VCC ≥ 4.25V, ISINK = 3.2mA, output asserted 0.4

RESET, WDO, PFO Output

High (Push-Pull Only) VOH

VCC ≥ 2.7V, ISOURCE = 500µA, output not asserted 0.8 x VCC V

VCC ≥ 4.75V, ISOURCE = 800µA, output not asserted 0.8 x VCC

RESET, WDO, PFO

Output Open-Drain

Leakage Current

ILKG VCC > VTH, output not asserted 1.0 µA

RESET Output High

(Push-Pull Only) VOH

VCC ≥ 1.0V, ISOURCE = 1µA, reset asserted

(TA = 0°C to +125°C) 0.8 x VCC

VVCC ≥ 1.2V, ISOURCE = 50µA, reset asserted 0.8 x VCC

VCC ≥ 2.55V, ISOURCE = 500µA, reset asserted 0.8 x VCC

VCC ≥ 4.25V, ISOURCE = 800µA, reset asserted 0.8 x VCC

RESET Output Low

(Push-Pull Only) VOL

VCC ≥ 2.7V, ISINK = 1.2mA, reset not asserted 0.3 V

VCC ≥ 4.75V, ISINK = 3.2mA, reset not asserted 0.4

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MAX6701-08/

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Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Electrical Characteristics (continued)

(TA = +25°C, unless otherwise noted.)

150

100

250

300

200

350

0 800 1200400 1600 2000 2400 2800 3200

VCC - VOH

vs. SOURCE CURRENT

MAX6701 toc08

SOURCE CURRENT (µA)

VCC - VOH (mV)

VCC 4.25V

100

0 800 1600 2400400 1200 2000 2800 3200

OUTPUT-VOLTAGE LOW

vs. SINK CURRENT

MAX6701 toc07

SINK CURRENT (µA)

VOL (mV)

VCC 4.25V

0 40 80 120 160

MAXIMUM VCC TRANSIENT DURATION

vs. RESET THRESHOLD OVERDRIVE

MAX6701 toc06

RESET THRESHOLD OVERDRIVE (mV)

MAXIMUM TRANSIENT DURATION (µs)

MAX670_Y

RESET OCCURS

ABOVE LINE

0.95

0.98

0.97

0.96

0.99

1.00

1.01

1.02

1.03

1.04

1.05

-40 10-15 35 60 85

NORMALIZED RESET THRESHOLD

vs. TEMPERATURE

MAX6701 toc05

TEMPERATURE (°C)

NORMALIZED RESET THRESOLD

1.70

1.65

1.60

1.55

1.50

-40 10-15 35 60 85

WATCHDOG TIMEOUT PERIOD

vs. TEMPERATURE

MAX6701 toc04

TEMPERATURE (°C)

WATCHDOG TIMEOUT PERIOD (s)

-40 10-15 35 60 85

VCC TO RESET OUTPUT DELAY

vs. TEMPERATURE

MAX6701 toc03

TEMPERATURE (°C)

VCC TO RESET OUTPUT DELAY (s)

210

205

200

195

190

-40 10-15 35 60 85

RESET TIMEOUT PERIOD

vs. TEMPERATURE

MAX6701 toc02

TEMPERATURE (°C)

RESET TIMEOUT PERIOD (ms)

-40 10-15 35 60 85

SUPPLY CURRENT

vs. TEMPERATURE

MAX6701 toc01

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

VCC = 5V

VCC = 3.3V

MAX6705(A)

MAX6708

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MAX6701-08/

MAX6701A-03A/

MAX6705A-07A

Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Typical Operating Characteristics

NAME FUNCTION

MAX6701(A)

MAX6702(A)

MAX6703(A)

MAX6704

MAX6705(A)

MAX6706(A)

MAX6707(A)

MAX6708

1 1 1 1 MR

Active-Low, Manual Reset Input, Internal 50kΩ Pullup

to VCC. Pull low to force a reset. Reset remains active

as long as MR is low and the reset timeout period after

MR goes high. Leave unconnected or connect to VCC if

unused. WDO deasserts when MR is low (MAX6701(A)/

MAX6702(A)/MAX6703(A)/ MAX6705(A)/ MAX6706(A)/

MAX6707(A) only)

