LM3710XQMMX-308/NOPB - National Semiconductor

LM3710/LM3711

Microprocessor Supervisory Circuits with Power Fail

Input, Low Line Output, Manual Reset and Watchdog

Timer

General Description

The LM3710/LM3711 series of microprocessor supervisory

circuits provide the maximum flexibility for monitoring power

supplies and battery controlled functions in systems without

backup batteries. The LM3710/LM3711 series are available

in MSOP-10 and 9-bump micro SMD packages.

Built-in features include the following:

Reset: Reset is asserted during power-up, power-down, and

brownout conditions. RESET is guaranteed down to V

1.0V.

Manual Reset Input: An input that asserts reset when pulled

low.

Power-Fail Input: A 1.225V threshold detector for power fail

warning, or to monitor a power supply other than V

Low Line Output: This early power failure warning indicator

goes low when the supply voltage drops to a value which is

2% higher than the reset threshold voltage.

Watchdog Timer: The WDI (Watchdog Input) monitors one of

the µP’s output lines for activity. If no output transition occurs

during the watchdog timeout period, reset is activated.

Features

nStandard Reset Threshold voltage: 3.08V

nCustom Reset Threshold voltages: For other voltages

between 2.2V and 5.0V in 10mV increments, contact

National Semiconductor Corp.

nNo external components required

nManual-Reset input

nRESET (LM3710) or RESET (LM3711) outputs

nPrecision supply voltage monitor

nFactory programmable Reset and Watchdog Timeout

Delays

nSeparate Power Fail comparator

nAvailable in micro SMD package for minimum footprint

n±0.5% Reset threshold accuracy at room temperature

n±2% Reset threshold accuracy over temperature

extremes

nReset assertion down to 1V V

(RESET option only)

n28 µA V

supply current

Applications

nEmbedded Controllers and Processors

nIntelligent Instruments

nAutomotive Systems

nCritical µP Power Monitoring

Typical Application

20011803

January 2005

LM3710/LM3711 Microprocessor Supervisory Circuits with Power Fail Input, Low Line Output,

Manual Reset and Watchdog Timer

Connection Diagram

MSOP-10

Top View

(looking from the coating side)

micro SMD 9 Bump Package

BPA09

20011802 20011801

Pin Descriptions

Pin No.

Name Function

micro

SMD MSOP

A1 2 MR Manual-Reset input. When MR is less than V

MRT

(Manual Reset Threshold)

RESET/RESET is engaged.

B1 1 V

Power Supply input.

C1 10 RESET Reset Logic Output. Pulses low for t

(Reset Timeout Period) when triggered, and stays

low whenever V

is below the reset threshold or when MR is below V

MRT

. It remains low

for t

after either V

rises above the reset threshold, or after MR input rises above

MRT

(LM3710 only).

RESET Reset Logic Output. RESET is the inverse of RESET (LM3711 only).

C2 8 PFO Power-Fail Logic Output. When PFI is below V

PFT

, PFO goes low; otherwise, PFO

remains high.

C3 7 LLO Low-Line Logic Output. Early Power-Fail warning output. Low when V

falls below V

LLOT

(Low-Line Output Threshold). This output can be used to generate an NMI (Non-Maskable

Interrupt) to provide an early warning of imminent power-failure.

B3 5 GND Ground reference for all signals.

A3 4 WDI Watchdog Input Transition Monitor: If no transition activity occurs for a period exceeding

(Watchdog Timeout Period), reset is engaged.

A2 3 PFI Power-Fail Comparator Input. When PFI is less than V

PFT

(Power-Fail Reset Threshold),

the PFO goes low; otherwise, PFO remains high.

B2 6, 9 NC No Connect. Test input used at factory only. Leave floating.

LM3710/LM3711

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Block Diagram

20011805

LM3710/LM3711

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Ordering Information

20011804

*For other voltages between 2.2V and 5.0V, please contact National Semiconductor sales office.

