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General Description

The MAX691A/MAX693A/MAX800L/MAX800M micro-

processor (µP) supervisory circuits are pin-compatible

upgrades to the MAX691, MAX693, and MAX695. They

improve performance with 30µA supply current, 200ms

typ reset active delay on power-up, and 6ns chip-

enable propagation delay. Features include write pro-

tection of CMOS RAM or EEPROM, separate watchdog

outputs, backup-battery switchover, and a RESET out-

put that is valid with V

down to 1V. The MAX691A/

MAX800L have a 4.65V typical reset-threshold voltage,

and the MAX693A/MAX800Ms’ reset threshold is 4.4V

typical. The MAX800L/MAX800M guarantee power-fail

accuracies to ±2%.

________________________Applications

Computers

Controllers

Intelligent Instruments

Automotive Systems

Critical µP Power Monitoring

____________________________Features

♦ 200ms Power-OK/Reset Timeout Period

♦ 1µA Standby Current, 30µA Operating Current

♦ On-Board Gating of Chip-Enable Signals,

10ns max Delay

♦ MaxCap

™

or SuperCap

™

Compatible

♦ Guaranteed

RREESSEETT

Assertion to V

= +1V

♦ Voltage Monitor for Power-Fail or Low-Battery

Warning

♦ Power-Fail Accuracy Guaranteed to ±2%

(MAX800L/M)

♦ Available in 16-Pin Narrow SO, Plastic

DIP, and TSSOP Packages

MAX691A/MAX693A/MAX800L/MAX800M

Microprocessor Supervisory Circuits

________________________________________________________________ Maxim Integrated Products 1

RESET

WDO

CE IN

GND

OUT

VBATT

TOP VIEW

MAX691A

MAX693A

MAX800L

MAX800M

CE OUT

WDI

PFO

PFI

OSC SEL

OSC IN

LOW LINE

BATT ON

DIP/SO/TSSOP

Pin Configuration

MAX691A

MAX693A

MAX800L

MAX800M

OUT

BATT ON

CE OUT

CE IN

WDI

PFO

RESET

VBATT

PFI

GND

OSC IN

OSC SEL

ADDRESS

DECODE

AUDIBLE

ALARM

REGULATOR

+8V

0.1µF

CMOS RAM

A0-A15

I/O

NMI

RESET

µP

LOW LINE WDO

SYSTEM STATUS INDICATORS

CONNECTION

0.47F*

1N4148

*MaxCap

614

Typical Operating Circuit

19-0094; Rev 10; 11/05

PART

MAX691ACUE

MAX691ACPE 0°C to +70°C

0°C to +70°C

TEMP RANGE PIN-PACKAGE

16 TSSOP

16 Plastic DIP

MAX691AC/D

MAX691AEJE -40°C to +85°C

0°C to +70°C Dice*

16 CERDIP

MAX691AEUE

MAX691AESE -40°C to +85°C

0°C to +70°C 16 TSSOP

16 Narrow SO

MAX691AEPE -40°C to +85°C 16 Plastic DIP

MAX691AMJE -55°C to +125°C 16 CERDIP

SuperCap is a registered trademark of Baknor Industries. MaxCap is a registered trademark of The Carborundum Corp.

MAX691ACSE 0°C to +70°C 16 Narrow SO

Ordering Information continued on last page.

*Dice are specified at T

= +25°C, DC parameters only.

Devices in PDIP, SO and TSSOP packages are available in both

leaded and lead-free packaging. Specify lead free by adding

the + symbol at the end of the part number when ordering.

Lead free not available for CERDIP package.

MAX691ACWE 0°C to +70°C 16 Wide SO

MAX691AEWE -40°C to +85°C 16 Wide SO

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.

Ordering Information

Summary of content (19 pages)