2 2 2 2 VCC

Supply Voltage for MAX6701–MAX6708 and Input for

Primary Reset Threshold Monitor. Push-pull outputs are

3 3 3 3 GND Ground

— 4 4 4 PFI

Power-Fail Voltage Monitor Input. High-impedance

input for internal power-fail comparator. Connect this

pin to an external resistive-divider network to set the

reset threshold voltage; 0.62V (typ) threshold. Connect

to GND or VCC when not used.

— 5 5 5 PFO Power-Fail Monitor Output. Open drain or push-pull

active low. PFO goes low when PFI is less than 0.62V.

6 6 6 — WDI

Watchdog Input. If WDI remains high or low for longer

than the watchdog timeout period, the internal watchdog

timer runs out and WDO is asserted. WDO is asserted

low after each watchdog overflow and remains low until

the watchdog timer is cleared (the reset output is not

affected). The internal watchdog timer clears whenever

a VCC/RST_IN1/RST_IN2 reset is asserted, the manual

reset is asserted, or WDI sees a rising or falling edge.

The watchdog timer remains cleared until the reset output

is deasserted. On the MAX6704, RESET pulse asserts

for the reset timeout period after each watchdog timeout

overflow. The watchdog timer cannot be disabled.

— — — 6 N.C. No Connection. Not internally connected.

7 7 7 7 RESET

Active-Low Reset Output (Open Drain or Push-Pull).

RESET changes from high to low when the VCC input

drops below the selected reset threshold (or RST_IN1/

RST_IN2 for the MAX6701(A)/MAX6702(A)/MAX6703(A),

MR is pulled low, or the watchdog triggers a reset

(MAX6704 only). RESET remains low for the reset timeout

period after the reset conditions are terminated.

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MAX6701-08/

MAX6701A-03A/

MAX6705A-07A

Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Pin Description

*RESET active-high for the MAX6702(A)/MAX6706(A).

Detailed Description

Figures 1, 2, and 3 are functional diagrams for the

MAX6705(A)/MAX6706(A)/MAX6707(A), MAX6704/

MAX6708, and MAX6701(A)/MAX6702(A)/MAX6703(A),

respectively.

Reset Output

A microprocessor’s (µP’s) reset input starts the µP in a

known state. The MAX6701–MAX6708 assert reset

during power-up and prevent code execution errors

during power-down or brownout conditions.

On power-up, once VCC reaches 1V, RESET is a

guaranteed logic-low of 0.4V or less. As VCC rises,

RESET stays low. After VCC, RST_IN1, or RST_IN2 rise

above the reset threshold, an internal timer holds RESET

low for about 200ms. RESET pulses low whenever

VCC dips below the reset threshold, including brownout

conditions. If a brownout occurs in the middle of a

previously initiated reset pulse, the pulse continues for

at least another 140ms. On power-down, once VCC

falls below the reset threshold, RESET stays low and is

guaranteed to be 0.4V or less, until VCC drops below 1V.

The MAX6702(A)/MAX6704/MAX6706(A)/MAX6708

active-high RESET output is the complement of the

RESET output, and is guaranteed to be valid with VCC

down to 1V.

NAME FUNCTION

MAX6701(A)

MAX6702(A)

MAX6703(A)

MAX6704

MAX6705(A)

MAX6706(A)

MAX6707(A)

MAX6708

8 — 8 — WDO

Active-Low Watchdog Output (Open Drain or Push-

Pull). WDO is asserted whenever the watchdog

times out and VCC or the reset inputs are below their

respective thresholds. WDO deasserts after a valid

WDI transition without a reset timeout period. In the A

versions, WDO deasserts without a timeout delay when

VCC, RST_IN1, and RST_IN2 rises above its threshold.