LM3710/LM3711

Part Number Output

Reset

Timeout

Period

Watchdog

Timeout

Period

Package Package

Marking

MSOP micro

SMD

LM3710XKBP-232 totem-pole 28ms 102ms x %%I19

LM3710XKBPX-232 totem-pole 28ms 102ms x %%I19

LM3710XKBP-463 totem-pole 28ms 102ms x %%I21

LM3710XKBPX-463 totem-pole 28ms 102ms x %%I21

LM3710XKMM-232 totem-pole 28ms 102ms x R72B

LM3710XKMMX-232 totem-pole 28ms 102ms x R72B

LM3710XKMM-463 totem-pole 28ms 102ms x R74B

LM3710XKMMX-463 totem-pole 28ms 102ms x R74B

LM3710XNMM-450 totem-pole 1.4ms 1600ms x R84B

LM3710XNMMX-450 totem-pole 1.4ms 1600ms x R84B

LM3710XNMM-470 totem-pole 1.4ms 1600ms x R83B

LM3710XNMMX-470 totem-pole 1.4ms 1600ms x R83B

LM3710XQBP-308 totem-pole 200ms 1600ms x %%IA

LM3710XQBPX-308 totem-pole 200ms 1600ms x %%IA

LM3710YQMM-232 open-drain 200ms 1600ms x R77B

LM3710YQMMX-232 open-drain 200ms 1600ms x R77B

LM3711XKBP-232 totem-pole 28ms 102ms x %%I20

LM3711XKBPX-232 totem-pole 28ms 102ms x %%I20

LM3711XKBP-463 totem-pole 28ms 102ms x %%I22

LM3711XKBPX-463 totem-pole 28ms 102ms x %%I22

LM3711XKMM-232 totem-pole 28ms 102ms x R73B

LM3711XKMMX-232 totem-pole 28ms 102ms x R73B

LM3711XKMM-463 totem-pole 28ms 102ms x R75B

LM3711XKMMX-463 totem-pole 28ms 102ms x R75B

LM3710XQMM-308 totem-pole 200ms 1600ms x R37B

LM3710/LM3711

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Ordering Information (Continued)

LM3710/LM3711 (Continued)

Part Number Output

Reset

Timeout

Period

Watchdog

Timeout

Period

Package Package

Marking

MSOP micro

SMD

LM3710XQMMX-308 totem-pole 200ms 1600ms x R37B

LM3711XQBP-308 totem-pole 200ms 1600ms x %%IB

LM3711XQBPX-308 totem-pole 200ms 1600ms x %%IB

LM3711XQMM-308 totem-pole 200ms 1600ms x R38B

LM3711XQMMX-308 totem-pole 200ms 1600ms x R38B

%% is the datecode and will vary with time.

Table Of Functions

Part

Number

Active

Low

Reset

Active

High

Reset

Output

(X = totem-pole)

(Y = open-drain)

Reset

Timeout

Period

Watchdog

Timeout

Period

Manual

Reset

Power Fail

Comparator

Low

Line

Output

LM3710 x X, Y* Customized Customized x x x

LM3711 x X Customized Customized x x x

* = available upon request. Contact National

LM3710/LM3711

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Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

Supply Voltage (V

) −0.3V to 6.0V

All Other Inputs −0.3V to V

+ 0.3V

ESD Ratings (Note 2)

Human Body Model

Machine Model

1.5kV

150V

Power Dissipation (Note 3)

Operating Ratings (Note 1)

Temperature Range −40˚C ≤T

≤85˚C

LM3710/LM3711 Series Electrical Characteristics

Limits in the standard typeface are for T

= 25˚C and limits in boldface type apply over full operating range. Unless otherwise

specified: V

= +2.2V to 5.5V.

