Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Reset/power-on reset SOT 23 8

General Description

The MAX6746–MAX6753 low-power microprocessor (μP)

supervisory circuits monitor single/dual system supply

voltages from 1.575V to 5V and provide maximum adjust-

ability for reset and watchdog functions. These devices

assert a reset signal whenever the V

supply voltage or

RESET IN falls below its reset threshold or when manual

reset is pulled low. The reset output remains asserted for

the reset timeout period after V

and RESET IN rise

above the reset threshold. The reset function features

immunity to power-supply transients.

The MAX6746–MAX6753 have ±2% factory-trimmed

reset threshold voltages in approximately 100mV

increments from 1.575V to 5.0V and/or adjustable reset

threshold voltages using external resistors.

The reset and watchdog delays are adjustable with

external capacitors. The MAX6746–MAX6751 contain

a watchdog select input that extends the watchdog

timeout period by 128x. The MAX6752/MAX6753 contain

a window watchdog timer that looks for activity outside an

expected window of operation.

The MAX6746–MAX6753 are available with a push-pull

or open-drain active-low RESET output. The MAX6746–

MAX6753 are available in an 8-pin SOT23 package and

are fully specified over the automotive temperature range

(-40°C to +125°C).

Applications

● Medical Equipment

● Automotive

● Intelligent Instruments

● Portable Equipment

● Battery-Powered Computers/Controllers

● Embedded Controllers

● Critical μP Monitoring

● Set-Top Boxes

● Computers

Features

● Factory-Set Reset Threshold Options from 1.575V to

5V in ~100mV Increments

● Adjustable Reset Threshold Options

● Single/Dual Voltage Monitoring

● Capacitor-Adjustable Reset Timeout

● Capacitor-Adjustable Watchdog Timeout

● Min/Max (Windowed) Watchdog Option

● Manual-Reset Input Option

● Guaranteed RESET Valid for V

≥ 1V

● 3.7μA Supply Current

● Push-Pull or Open-Drain RESET Output Options

● Power-Supply Transient Immunity

● Small 8-Pin SOT23 Packages

Selector Guide appears at end of data sheet.

Typical Operating Circuit appears at end of data sheet.

Pin Configurations continued at end of data sheet.

19-2530; Rev 9; 5/14

Note: “_ _” represents the two number suffix needed when

ordering the reset threshold voltage value for the MAX6746/

MAX6747 and MAX6750–MAX6753. The reset threshold volt-

ages are available in approximately 100mV increments. Table

2 contains the suffix and reset factory-trimmed voltages. All

devices are available in tape-and-reel only. There is a 2500-

piece minimum order increment for standard versions (see

Table 3). Sample stock is typically held on standard versions

only. Nonstandard versions require a minimum order increment

of 10,000 pieces. Contact factory for availability.

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

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

+Denotes a lead(Pb)-free/RoHS-compliant package.

T = Tape and reel.

/V denotes an automotive qualified part.

*Future product—contact factory for availability.

PART TEMP RANGE PIN-PACKAGE

MAX6746KA_ _-T -40°C to +125°C 8 SOT23

MAX6746KA_ _/V+T -40°C to +125°C 8 SOT23

MAX6747KA_ _-T -40°C to +125°C 8 SOT23

MAX6747KA_ _/V+T -40°C to +125°C 8 SOT23

MAX6748KA-T -40°C to +125°C 8 SOT23

MAX6749KA-T -40°C to +125°C 8 SOT23

MAX6750KA_ _-T -40°C to +125°C 8 SOT23

MAX6750KA_ __/V+T -40°C to +125°C 8 SOT23

MAX6751KA_ _-T -40°C to +125°C 8 SOT23

MAX6751KA_ _/V+T* -40°C to +125°C 8 SOT23

MAX6752KA_ _-T -40°C to +125°C 8 SOT23

MAX6753KA_ _-T -40°C to +125°C 8 SOT23

MAX6753KA_ _/V+T -40°C to +125°C 8 SOT23

WDI

WDSGND

RESETSWT

SRT

RESET IN (MR)

( ) ARE FOR MAX6746 AND MAX6747 ONLY.

TOP VIEW

MAX6746–

MAX6751

SOT23

MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable

Reset/Watchdog Timeout Delay

Pin Congurations

Ordering Information

Summary of content (14 pages)

