DS1707ESA+T&R - Hytronics - Datasheet.Live

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FEATURES

§ 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

§ 20% tolerance compatible with 3.0V systems

§ Pin compatible with the MAXIM

MAX707/MAX708 in 8-pin DIP, 8-pin SOIC

packages

§ 8-pin DIP, 8-pin and m-SOP SOIC and 8-pin

m-SOP packages available

§ Industrial temperature range -40°C to +85°C

PIN ASSIGNMENT

See Mech. Drawings Section on website

DS1707 and DS1708_R/S/T

PIN DESCRIPTION

PBRST - Pushbutton Reset Input

VCC - Power Supply

GND - Ground

IN - Input

NMI - Non-maskable Interrupt

NC - No Connect

RST - Active Low Reset Output

RST - Active High Reset Output

DESCRIPTION

The DS1707/DS1708 3.3- or 5.0-Volt MicroMonitor monitors three vital conditions for a microprocessor:

power supply, voltage sense, and external override. A precision temperature-compensated reference and

comparator circuit monitor the status of VCC 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

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.

DS1707/DS1708

3.3 and 5.0-

olt MicroMonito

www.maxim-ic.com

8-Pin DIP (300-mil)

PBRST

VCC

GND

RST

NMI

8-Pin

-SOP (118-mil)

RST

PBRST

VCC

NMI

GND

8-Pin SOIC (150-mil)

PBRST

VCC

GND

RST

NMI

DS1707/DS1708

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The third function the DS1707/DS1708 performs is pushbutton reset control. The DS1707/DS1708

debounces the pushbutton input and guarantees an active reset pulse width of 130 ms minimum.

OPERATION

Power Monitor

The DS1707/DS1708 detects out-of-tolerance power supply conditions and warns a processor-based

system of impending power failure. When VCC falls below the minimum VCC tolerance, a comparator

outputs the RST and RST signals. RST and RST are excellent control signals for a microprocessor, as

processing is stopped at the last possible moment of valid VCC. On power-up, RST and RST are kept

active for a minimum of 130 ms to allow the power supply and processor to stabilize.

Pushbutton Reset

The DS1707/DS1708 provides an input pin for direct connection to a pushbutton reset (see Figure 2). The

pushbutton reset input requires an active low signal. Internally, this input is debounced and timed such

that RST and RST signals of at least 130 ms minimum will be generated. The 130 ms delay commences

as the pushbutton reset input is released from the low level. The pushbutton can be initiated by connecting

the NMI output to the PBRST input as shown in Figure 3.

Non-Maskable Interrupt

The DS1707/DS1708 generates a non-maskable interrupt ( NMI ) for early warning of a power failure. A

precision comparator monitors the voltage level at the IN pin relative to an on-chip reference generated

by an internal band gap. The IN pin is a high impedance input allowing for a user-defined sense point. An

external resistor voltage divider network (Figure 5) is used to interface with high voltage signals. This

sense point may be derived from a regulated supply or from a higher DC voltage level closer to the main

system power input. Since the IN trip point VTP is 1.25 volts, the proper values for R1 and R2 can be

determined by the equation as shown in Figure 5. Proper operation of the DS1707/DS1708 requires that

the voltage at the IN pin be limited to VCC. Therefore, the maximum allowable voltage at the supply being

monitored (VMAX) can also be derived as shown in Figure 5. A simple approach to solving the equation is

to select a value for R2 high enough to keep power consumption low, and solve for R1. The flexibility of

the IN input pin allows for detection of power loss at the earliest point in a power supply system,

maximizing the amount of time for system shut-down between NMI and RST/ RST .

When the supply being monitored decays to the voltage sense point, the DS1707/DS1708 pulses the NMI

output to the active state for a minimum 200 ms. The NMI power-fail detection circuitry also has built-in

hysteresis of 100 mV. The supply must be below the voltage sense point for approximately 5 ms before a

low NMI will be generated. In this way, power supply noise is removed from the monitoring function,

preventing false interrupts. During a power-up, any detected IN pin levels below VTP by the comparator

are disabled from generating an interrupt until VCC rises to VCCTP. As a result, any potential NMI pulse

will not be initiated until VCC reaches VCCTP.

Connecting NMI to PBRST would allow the non-maskable interrupt to generate an automatic reset when

an out-of-tolerance condition occurred in a monitored supply. An example is shown in Figure 3.

