Datasheet

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

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FEATURES

 Halts and restarts an out-of-control

microprocessor

 Holds microprocessor in check during power

transients

 Automatically restarts microprocessor after

power failure

 Monitors pushbutton for external override

 Accurate 5%, 10% or 20% resets for 3.3V

systems and 5% or 10% resets for 5.0V

systems

 Eliminates the need for discrete components

 3.3V 20% tolerance for use with 3.0V

systems

 Pin-compatible with the MAXIM

MAX705/MAX706 in 8-pin DIP, 8-pin SOIC,

and -SOP

 8-pin DIP, 8-pin SOIC and 8-pin -SOP

packages

 Industrial temperature range -40C to +85C

PIN ASSIGNMENT

DS1705 and DS1706_R/S/T

(*DS1706L and DS1706P)

PIN DESCRIPTION

PBRST - Pushbutton Reset Input

- Power Supply

GND - Ground

IN - Input

NMI - Non-maskable Interrupt

ST - Strobe Input

RST - Active Low Reset Output

*RST - Active High Reset Output

(DS1706P and DS1706L only)

WDS - Watchdog Status Output

DESCRIPTION

The DS1705/DS1706 3.3- or 5.0-Volt MicroMonitor monitors three vital conditions for a microprocessor:

power supply, software execution, and external override. A precision temperature compensated reference

and comparator circuit monitor the status of V

at the device and at an upstream point for maximum

protection. When the sense input detects an out-of-tolerance condition, a non-maskable interrupt is

generated. As the voltage at the device degrades, an internal power fail signal is generated which forces

DS1705/DS1706

3.3V and 5.0V MicroMonito

19-5212; Rev 4/10

www.maxim-ic.com

8-Pin



-SOP (118-mil)

See Mech. Drawings Section on website

RST(*RST)

WDS

PBRST

NMI

GND

8-Pin DIP (300 -mil)

PBRST

GND

WDS

RST

NMI

8-Pin SOIC (150-mil)

PBRST

GND

WDS

RST(*RST)

NMI

Summary of content (12 pages)

PAGE 1
9-5212; Rev 4/10 DS1705/DS1706 3.3V and 5.0V MicroMonitor www.maxim-ic.com FEATURES           PIN ASSIGNMENT Halts and restarts an out-of-control microprocessor Holds microprocessor in check during power transients Automatically restarts microprocessor after power failure Monitors pushbutton for external override Accurate 5%, 10% or 20% resets for 3.3V systems and 5% or 10% resets for 5.0V systems Eliminates the need for discrete components 3.3V 20% tolerance for use with 3.
PAGE 2
DS1705/DS1706 the reset to an active state. When VCC returns to an in-tolerance condition, the reset signal is kept in the active state for a minimum of 130 ms to allow the power supply and processor to stabilize. The second function the DS1705/DS1706 performs is pushbutton reset control. The DS1705/DS1706 debounces the pushbutton input and guarantees an active reset pulse width of 130 ms minimum. The third function is a watchdog timer.
PAGE 3
DS1705/DS1706 Watchdog Timer The watchdog timer function forces WDS signals active when the ST input is not clocked within the 1 second time-out period. Time-out of the watchdog starts when RST (or RST) becomes inactive. If a highto-low transition occurs on the ST input pin prior to time-out, the watchdog timer is reset and begins to time out again. If the watchdog timer is allowed to time out, the WDS signal is driven active (low) for a minimum of 130 ms.
PAGE 4
DS1705/DS1706 PUSH-BUTTON RESET CONTROLLED BY NMI AND WDS Figure 3 TIMING DIAGRAM: PUSHBUTTON RESET Figure 4 NON-MASKABLE INTERRUPT CIRCUIT EXAMPLE Figure 5 VSENSE = R1 R2 X 1.25 R2 Example: Therefore: VMAX = VSENSE X VCC VTP VSENSE = 4.50V at the trip point VCC = 3.3V 10 kΩ = R2 4.50 X 3.3 = 11.88V maximum 1.25 4.5 = R1  10k X 1.
PAGE 5
DS1705/DS1706 WATCHDOG TIMER Figure 6 TIMING DIAGRAM: STROBE INPUT Figure 7 TIMING DIAGRAM: NON-MASKABLE INTERRUPT Figure 8 5 of 12
PAGE 6
DS1705/DS1706 TIMING DIAGRAM: POWER-DOWN Figure 9 6 of 12
PAGE 7
DS1705/DS1706 TIMING DIAGRAM: POWER-UP Figure 10 7 of 12
PAGE 8
DS1705/DS1706 ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC Pin Relative to Ground Voltage Range on I/O Relative to Ground* Operating Temperature Range Storage Temperature Range Lead Temperature (soldering, 10s) Soldering Temperature (reflow) Lead(Pb)-free Containing lead(Pb) -0.5V to +7.0V -0.5V to (VCC + 0.
PAGE 9
DS1705/DS1706 AC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL (VCC = 1.2V to 5.5V, TA = -40C to +85C.) MIN TYP MAX UNITS NOTES tPB 150 Reset Active Time tRST 130 Pulse Width tST 10 PBRST ST = VIL VCC Detect to RST and RST VCC Slew Rate VCC Detect to RST and RST VCC Slew Rate PBRST Stable Low to RST and RST tRPD ns 205 5 tF 20 tRPU 130 tR 0 tTD VIN Detect to NMI tIPD 1.0 8 ms ns 6 s 9 s 205 285 ms 7 ns tPDLY Watchdog Timeout 285 250 ns 1.6 2.
PAGE 10
DS1705/DS1706 PART MARKING CODES DS170AB yywwrv 8-pin DIP (300 MIL) 8-pin SOIC (150 MIL) 8-pin µSOP (118 MIL) CODE AB yww or yyww rv ###xx cccccc cccccc ###xx DS170AB yywwrv ###xx cccccc 170AB ywwrv ###xx BRAND CODES DESCRIPTION VALUES Device type and tolerance 5_, 6_, 6L, 6P, 6R, 6S, 6T (where’_’ is a blank) Date Code. Identifies the year and work y, the last digit of the year. week the device was assembled. yy, the last two digits of the year. ww, the work week (values 01 through 52).
PAGE 11
DS1705/DS1706 ORDERING INFORMATION PART DS1705EPA DS1705ESA DS1705EUA DS1706EPA DS1706ESA DS1706EUA DS1706LEPA DS1706LESA DS1706LEUA DS1706PEPA DS1706PESA DS1706PEUA DS1706REPA DS1706RESA DS1706REUA DS1706SEPA DS1706SESA DS1706SEUA DS1706TEPA DS1706TESA DS1706TEUA TEMP RANGE -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to
PAGE 12
DS1705/DS1706 REVISION HISTORY REVISION DATE DESCRIPTION PAGES CHANGED 4/10 Added the lead temperature and updated the soldering temperature in the Absolute Maximum Ratings; corrected Note 9. 8, 9 12 of 12 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.