PAGE 1
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay General Description The MAX6746–MAX6753 low-power microprocessor (μP) supervisory circuits monitor single/dual system supply voltages from 1.575V to 5V and provide maximum adjustability for reset and watchdog functions. These devices assert a reset signal whenever the VCC supply voltage or RESET IN falls below its reset threshold or when manual reset is pulled low.
PAGE 2
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Absolute Maximum Ratings VCC to GND...........................................................-0.3V to +6.0V SRT, SWT, SET0, SET1, RESET IN, WDS, MR, WDI, to GND......................................…-0.3V to (VCC + 0.3V) RESET (Push-Pull) to GND....................…-0.3V to (VCC + 0.3V) RESET (Open Drain) to GND.............................…-0.3V to +6.0V Input Current (All Pins)......................................
PAGE 3
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Electrical Characteristics (continued) (VCC = +1.2V to +5.5V, TA = TMIN to TMAX, unless otherwise specified. Typical values are at VCC = +5V and TA = +25°C.) (Note 1) PARAMETER Fast Watchdog Timeout Period, SET Ratio = 64, (MAX6752/MAX6753) SYMBOL tWD1 CONDITIONS CSWT = 1500pF MIN TYP MAX 11.38 15.18 18.98 CSWT = 100pF 1.
PAGE 4
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Typical Operating Characteristics (VCC = +5V, TA = +25°C, unless otherwise noted.) 1 1000 10,000 1000 100 NORMAL MODE 10 1 0.1 100,000 100 1000 CSRT = 100pF 1.05 CSRT = 1500pF 0.95 0 25 50 75 100 SUPPLY CURRENT (µA) MAX6746 toc05 MAX6746 toc03 150 125 RESET OCCURS ABOVE THE CURVE 100 75 50 25 -25 0 25 50 75 100 0 125 VTH = 2.92V 0 200 400 600 800 SUPPLY CURRENT vs.
PAGE 5
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) TIMEOUT PERIOD (ms) 26.2 25.8 0.56 0.52 0.48 0.44 25.4 -50 -25 0 25 50 75 100 125 0.40 9.0 RESET AND WATCHING TIMEOUT PERIOD vs. SUPPLY VOLTAGE MAX6746 toc11 CSWT = CSRT = 100pF CSWT = CSRT = 1500pF 8.5 TIMEOUT PERIOD (ms) VCC FALLING AT 1mV/µs 26.6 25.0 0.60 MAX6746 toc09 VCC TO RESET DELAY (µs) 27.
PAGE 6
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Pin Description (continued) PIN MAX6746 MAX6747 MAX6748– MAX6751 MAX6752 MAX6753 NAME FUNCTION 5 5 — WDS Watchdog Select Input. WDS selects the watchdog mode. Connect WDS to ground to select normal mode and the watchdog timeout period. Connect WDS to VCC to select extended mode, multiplying the basic timeout period by a factor of 128. A change in the state of WDS clears the watchdog timer.
PAGE 7
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay tWD1 (MIN) tWD1 (MAX) GUARANTEED TO ASSERT RESET tWD2 (MIN) tWD2 (MAX) GUARANTEED TO GUARANTEED TO NOT ASSERT ASSERT RESET RESET *UNDETERMINED *UNDETERMINED WDI CONDITION 1 FAST FAULT WDI CONDITION 2 NORMAL OPERATION WDI CONDITION 3 SLOW FAULT *UNDETERMINED STATES MAY OR MAY NOT GENERATE A FAULT CONDITION Figure 1.
PAGE 8
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay configured to monitor VCC voltage by connecting VCC to VMON_TH. VMON_TH Dual-Voltage Monitoring (MAX6750/MAX6751) R1 VCC RESET IN R2 GND VCC MAX6748 MAX6749 MAX6750 MAX6751 The MAX6750 and MAX6751 contain both factory-trimmed threshold voltages and an adjustable reset threshold input, allowing the monitoring of two voltages, VCC and VMON_ TH (see Figure 2).
PAGE 9
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay VCC tRP tWD x 128 WDI OV VCC RESET OV EXTENDED MODE (WDS = VCC) Figure 4b. Watchdog Timing Diagram, WDS = VCC Watchdog Timer MAX6746–MAX6751 The watchdog’s circuit monitors the μP’s activity. It the μP does not toggle the watchdog input (WDI) within tWD (user-selected), RESET asserts for the reset timeout period.
PAGE 10
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay tWDI < tWD1 (MIN) 5V 3.3V VCC WDI MAX6747 MAX6749 MAX6451 MAX6753 RESET (a) FAST FAULT tWDI > tWD2 (MAX) RESET 100kΩ VCC µP RESET N GND GND WDI RESET Figure 6. Interfacing to Other Voltage Levels (b) SLOW FAULT tWD1 (MAX) < tWDI < tWD2 (MIN) WDI RESET (c) NORMAL OPERATION (NO PULSING, OUTPUT STAYS HIGH) Figure 5.
PAGE 11
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay ending below it by the magnitude indicated (reset threshold overdrive). As the magnitude of the transient increases (farther below the reset threshold), the maximum allowable pulse width decreases. Typically, a VCC transient that goes 100mV below the reset threshold and lasts 50μs or less does not cause a reset pulse to be issued.
PAGE 12
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Table 2. Reset Threshold Voltage Suffix (TA = -40°C to +125°C) Table 3. Standard Version Table PART TOP MARK SUFFIX MIN TYP MAX MAX6746KA16 AEDI 50 4.900 5.000 5.100 MAX6746KA23 AEDJ 49 4.802 4.900 4.998 MAX6746KA26 AEDK 48 4.704 4.800 4.896 MAX6746KA29 AALN 47 4.606 4.700 4.794 MAX6746KA46 AEDL 46 4.533 4.625 4.718 MAX6747KA16 AALO 45 4.410 4.500 4.
PAGE 13
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Selector Guide PART FIXED VCC RESET THRESHOLD ADJUSTABLE RESET THRESHOLD STANDARD WATCHDOG TIMER MIN/MAX WATCHDOG TIMER PUSH/ PULL RESET OPEN-DRAIN RESET MANUALRESET INPUT MAX6746 X — X MAX6747 X — X — X — X — — X X MAX6748 — X X MAX6749 — X X — X — — — — X — MAX6750 X X X — X — — MAX6751 X MAX6752 X X X — — X — — — X X — — MAX6753 X — — X — X — T
PAGE 14
MAX6746–MAX6753 μP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 7/02 Initial release — 3 12/05 Added the lead-free notation 1 4 9/10 Added the automotive version of the MAX6746 and the MAX6753 and revised the Typical Operating Characteristics 5 12/10 Added the automotive version of the MAX6750 1 6 4/11 Added the automotive version of the MAX6747 1 7 12/13 Added the automotive version of the MAX6