Pull MR low to assert WDO (MAX6701/MAX6702/

MAX6703/MAX6705/MAX6706/MAX6707 only). Pull

MR low to deassert WDO (MAX6701(A)/MAX6702(A) /

MAX6703(A)/ MAX6705(A)/MAX6706(A)MAX6707(A)

only)

7* 8 7* 8 RESET

Active-High Reset Output (Push-Pull). RESET changes

from low to high when the VCC input drops below the

selected reset threshold (or RST_IN1/RST_IN2 for

MAX6701(A)/MAX6702(A)/ MAX6703(A), MR is pulled

low, or the watchdog triggers a reset (MAX6704 only).

RESET remains high for the reset timeout period after

the reset conditions are terminated.

4 — — — RST_IN1

Input for User-Adjustable VCC2 Monitor. High-

impedance input for second internal reset comparator.

Connect this pin to an external resistive-divider network

to set the reset threshold voltage; 0.62V (typ) threshold.

Connect to VCC when not used. Reset is asserted

when either VCC, RST_IN1, or RST_IN2 are below

threshold.

5 — — — RST_IN2

Input for User-Adjustable VCC3 Monitor. High-

impedance input for third internal reset comparator.

Connect this pin to an external resistive-divider network

to set the reset threshold voltage; 0.62V (typ) threshold.

Connect to VCC when not used. Reset is asserted

when either VCC, RST_IN1, or RST_IN2 are below

threshold.

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Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Pin Description (continued)

Figure 4. MAX6705/MAX6706/MAX6707 RESET, MR, WDO,

and WDI Timing

Figure 3. MAX6701(A)/MAX6702(A)/MAX6703(A) Functional

Diagram

Figure 2. MAX6704/MAX6708 Functional Diagram

Figure 1. MAX6705(A)/MAX6706(A)/MAX6707(A) Functional

Diagram

tRP tRP

VCC

RESET

WDO

VCC

WDI

VCC

MR EXTERNALLY DRIVEN LOW

VCC

VTH VTH

tMD

NOTE: THE MAX6706 RESET OUTPUT IS THE INVERSE OF THE RESET SHOWN.

RESET

GENERATOR

WATCHDOG

TIMER

RESET (RESET)

WDO

WDI

0.62V 0.62V

VREF

VCC

RST_IN1 RST_IN2

VCC

50kΩ

MAX6701(A)

MAX6702(A)

MAX6703(A)

( ) ARE FOR MAX6702(A) ONLY.

WATCHDOG

TIMER

RESET

GENERATOR

WDI

(MAX6704 ONLY)

RESET

5PFO

0.62V

VREF

VCC

50kΩ

VCC

PFI

MAX6704

MAX6708

GND

WATCHDOG

TIMER

RESET

GENERATOR

VCC

50kΩ

8WDO

7RESET

(RESET)

5PFO

GND

0.62V

( ) ARE FOR MAX6706(A) ONLY.

WDI

VREF

PFI

MAX6705(A)

MAX6706(A)

MAX6707(A)

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Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Standard- vs. A-Version Comparison

The MAX6701/MAX6702/MAX6703/MAX6705/MAX6706/

MAX6707s’ WDO latches low when one of the following

events occurs:

●The watchdog timer times out (1.6s, typ).

●VCC, RST_IN1, or RST_IN2 is below its reset

threshold.

●MR is pulled low.

●WDO only deasserts with a valid WDI transition.

The MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX6705(A)/

MAX6706(A)/ MAX6707(A)s’ WDO asserts when either

VCC, RST_IN1, or RST_IN2 is below its reset thresh-

old. WDO deasserts without a timeout delay when the

undervoltage situation has expired. WDO is latched low

when the watchdog timer elapses without seeing a WDI

transition. WDO deasserts with a valid WDI transition

OR by pulling MR low.

See Figures 4 and 5 for standard-version timing. See

Figures 6 and 7 for A-version timing.

Watchdog Timer

The MAX6701–MAX6707 watchdog circuit monitors the

µP’s activity. If the µP does not toggle the WDI within 1.6s,

WDO goes low. When RESET is asserted, the watchdog

timer stays cleared and does not count. As soon as reset

is released, the timer starts counting. WDO deasserts

after a valid transition is detected at WDI. Pulses as short

as 50ns can be detected.