DS1707/DS1708

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MICROMONITOR BLOCK DIAGRAM Figure 1

40kW

PUSHBUTTON RESET Figure 2

PUSHBUTTON RESET CONTROLLED BY NMI Figure 3

DS1707/DS1708

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TIMING DIAGRAM: PUSHBUTTON RESET Figure 4

NON-MASKABLE INTERRUPT CIRCUIT EXAMPLE Figure 5

SENSE = R2

R2 R1+ X 1.25 VMAX =

SENSE

V X VCC

Example: VSENSE = 4.50V at the trip point

CC = 3.3V

10 kΩ = R2

Therefore:

25.1

50.4 X 3.3 = 11.88V maximum

4.50 =

10k R1 + X 1.25 R1 = 26 kΩ

DS1707/DS1708

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TIMING DIAGRAM: NON-MASKABLE INTERRUPT Figure 6

TIMING DIAGRAM: POWER-DOWN Figure 7

DS1707/DS1708

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TIMING DIAGRAM: POWER UP Figure 8

DS1707/DS1708

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ABSOLUTE MAXIMUM RATINGS*

Voltage on VCC Pin Relative to Ground -0.5V to +7.0V

Voltage on I/O Relative to Ground** -0.5V to VCC + 0.5V

Operating Temperature -40°C to +85°C

Storage Temperature -55°C to +125°C

Soldering Temperature 260°C for 10 seconds

* This is a stress rating only and functional operation of the device at these or any other conditions

above those indicated in the operation sections of this specification is not implied. Exposure to

absolute maximum rating conditions for extended periods of time may affect reliability.

** The voltage input limits on IN and PBRST can be exceeded if the input current is less than 10 mA.

RECOMMENDED DC OPERATING CONDITIONS (-40°C to +85°C)

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Supply Voltage VCC 1.2 5.5 V 1

PBRST Input High Level VIH 2.0

VCC-0.5

CC+0.3 V 1, 3

1, 4

PBRST Input Low Level VIL -0.03 +0.5 V 1

DC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC=1.2V to 5.5V)

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

VCC Trip Point DS1707 VCCTP 4.50 4.65 4.75 V 1

VCC Trip Point DS1708 VCCTP 4.25 4.40 4.50 V 1

VCC Trip Point DS1708T VCCTP 3.00 3.08 3.15 V 1

VCC Trip Point DS1708S VCCTP 2.85 2.93 3.00 V 1

VCC Trip Point DS1708R VCCTP 2.55 2.63 2.70 V 1

Input Leakage IIL -1.0 +1.0

mA 2

Output Current @ 2.4V IOH 350

mA 3

Output Current @ 0.4V IOL 10 mA 3

Output Voltage @ -500µA VOH V

CC-0.3 VCC-0.1 V 3

Operating Current @ VCC < 5.5V ICC 60

mA 5

Operating Current @ VCC < 3.6V ICC 50

mA 5

IN Input Trip Point VTP 1.20 1.25 1.30 V 1

CAPACITANCE (tA=25°C)

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Input Capacitance CIN 5 pF

Output Capacitance COUT 7 pF

DS1707/DS1708

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AC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC=1.2V to 5.5V)

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

PBRST = VIL tPB 150 ns

Reset Active Time tRST 130 205 285 ms

VCC Detect to RST and RST tRPD 5 8

ms 7

VCC Slew Rate tF 20 ms

VCC Detect to RST and RST tRPU 130 205 285 ms 6

VCC Slew Rate tR 0 ns

PBRST Stable Low to RST and RST tPDLY 250 ns

VIN Detect to NMI tIPD 5 8

ms 7

NOTES:

1. All voltages are referenced to ground.

2. PBRST is internally pulled up to VCC with an internal impedance of 40 kW typical.

3. VCC ≥ 2.4V

4. VCC < 2.4V

5. Measured with outputs open and all inputs at VCC or ground.

6. tR = 5 ms

7. Noise immunity - pulses < 2 ms at VCCTP minimum will not cause a reset.

DS1707/DS1708

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PART MARKING CODES

cccccc

###xx

8-pin DIP

(300 MIL)

8-pin SOIC

(150 MIL)

8-pin µSOP

(118 MIL)

DS170AB

yywwrv

###xx

DS170AB

yywwrv

###xx

170AB

ywwrv

Brand Codes

Code Description Values

AB Device type and tolerance 7_, 8_, 8R, 8S, 8T (where’_’ is a blank)

yww or yyww Date Code. Identifies the year and

work week the device was

assembled.

y, the last digit of the year.

yy, the last two digits of the year.

ww, the work week (values 01 through 52).

rv Die Revision A letter followed by a number (eg. B1)

###xx Lot Code Three numbers followed by 2 letters

cccccc Country of Assembly Abbreviation of country name.