PAGE 1
9-0094; Rev 10; 11/05 Microprocessor Supervisory Circuits The MAX691A/MAX693A/MAX800L/MAX800M microprocessor (µP) supervisory circuits are pin-compatible upgrades to the MAX691, MAX693, and MAX695. They improve performance with 30µA supply current, 200ms typ reset active delay on power-up, and 6ns chipenable propagation delay. Features include write protection of CMOS RAM or EEPROM, separate watchdog outputs, backup-battery switchover, and a RESET output that is valid with VCC down to 1V.
PAGE 2
MAX691A/MAX693A/MAX800L/MAX800M Microprocessor Supervisory Circuits ABSOLUTE MAXIMUM RATINGS Terminal Voltage (with respect to GND) VCC .......................................................................-0.3V to +6V VBATT...................................................................-0.3V to +6V All Other Inputs .....................................-0.3V to (VOUT + 0.3V) Input Current VCC Peak...........................................................................1.0A VCC Continuous.............
PAGE 3
Microprocessor Supervisory Circuits (MAX691A, MAX800L: VCC = +4.75V to +5.5V; MAX693A, MAX800M: VCC = +4.5V to +5.5V; VBATT = 2.8V, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER CONDITIONS MIN Battery Switchover Hysteresis TYP MAX 60 1 100 RESET AND WATCHDOG TIMER MAX691A, MAX800L 4.50 4.65 4.75 MAX693A, MAX800M 4.25 4.40 4.50 MAX800L, TA = +25°C, VCC falling 4.55 MAX800M, TA = +25°C, VCC falling 4.30 BATT ON Output Short-Circuit Current Reset Threshold Voltage ISINK = 3.
PAGE 4
MAX691A/MAX693A/MAX800L/MAX800M Microprocessor Supervisory Circuits ELECTRICAL CHARACTERISTICS (continued) (MAX691A, MAX800L: VCC = +4.75V to +5.5V; MAX693A, MAX800M: VCC = +4.5V to +5.5V; VBATT = 2.8V, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX 1.2 1.25 1.3 1.225 1.25 1.275 ±0.
PAGE 5
Microprocessor Supervisory Circuits 32 30 28 26 -30 0 30 60 90 1.5 1 0.5 120 150 40 -60 -30 0 30 60 90 -60 -30 120 150 90 120 150 180 VCC = 5V, VBATT = 0V 1.25 PFI THRESHOLD (V) 1.1 1.0 0.9 0.8 0 30 60 90 120 150 0.75 0.50 VCC = +5V, VBATT = 0V NO LOAD ON PFO 0 -60 -30 0 30 60 90 -60 120 150 -30 0 30 60 90 TEMPERATURE (°C) RESET THRESHOLD vs. TEMPERATURE RESET OUTPUT RESISTANCE vs. TEMPERATURE RESET DELAY vs. TEMPERATURE 4.55 4.50 4.45 4.
PAGE 6
____________________________Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) 8 4 0 1 2 3 4 10 RESET ACTIVE TIMEOUT PERIOD 1 SHORT WATCHDOG TIMEOUT PERIOD 10 100 VCC (V) 1000 VBATT to VOUT (mV) 100 SLOPE = 0.8Ω 8 4 1000 0 10 100 IOUT (mA) 6 100 VCC = 0V VBATT = 4.
PAGE 7
Microprocessor Supervisory Circuits PIN NAME FUNCTION 1 VBATT 2 VOUT Battery-Backup Input. Connect to external battery or capacitor and charging circuit. If backup battery is not used, connect to GND. Output Supply Voltage. When VCC is greater than VBATT and above the reset threshold, VOUT connects to VCC. When VCC falls below VBATT and is below the reset threshold, VOUT connects to VBATT. Connect a 0.1µF capacitor from VOUT to GND. Connect VOUT to VCC if no backup battery is used.
PAGE 8
MAX691A/MAX693A/MAX800L/MAX800M Microprocessor Supervisory Circuits WDI RESET MAX691A MAX693A 15 TO µP RESET WDO 1k t2 RESET t1 t1 t3 t1 = RESET TIMEOUT PERIOD t2 = NORMAL WATCHDOG TIMEOUT PERIOD t3 = WATCHDOG TIMEOUT PERIOD IMMEDIATELY AFTER RESET Figure 1. Adding an external pull-down resistor ensures –————– RESET is valid with VCC down to GND. Figure 2. Watchdog Timeout Period and Reset Active Time RESET and RESET are asserted when VCC falls below the reset threshold (4.
PAGE 9
Microprocessor Supervisory Circuits OSC SEL OSC IN Low Watchdog Timeout Period Reset Timeout Period Normal Immediately After Reset External Clock Input 1024 clks 4096 clks 2048 clks Low External Capacitor (600/47pF x C)ms (2.4/47pF x C)sec (1200/47pF x C)ms Floating Low 100ms 1.6sec 200ms Floating Floating 1.6sec 1.6sec 200ms EXTERNAL OSCILLATOR EXTERNAL CLOCK MAX691A MAX693A MAX800L MAX800M 8 7 8 OSC SEL 7 OSC IN OSC SEL OSC IN 50kHz INTERNAL OSCILLATOR 1.
PAGE 10