Typically, WDO is connected to the NMI input of a µP.

When VCC, RST_IN1, or RST_IN2 drop below the reset

threshold, WDO goes low whether or not the watchdog

timer has timed out. Normally this would trigger an NMI,

but RESET goes low simultaneously, and thus overrides

the NMI.

The MAX6704 watchdog circuit does not have an inde-

pendent watchdog output (WDO). If the µP does not

toggle the watchdog input within 1.6s, the MAX6704

asserts a reset output pulse for the reset timeout period.

Manual Reset

The manual reset input (MR) allows reset to be

triggered by a pushbutton switch. The switch is

effectively debounced by the reset pulse width. MR is

CMOS logic compatible, so it can be driven by an external

logic line. MR can be used to force a watchdog timeout to

generate a reset pulse in the MAX6701(A)/MAX6702(A)/

MAX6703(A)/MAX6705(A)/MAX6706(A)/MAX6707(A) by

connecting WDO to MR.

Power-Fail Comparator

The uncommitted power-fail comparator can be used

for various purposes because its noninverting input and

output are externally available. The inverting input is

internally connected to a 0.62V reference. To build an

early warning circuit for power failure, connect the PFI

pin to a voltage-divider (see the Typical Operating

Circuit). Choose the voltage-divider ratio so that the

voltage at PFI falls below 0.62V just before the regulator

drops out. Use PFO to interrupt the µP so it can prepare

for an orderly power-down. The low-input current at this

pin allows for large resistor values in the divider.

Figure 6. MAX6701(A)/MAX6702(A)/MAX6703(A)/

MAX6705(A)/ MAX6706(A)/MAX6707(A) RESET, MR, and

WDO Timing with WDI Three-Stated

Figure 5. MAX6701/MAX6702/MAX6703/MAX6705/MAX6706/

MAX6707 Watchdog

tRP tRP

+5V

RESET

WDO

+5V

tMR

+5V

VCC

VTH VTH

tMD

tWD tWD

+5V

WDI

+5V

WDO

+5V

RESET

+5V

(RESET)

tRP

RESET EXTERNALLY

TRIGGERED BY MR

+5V

( ) ARE FOR MAX6702/MAX6706 ONLY.

tWDI

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Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Reset Input

The MAX6701(A)/MAX6702(A)/MAX6703(A) include two

adjustable reset inputs for monitoring up to a total of

three system voltages (including VCC). The thresholds

for the monitored RST_IN supplies are externally set

with resistor-divider networks (Figure 8). The reset

output is asserted if any of the monitored supplies (VCC,

RST_IN1, or RST_IN2) go below its specified threshold

and remains asserted for the reset timeout period after

all supplies are above their thresholds.

Applications Information

Ensuring a Valid RESET Output

Down to VCC = 0

When VCC falls below 1V, the MAX6701–MAX6708

RESET output no longer sinks current; it becomes an

open circuit. High-impedance CMOS logic inputs can

drift to undetermined voltages if left undriven. If a pull-

down resistor is added to the RESET pin, as shown

in Figure 9, any stray charge or leakage currents are

drained to ground, holding RESET low. A resistor value

(R1) is not critical; 100kΩ is large enough not to load

RESET and small enough to pull RESET to ground.

This application works for push-pull output only (not for

open-drain resets).

Monitoring Other System Voltages

Other systems can be monitored by connecting a

voltage-divider to PFI and adjusting the ratio appropriately.

In noisy systems, a capacitor between PFI and GND

reduces the power-fail circuit’s sensitivity to high-

frequency noise on the line being monitored. Reset can

be asserted on other voltages in addition to the VCC

supply line. Connect PFO to MR to initiate a reset out-

put pulse when PFI drops below 0.62V. Figure 10

shows the MAX6704–MAX6708 configured to assert a

reset output when the secondary supply falls below the

reset threshold.