Symbol Parameter Conditions Min Typ Max Units

POWER SUPPLY

Operating Voltage

Range: V

LM3710 1.0 5.5 V

LM3711 1.2 5.5

Supply

Current

All inputs = V

; all outputs floating 28 50 µA

RESET THRESHOLD

RST

Reset Threshold V

falling −0.5

−2 V

RST

+0.5

+2 %

falling: T

= 0˚C to 70˚C −1.5 +1.5

RSTH

Reset Threshold

Hysteresis

0.0032•V

RST

Reset Timeout

Period

Reset Timeout Period = E, J, N, S

Reset Timeout Period = F, K, P, T

Reset Timeout Period = G, L, Q, U

Reset Timeout Period = H, M, R, V

140

1120

1.4

200

1600

280

2240

to Reset

Delay

falling at 1mV/µs 20 µs

RESET (LM3711)

RESET V

>2.25V, I

SINK

= 900µA 0.3

>2.7V, I

SINK

= 1.2mA 0.3

>4.5V, I

SINK

= 3.2mA 0.4

RESET V

>1.2V, I

SOURCE

= 50µA 0.8 V

>1.8V, I

SOURCE

= 150µA 0.8 V

>2.25V, I

SOURCE

= 300µA 0.8 V

>2.7V, I

SOURCE

= 500µA 0.8 V

>4.5V, I

SOURCE

= 800µA V

− 1.5V

LKG

Output Leakage

Current

RESET

= 5.5V 1.0 µA

RESET (LM3710)

RESET V

>1.0V, I

SINK

= 50µA 0.3

>1.2V, I

SINK

= 100µA 0.3

>2.25V, I

SINK

= 900µA 0.3

>2.7V, I

SINK

= 1.2mA 0.3

>4.5V, I

SINK

= 3.2mA 0.4

RESET V

>2.25V, I

SOURCE

= 300µA 0.8 V

>2.7V, I

SOURCE

= 500µA 0.8 V

>4.5V, I

SOURCE

= 800µA V

− 1.5V

LM3710/LM3711

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LM3710/LM3711 Series Electrical Characteristics (Continued)

Limits in the standard typeface are for T

= 25˚C and limits in boldface type apply over full operating range. Unless otherwise

specified: V

= +2.2V to 5.5V.

Symbol Parameter Conditions Min Typ Max Units

WDI

WDI Watchdog Input

Current

−1 +1 µA

WDI

Watchdog Input

Threshold 0.2•V

1.225 0.8•V

Watchdog

Timeout Period

Watchdog Timeout Period = E, F, G, H

Watchdog Timeout Period = J, K, L, M

Watchdog Timeout Period = N, P, Q, R

Watchdog Timeout Period = S, T, U, V

4.3

1120

17900

6.2

102

1600

25600

9.3

153

2400

38400

PFI/MR

PFT

PFI Input

Threshold

1.200 1.225 1.250 V

MRT

MR Input

Threshold

MR, Low 0.8 V

MR, High 2.0

PFTH

MRTH

PFI/MR Threshold

Hysteresis

PFI/MR falling: V

RST MAX

to 5.5V 0.0032•V

RST

PFI

Input Current

(PFI only)

−75 75 nA

MR Pull-up

Resistance

35 56 75 kΩ

MR to Reset

Delay

12 µS

MR Pulse Width 25 µS

PFO, LLO

PFO, LLO Output

Voltage

>2.25V, I

SINK

= 900µA 0.3

>2.7V, I

SINK

= 1.2mA 0.3

>4.5V, I

SINK

= 3.2mA 0.4

>2.25V, I

SOURCE

= 300µA 0.8 V

>2.7V, I

SOURCE

= 500µA 0.8 V

>4.5V, I

SOURCE

= 800µA V

− 1.5V

LLO OUTPUT

LLOT

LLO Output

Threshold

LLO

−V

RST

falling)

1.01•V

RST

1.02•V

RST

1.03•V

RST

LLOTH

Low-Line

Comparator

Hysteresis

0.0032•V

RST

Low-Line

Comparator Delay

falling at 1mV/µs 20 µs

LM3710/LM3711

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LM3710/LM3711 Series Electrical Characteristics (Continued)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device

is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.