MAX691A/MAX693A/MAX800L/MAX800M Microprocessor Supervisory Circuits 5 BATT ON 4.65V* VCC 6 3 2 VBATT CE IN 1 13 12 MAX691A MAX693A MAX800L MAX800M OSC SEL WDI PFI RESET GENERATOR 7 15 TIMEBASE FOR RESET AND WATCHDOG 8 WATCHDOG TRANSITION DETECTOR 11 9 WATCHDOG TIMER 14 10 1.25V 4 GND * 4.4V FOR THE MAX693A/MAX800M Figure 4. MAX691A/MAX693A/MAX800L/MAX800M Block Diagram 5.0V VCC RESET 4.0V THRESHOLD 5.
PAGE 11
Microprocessor Supervisory Circuits VBATT +5V VCC MAX691A MAX693A MAX800L MAX800M 2.8V 2.0V to 5.5V CE OUT CE IN 50Ω OUTPUT IMPEDANCE VCC VBATT GND CLOAD MAX691A MAX693A MAX800L PFO PFI MAX800M LOW BATT GND Figure 6. CE Propagation Delay Test Circuit Figure 7. Low-Battery Indicator Table 2. Input and Output Status in Battery-Backup Mode Power-Fail Output The Power-Fail Output (PFO) goes low when PFI goes below 1.25V. It typically sinks 3.2mA with a saturation voltage of 0.1V.
PAGE 12
MAX691A/MAX693A/MAX800L/MAX800M Microprocessor Supervisory Circuits Battery-Backup Input The Battery-Backup Input (VBATT) is similar to the VCC input except the PMOS switch and parallel diode are much smaller. Accordingly, the on-resistances of the diode and the switch are each approximately 10Ω. Continuous current should be limited to 25mA and peak currents (only during power-up) limited to 250mA. The reverse leakage of this input is less than 1µA over temperature and supply voltage (Figure 8).
PAGE 13
Microprocessor Supervisory Circuits +5V CE CE VOUT CE IN MAX691A/MAX693A/MAX800L/MAX800M VIN Rp* R1 RAM 1 VCC C1* PFI CE OUT CE CE MAX691A MAX693A MAX800L MAX800M MAX691A MAX693A MAX800L MAX800M RAM 2 R3 R2 CE CE GND PFO RAM 3 GND TO µP CE *OPTIONAL 5V RAM 4 PFO CE 0V 0V VL VTRIP VH VIN VTRIP = 1.25 *MAXIMUM Rp VALUE DEPENDS ON THE NUMBER OF RAMS. MINIMUM Rp VALUE IS 1kΩ. ACTIVE-HIGH CE LINES FROM LOGIC Figure 10. Alternate CE Gating VH = 1.
PAGE 14
100 VCC = 5V TA = +25°C 0.1µF CAPACITOR FROM VOUT TO GND 80 MAX791-16 Backup-Battery Replacement MAXIMUM TRANSIENT DURATION (µs) MAX691A/MAX693A/MAX800L/MAX800M Microprocessor Supervisory Circuits 60 40 20 0 10 100 1000 10000 RESET COMPARATOR OVERDRIVE, (Reset Threshold Voltage - VCC) (mV) Figure 13. Maximum Transient Duration without Causing a Reset Pulse vs. Reset Comparator Overdrive parator. Select the ratio of R1 and R2 such that PFI sees 1.
PAGE 15
Microprocessor Supervisory Circuits MAX691A/MAX693A/MAX800L/MAX800M Maximum VCC Fall Time The VCC fall time is limited by the propagation delay of the battery switchover comparator and should not exceed 0.03V/µs. A standard rule of thumb for filter capacitance on most regulators is on the order of 100µF per amp of current. When the power supply is shut off or the main battery is disconnected, the associated initial VCC fall rate is just the inverse or 1A/100µF = 0.01V/µs.
PAGE 16
MAX691A/MAX693A/MAX800L/MAX800M Microprocessor Supervisory Circuits Ordering Information (continued) PART TEMP RANGE MAX693ACUE 0°C to +70°C 16 TSSOP MAX693ACSE 0°C to +70°C 16 Narrow SO MAX693ACWE MAX693ACPE MAX693AC/D 0°C to +70°C 0°C to +70°C 0°C to +70°C 16 Wide SO 16 Plastic DIP Dice* MAX693AEUE -40°C to +85°C ___________________Chip Topography VOUT PIN-PACKAGE VBATT RESET RESET VCC WDO 16 TSSOP MAX693AESE MAX693AEWE MAX693AEPE MAX693AEJE MAX693AMJE MAX800LCUE -40°C to +85°C -40°C
PAGE 17
Microprocessor Supervisory Circuits TSSOP4.40mm.EPS PACKAGE OUTLINE, TSSOP 4.40mm BODY 21-0066 G 1 1 ______________________________________________________________________________________ 17 MAX691A/MAX693A/MAX800L/MAX800M 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.
PAGE 18
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.) DIM A A1 B C e E H L N E H INCHES MILLIMETERS MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050 MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 SOICN .
PAGE 19
Microprocessor Supervisory Circuits DIM A A1 B C e E H L H E MAX MIN 0.104 0.093 0.012 0.004 0.019 0.014 0.013 0.009 0.050 0.299 0.291 0.394 0.419 0.050 0.016 SOICW.EPS INCHES N MILLIMETERS MIN 2.35 0.10 0.35 0.23 MAX 2.65 0.30 0.49 0.32 1.27 7.40 7.60 10.00 10.65 0.40 1.27 VARIATIONS: 1 INCHES TOP VIEW DIM D D D D D D A B e MIN 0.398 0.447 0.496 0.598 0.697 MAX 0.413 0.463 0.512 0.614 0.713 MILLIMETERS MIN 10.10 11.35 12.60 15.20 17.70 MAX 10.50 11.75 13.00 15.60 18.