Generating a Reset from Watchdog Overow

Connect WDO to MR to force a watchdog timeout to gen-

erate a reset pulse for only the reset timeout period on the

MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX6705(A)/

MAX6706(A)/MAX6707(A). When the MAX6704 watch-

dog times out, reset outputs are automatically asserted

(no external connections required). For the MAX6701/

MAX6702/MAX6703/MAX6705/MAX6706/MAX6707 non-A

versions, do not connect WDO to MR; this creates a

locked condition.

Figure 8. Calculating Adjustable Voltage ThresholdsFigure 7. MAX6701(A)/MAX6702(A)/MAX6703(A)/

MAX6705(A)/ MAX6706(A)/MAX6707(A) Watchdog Timing

0.62V

PFI, RST_IN1, OR RST_IN2

VEXTERNAL

0.62

R1 = R2 x (VEXT-TH - 1)

VEXT-TH = (1 + R1) x 0.62V

WHERE VEXT-TH IS THE EXTERNAL VOLTAGE TRIP LEVEL.

MAX6701(A)–

MAX6708

tWD

+5V

WDI

+5V

WDO

+5V

RESET

+5V

(RESET)

tRP

+5V

( ) ARE FOR MAX6702(A)/MAX6706(A) ONLY.

tWDI

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Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Figure 10. Monitoring Other System VoltagesFigure 9. RESET Valid to Ground Circuit

Bold indicates standard version.

PP = push-pull, OD = open drain.

*WDO deasserts when MR is pulled low. See the Standard- vs. A-Version Comparison section for the differences on WDO.

SUFFIX RESET

THRESHOLD (V)

L4.63

M 4.38

T 3.08

S2.93

R2.63

Z2.32

Y 2.19

PART RESET

PP LOW

RESET

PP HIGH

RESET

OD-LOW WDI WDO PFI,

PFO

RST_IN1,

RST_IN2

MAX6701 ✔— — ✔ ✔ PP —✔

MAX6701A* ✔— — ✔ ✔ PP —✔

MAX6702 — ✔—✔ ✔ PP —✔

MAX6702A* — ✔—✔ ✔ PP —✔

MAX6703 — — ✔ ✔ ✔ OD —✔

MAX6703A* — — ✔ ✔ ✔ OD —✔

MAX6704 ✔✔—✔—✔ PP —

MAX6705 ✔— — ✔ ✔ PP ✔ PP —

MAX6705A* ✔— — ✔ ✔ PP ✔ PP —

MAX6706 — ✔—✔ ✔ PP ✔ PP —

MAX6706A* — ✔—✔ ✔ PP ✔ PP —

MAX6707 — — ✔ ✔ ✔ OD ✔ OD —

MAX6707A* — — ✔ ✔ ✔ OD ✔ OD —

MAX6708 ✔✔———✔ PP —

VCC

PFI

PFO

RESET

0.9V

3.3V

MAX6704–

MAX6708

I/O

SUPPLY

CORE

SUPPLY

µP

RESET

(RESET)

() ARE FOR MAX6704/MAX6706(A)/MAX6708 ONLY.

R1 (100kΩ)

RESET

MAX6701(A)

MAX6704

MAX6705(A)

MAX6708

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MAX6701-08/

MAX6701A-03A/

MAX6705A-07A

Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Threshold Sufx Guide

Selector Guide

Insert the desired suffix letter (from the Threshold Suffix Guide

table) into the blank to complete the part number. All devices

must be ordered in increments of 2500 pieces. Sample stock is

typically held on standard versions only. Contact factory for

availability.

Devices are available in both leaded and lead(Pb)-free

packaging. Specify lead-free by replacing “-T” with “+T” when

ordering.

T = Tape and reel.