The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the

listed conditions.

Note 2: The Human Body model is a 100 pF capacitor discharged through a 1.5 kΩresistor into each pin. The machine model is a 200pF capacitor discharged

directly into each pin.

Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, θJ-A,

and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperture is calculated using:

Where the value of θJ-A for the MSOP-10 package is 195˚C/W in a typical PC board mounting and the micro SMD package is 220˚C/W.

LM3710/LM3711

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Typical Performance Characteristics

Supply Current vs Supply Voltage 3.3V Supply Current vs Temperature

20011815

20011811

Normalized Reset Threshold Voltage vs Temperature Reset Timeout Period vs V

20011812

20011832

Reset Timeout Period vs Temperature

Max. Transient Duration vs Reset Comparator Overdrive

= 3.3V)

20011810

20011816

LM3710/LM3711

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Typical Performance Characteristics (Continued)

Watchdog Timeout Period vs Temperature

programmed as 6.2ms) Low-Line Comparator Propagation Delay vs Temperature

20011813

20011814

LM3710/LM3711

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Circuit Information

RESET OUTPUT

The Reset input of a µP initializes the device into a known

state. The LM3710/LM3711 microprocessor supervisory cir-

cuits assert a forced reset output to prevent code execution

errors during power-up, power-down, and brownout condi-

tions.

RESET is guaranteed valid for V

>1V. Once V

ex-

ceeds the reset threshold, an internal timer maintains the

output for the reset timeout period. After this interval, reset

goes high. The LM3710 offers an active-low RESET; The

LM3711 offers an active-high RESET.

Any time V

drops below the reset threshold (such as

during a brownout), the reset activates. When V

again

rises above the reset threshold, the internal timer starts.

Reset holds until V

exceeds the reset threshold for longer

than the reset timeout period. After this time, reset releases.

The Manual Reset input (MR) will initiate a forced reset also.

See the Manual Reset Input section.

RESET THRESHOLD

The LM3710/LM3711 family is available with a reset voltage

of 3.08V. Other reset thresholds in the 2.20V to 5.0V range,

in steps of 10 mV, are available; contact National Semicon-

ductor for details.

MANUAL RESET INPUT (MR)

Many µP-based products require a manual reset capability,

allowing the operator to initiate a reset. The MR input is fully

debounced and provides an internal 56 kΩpull-up. When the

MR input is pulled below V

MRT

(1.225V) for more than 25 µs,

reset is asserted after a typical delay of 12 µs. Reset remains

active as long as MR is held low, and releases after the reset

timeout period expires after MR rises above V

MRT

. Use MR

with digital logic to assert or to daisy chain supervisory

circuits. It may be used as another low-line comparator by

adding a buffer.

POWER-FAIL COMPARATOR (PFI/PFO)

The PFI is compared to a 1.225V internal reference, V

PFT

.If

PFI is less than V

PFT

, the Power Fail Output PFO drops low.

The power-fail comparator signals a falling power supply,

and is driven typically by an external voltage divider that

senses either the unregulated supply or another system

supply voltage. The voltage divider generally is chosen so

the voltage at PFI drops below V

PFT

several milliseconds

before the main supply voltage drops below the reset thresh-

old, providing advanced warning of a brownout.

The voltage threshold is set by R

and R

and is calculated

as follows:

Note this comparator is completely separate from the rest of

the circuitry, and may be employed for other functions as

needed.

LOW-LINE OUTPUT (LLO)

The low-line output comparator is typically used to provide a

non-maskable interrupt to a µP when V

begins falling. LLO

monitors V

and goes low when V

falls below V

LLOT

(typically 1.02 •V

RST

) with hysteresis of 0.0032 •V

RST

WATCHDOG TIMER INPUT (WDI)

The watchdog timer input monitors one of the microproces-

sor’s output lines for activity. Each time a transition occurs on

this monitored line, the watchdog counter is reset. However,

if no transition occurs and the timeout period is reached, the

LM3710/LM3711 assumes that the microprocessor has

locked up and the reset output is activated.