DS1707/DS1708

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ORDERING INFORMATION

ORDERING

NUMBER

PACKAGE OPERATING

TEMPERATURE

VERSION

DS1707EPA 8-pin DIP (300mil) -40°C TO +85°C 5V-5% MONITOR, /RST, RST

DS1707ESA 8-pin SOIC (150 mil) -40°C TO +85°C 5V-5% MONITOR, /RST, RST

DS1707EUA 8-pin µSOP (118 mil) -40°C TO +85°C 5V-5% MONITOR, /RST, RST

DS1708EPA 8-pin DIP (300mil) -40°C TO +85°C 5V-10% MONITOR, /RST, RST

DS1708ESA 8-pin SOIC (150 mil) -40°C TO +85°C 5V-10% MONITOR, /RST, RST

DS1708EUA 8-pin µSOP (118 mil) -40°C TO +85°C 5V-10% MONITOR, /RST, RST

DS1708REPA 8-pin DIP (300mil) -40°C TO +85°C 3.3V-20% MONITOR, /RST, RST

DS1708RESA 8-pin SOIC (150 mil) -40°C TO +85°C 3.3V-20% MONITOR, /RST, RST

DS1708REUA 8-pin µSOP (118 mil) -40°C TO +85°C 3.3V-20% MONITOR, /RST, RST

DS1708SEPA 8-pin DIP (300mil) -40°C TO +85°C 3.3V-10% MONITOR, /RST, RST

DS1708SESA 8-pin SOIC (150 mil) -40°C TO +85°C 3.3V-10% MONITOR, /RST, RST

DS1708SEUA 8-pin µSOP (118 mil) -40°C TO +85°C 3.3V-10% MONITOR, /RST, RST

DS1708TEPA 8-pin DIP (300mil) -40°C TO +85°C 3.3V-5% MONITOR, /RST, RST

DS1708TESA 8-pin SOIC (150 mil) -40°C TO +85°C 3.3V-5% MONITOR, /RST, RST

DS1708TEUA 8-pin µSOP (118 mil) -40°C TO +85°C 3.3V-5% MONITOR, /RST, RST

*Contact factory for availability of Pb-free versions.

E = -40°C to +85°C temperature range

A = 8 lead device

P = Plastic DIP (300 mil)

S = SOIC (150 mil)

U = µSOP (118 mil)

ENGLISH • ???? • ??? • ???

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DS1707

Part Number Table

Notes:

See the DS1707 QuickView Data Sheet for further information on this product family or download the DS1707 full data sheet

(PDF, 192kB).

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.2.

Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business

day.

Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: See full data sheet or

Part Naming Conventions.

* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses.5.

Part Number

Notes

Free

Sample

Buy

Direct

Package:

TYPE PINS SIZE

DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?

Materials Analysis

DS1707EPA

5V-5%

Monitor

PDIP;8 pin;300

Dwg: 56-G5005-000A (PDF)

Use pkgcode/variation: P8-7*

-40C to +85C

RoHS/Lead-Free: No

Materials Analysis

DS1707EPA+

PDIP;8 pin;300

Dwg: 56-G5005-000A (PDF)

Use pkgcode/variation: P8+7*

-40C to +85C

RoHS/Lead-Free: Yes

Materials Analysis

DS1707ESA+

SOIC;8 pin;150

Dwg: 56-G2008-001C (PDF)

Use pkgcode/variation: S8+2*

-40C to +85C

RoHS/Lead-Free: Yes

Materials Analysis

DS1707ESA+T&R

5V-5%

SOIC;8 pin;150

Dwg: 56-G2008-001C (PDF)

Use pkgcode/variation: S8+2*

-40C to +85C

RoHS/Lead-Free: Yes

Materials Analysis

DS1707ESA/T&R

5V-5%

SOIC;8 pin;150

Dwg: 56-G2008-001C (PDF)

Use pkgcode/variation: S8-2*

-40C to +85C

RoHS/Lead-Free: No

Materials Analysis

DS1707ESA

5V-5%

Monitor

SOIC;8 pin;150

Dwg: 56-G2008-001C (PDF)

Use pkgcode/variation: S8-2*

-40C to +85C

RoHS/Lead-Free: No

Materials Analysis

DS1707EUA+

uSOP;8 pin;118

Dwg: 21-0036J (PDF)

Use pkgcode/variation: U8+1*

-40C to +85C

RoHS/Lead-Free: Yes

Materials Analysis

DS1707EUA/T&R

5V-5%

uSOP;8 pin;118

Dwg: 21-0036J (PDF)

Use pkgcode/variation: U8-1*

-40C to +85C

RoHS/Lead-Free: No

Materials Analysis

DS1707EUA

5V-5%

Monitor

uSOP;8 pin;118

Dwg: 21-0036J (PDF)

Use pkgcode/variation: U8-1*

-40C to +85C

RoHS/Lead-Free: No

Materials Analysis

DS1707EUA+T&R

5V-5%

uSOP;8 pin;118

Dwg: 21-0036J (PDF)

Use pkgcode/variation: U8+1*

-40C to +85C

RoHS/Lead-Free: Yes

Materials Analysis

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