PART TEMP RANGE PIN-PACKAGE

MAX6702_ KA-T -40°C to +125°C 8 SOT23

MAX6702A_ KA-T -40°C to +125°C 8 SOT23

MAX6703_ KA-T -40°C to +125°C 8 SOT23

MAX6703A_ KA-T -40°C to +125°C 8 SOT23

MAX6704_KA-T -40°C to +125°C 8 SOT23

MAX6705_KA-T -40°C to +125°C 8 SOT23

MAX6705A_KA-T -40°C to +125°C 8 SOT23

MAX6706_KA-T -40°C to +125°C 8 SOT23

MAX6706A_KA-T -40°C to +125°C 8 SOT23

MAX6707_KA-T -40°C to +125°C 8 SOT23

MAX6707A_KA-T -40°C to +125°C 8 SOT23

MAX6708_KA-T -40°C to +125°C 8 SOT23

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

8 SOT23 K8+2 21-0078 90-0176

VCC

PFI

MR PFO

WDO

RESET

UNREGULATED DC

MAX6705(A)

MAX6706(A)

MAX6707(A)

PUSHBUTTON

SWITCH

INTERRUPT

µP

REGULATOR

VCC

RESET

NMI

DC-DC

WDI I/O

( ) ARE FOR MAX6706(A) ONLY.

WDI

PFOPFI

RESET

RESETVCC

GND

SOT23

MAX6704

WDI

PFOPFI

WDO

RESET (RESET)VCC

GND

SOT23

MAX6705(A)

MAX6706(A)

MAX6707(A) N.C.

PFOPFI

RESET

RESETVCC

GND

SOT23

MAX6708

TOP VIEW

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MAX6701-08/

MAX6701A-03A/

MAX6705A-07A

Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Chip Information

TRANSISTOR COUNT: 716

PROCESS: BiCMOS

Ordering Information (continued)Typical Operating Circuit

Pin Congurations (continued)

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.

REVISION

NUMBER

REVISION

DATE DESCRIPTION PAGES

CHANGED

4 5/14 No /V OPNs; removed Automotive reference from Applications section 1

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

are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)

shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.

│

MAX6701-08/

MAX6701A-03A/

MAX6705A-07A

Low-Voltage, SOT23 µP Supervisors with Power-Fail

In/Out, Manual Reset, and Watchdog Timer

Revision History

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.

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MAX6701ALKA+T MAX6701AMKA+T MAX6701ARKA+T MAX6701ASKA+T MAX6701ATKA+T MAX6701AYKA+T

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MAX6703ARKA+T MAX6703ASKA+T MAX6703ATKA+T MAX6703AYKA+T MAX6703AZKA+T MAX6703LKA+T

MAX6703MKA+T MAX6703RKA+T MAX6703SKA+T MAX6703TKA+T MAX6703YKA+T MAX6703ZKA+T

MAX6704LKA+T MAX6704MKA+T MAX6704RKA+T MAX6704SKA+T MAX6704TKA+T MAX6704YKA+T

MAX6704ZKA+T MAX6705ALKA+T MAX6705AMKA+T MAX6705ARKA+T MAX6705ASKA+T MAX6705ATKA+T

MAX6705AYKA+T MAX6705AZKA+T MAX6705LKA+T MAX6705MKA+T MAX6705RKA+T MAX6705SKA+T

MAX6705TKA+T MAX6705YKA+T MAX6705ZKA+T MAX6706ALKA+T MAX6706AMKA+T MAX6706ARKA+T

MAX6706ASKA+T MAX6706ATKA+T MAX6706AYKA+T MAX6706AZKA+T MAX6706LKA+T MAX6706MKA+T

MAX6706RKA+T MAX6706SKA+T MAX6706TKA+T MAX6706YKA+T MAX6706ZKA+T MAX6707ALKA+T

MAX6707AMKA+T MAX6707ARKA+T MAX6707ASKA+T MAX6707ATKA+T MAX6707AYKA+T MAX6707AZKA+T

MAX6707LKA+T MAX6707MKA+T MAX6707RKA+T MAX6707SKA+T MAX6707TKA+T MAX6707YKA+T

MAX6707ZKA+T MAX6708LKA+T MAX6708MKA+T MAX6708RKA+T MAX6708SKA+T MAX6708TKA+T

MAX6708ZKA+T MAX6703TKA+TG071 MAX6705ASKA+ MAX6705RKA+