WDI is a high impedance input.

SPECIAL PRECAUTIONS FOR THE MICRO SMD

PACKAGE

As with most integrated circuits, the LM3710 and LM3711

are sensitive to exposure from visible and infrared (IR) light

radiation. Unlike a plastic encapsulated IC, the micro SMD

package has very limited shielding from light, and some

sensitivity to light reflected from the surface of the PC board

or long wavelength IR entering the die from the side may be

experienced. This light could have an unpredictable affect on

the electrical performance of the IC. Care should be taken to

shield the device from direct exposure to bright visible or IR

light during operation.

MICRO SMD MOUNTING

The micro SMD package requires specific mounting tech-

niques which are detailed in National Semiconductor Appli-

cation Note AN-1112. Referring to the section Surface

Mount Technology (SMT) Assembly Considerations,it

should be noted that the pad style which must be used with

the 9-pin package is the NSMD (non-solder mask defined)

type.

For best results during assembly, alignment ordinals on the

PC board may be used to facilitate placement of the micro

SMD device.

LM3710/LM3711

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Timing Diagrams

20011828

FIGURE 1. LM3710/LM3711 Reset Time with MR and WDI

20011829

FIGURE 2. LLO Output

20011830

FIGURE 3. PFI Comparator Timing Diagram

LM3710/LM3711

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Typical Application Circuits

20011818

FIGURE 4. Monitoring Two Critical Supplies And Dataline

20011819

FIGURE 5. Monitoring Two Supplies plus Manual Reset And Dataline

LM3710/LM3711

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Typical Application Circuits (Continued)

20011820

FIGURE 6. Monitoring Dual Supplies plus External Fault Input And Dataline

20011821

Note: MR input with its 1.225V nominal threshold, may monitor an additional supply voltage. An internal 56 kΩpull-up resistor is

included on this input.

FIGURE 7. Microprocessor Supervisor with Early Warning Detector

LM3710/LM3711

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Typical Application Circuits (Continued)

20011840

FIGURE 8. LM3710 Long Period oscillator

LM3710/LM3711

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Physical Dimensions inches (millimeters)

unless otherwise noted

10 Lead MSOP Package

NS Package Number MUB10A

LM3710/LM3711

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

NOTES: UNLESS OTHERWISE SPECIFIED

1. EPOXY COATING

2. 63Sn/37Pb EUTECTIC BUMP

3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD.

4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE NUMBERED COUNTER

CLOCKWISE.

5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACKAGE LENGTH AND X3 IS

PACKAGE HEIGHT.

6.NO JEDEC REGISTRATION AS OF AUG.1999.

9 bump micro SMD Package

NS Package Number BPA09FFB

The dimensions of X1, X2 and X3 are given below

X1 = 1.412mm

X2 = 1.412mm

X3 = 0.850mm

LM3710/LM3711

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Notes

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves

the right at any time without notice to change said circuitry and specifications.

For the most current product information visit us at www.national.com.

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WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR

CORPORATION. As used herein:

1. Life support devices or systems are devices or systems

which, (a) are intended for surgical implant into the body, or

(b) support or sustain life, and whose failure to perform when

properly used in accordance with instructions for use

provided in the labeling, can be reasonably expected to result

in a significant injury to the user.

2. A critical component is any component of a life support

device or system whose failure to perform can be reasonably

expected to cause the failure of the life support device or

system, or to affect its safety or effectiveness.

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National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship

Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned

Substances’’ as defined in CSP-9-111S2.

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LM3710/LM3711 Microprocessor Supervisory Circuits with Power Fail Input, Low Line Output,

Manual Reset and Watchdog Timer