LM3710XKMMX-463_技术文档

January 2005

LM3710/LM3711

Microprocessor Supervisory Circuits with Power Fail

Input, Low Line Output, Manual Reset and Watchdog

Timer

General Description

Features

n Standard Reset Threshold voltage: 3.08V

n Custom Reset Threshold voltages: For other voltages

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

National Semiconductor Corp.

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.

n No external components required

Built-in features include the following:

n Manual-Reset input

n RESET (LM3710) or RESET (LM3711) outputs

n Precision supply voltage monitor

n Factory programmable Reset and Watchdog Timeout

Delays

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

brownout conditions. RESET is guaranteed down to V_CCof

1.0V.

Manual Reset Input: An input that asserts reset when pulled

low.

n Separate Power Fail comparator

n Available in micro SMD package for minimum footprint

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

warning, or to monitor a power supply other than V_CC

.

n

0.5% Reset threshold accuracy at room temperature

2% Reset threshold accuracy over temperature

extremes

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.

n Reset assertion down to 1V V_CC(RESET option only)

n 28 µA V_CCsupply current

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.

Applications

n Embedded Controllers and Processors

n Intelligent Instruments

n Automotive Systems

n Critical µP Power Monitoring

Typical Application

20011803

DS200118

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Connection Diagram

Top View

(looking from the coating side)

micro SMD 9 Bump Package

BPA09

MSOP-10

20011802

20011801

Pin Descriptions

Pin No.

Name

Function

micro

SMD

A1

MSOP

2

MR

Manual-Reset input. When MR is less than V_MRT(Manual Reset Threshold)

RESET/RESET is engaged.

B1

C1

1

V_CC

Power Supply input.

10

RESET

Reset Logic Output. Pulses low for t_RP(Reset Timeout Period) when triggered, and stays

low whenever V_CCis below the reset threshold or when MR is below V_MRT. It remains low

for t_RPafter either V_CCrises above the reset threshold, or after MR input rises above

V_MRT(LM3710 only).

RESET

PFO

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

Power-Fail Logic Output. When PFI is below V_PFT, PFO goes low; otherwise, PFO

remains high.

C2

C3

8

7

LLO

Low-Line Logic Output. Early Power-Fail warning output. Low when V_CCfalls 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.

Ground reference for all signals.

B3

A3

5

4

GND

WDI

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

t_WD(Watchdog Timeout Period), reset is engaged.

A2

B2

3

PFI

NC

Power-Fail Comparator Input. When PFI is less than V_PFT(Power-Fail Reset Threshold),

the PFO goes low; otherwise, PFO remains high.

6, 9

No Connect. Test input used at factory only. Leave floating.

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2

Block Diagram

20011805

3

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Ordering Information

20011804

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

LM3710/LM3711

Package

Reset

Timeout

Period

Watchdog

Timeout

Period

Package

Marking

Part Number

Output

micro

MSOP

SMD

LM3710XKBP-232

LM3710XKBPX-232

LM3710XKBP-463

LM3710XKBPX-463

LM3710XKMM-232

LM3710XKMMX-232

LM3710XKMM-463

LM3710XKMMX-463

LM3710XNMM-450

LM3710XNMMX-450

LM3710XNMM-470

LM3710XNMMX-470

LM3710XQBP-308

LM3710XQBPX-308

LM3710YQMM-232

LM3710YQMMX-232

LM3711XKBP-232

LM3711XKBPX-232

LM3711XKBP-463

LM3711XKBPX-463

LM3711XKMM-232

LM3711XKMMX-232

LM3711XKMM-463

LM3711XKMMX-463

LM3710XQMM-308

totem-pole

open-drain

totem-pole

28ms

1.4ms

200ms

28ms

200ms

102ms

1600ms

102ms

1600ms

x

%%I19

%%I21

R72B

R74B

R84B

R83B

%%IA

R77B

%%I20

%%I22

R73B

R75B

R37B

x

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4

Ordering Information (Continued)

LM3710/LM3711 (Continued)

Package

Reset

Timeout

Period

Watchdog

Timeout

Period

Package

Marking

Part Number

Output

micro

MSOP

SMD

LM3710XQMMX-308

LM3711XQBP-308

LM3711XQBPX-308

LM3711XQMM-308

LM3711XQMMX-308

totem-pole

200ms

1600ms

x

R37B

%%IB

R38B

x

%% is the datecode and will vary with time.

Table Of Functions

Part

Number

Active

Low

Reset

x

Active

High

Reset

Output

(X = totem-pole)

(Y = open-drain)

Reset

Timeout

Period

Watchdog

Timeout

Period

Manual

Reset

Power Fail

Comparator

Low

Line

Output

x

LM3710

LM3711

X, Y*

X

Customized

x

* = available upon request. Contact National

5

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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.

Power Dissipation

(Note 3)

Operating Ratings (Note 1)

Temperature Range

−40˚C ≤ T_J≤ 85˚C

Supply Voltage (V_CC

All Other Inputs

)

−0.3V to 6.0V

−0.3V to V_CC+ 0.3V

ESD Ratings (Note 2)

Human Body Model

Machine Model

1.5kV

150V

LM3710/LM3711 Series Electrical Characteristics

Limits in the standard typeface are for T_J= 25˚C and limits in boldface type apply over full operating range. Unless otherwise

specified: V_CC= +2.2V to 5.5V.

Symbol

POWER SUPPLY

V_CCOperating Voltage

Parameter

Conditions

Min

Typ

Max

Units

LM3710

LM3711

1.0

1.2

5.5

50

V

Range: V_CC

I_CC

V_CCSupply

Current

All inputs = V_CC; all outputs floating

28

µA

RESET THRESHOLD

V_RST

Reset Threshold

V_CCfalling

−0.5

−2

+0.5

+2

V_RST

%

V_CCfalling: T_A= 0˚C to 70˚C

−1.5

+1.5

V_RSTH

t_RP

Reset Threshold

Hysteresis

0.0032•V_RST

mV

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

V_CCfalling at 1mV/µs

1

20

140

1120

1.4

28

2

40

280

2240

ms

µs

200

1600

20

t_RD

V_CCto Reset

Delay

RESET (LM3711)

V_OLRESET

>

V_CC2.25V, I_SINK= 900µA

0.3

0.4

>

V_CC2.7V, I_SINK= 1.2mA

V

>

V_CC4.5V, I_SINK= 3.2mA

>

V_OH

RESET

V_CC1.2V, I_SOURCE= 50µA

0.8 V_CC

>

V_CC1.8V, I_SOURCE= 150µA

>

V_CC2.25V, I_SOURCE= 300µA

0.8 V_CC

V

>

V_CC2.7V, I_SOURCE= 500µA

0.8 V_CC

>

V_CC4.5V, I_SOURCE= 800µA

V_CC− 1.5V

I_LKG

Output Leakage

Current

V_RESET= 5.5V

1.0

µA

RESET (LM3710)

V_OLRESET

>

V_CC1.0V, I_SINK= 50µA

0.3

0.4

>

V_CC1.2V, I_SINK= 100µA

>

V_CC2.25V, I_SINK= 900µA

>

V_CC2.7V, I_SINK= 1.2mA

V

>

V_CC4.5V, I_SINK= 3.2mA

>

V_OH

RESET

V_CC2.25V, I_SOURCE= 300µA

0.8 V_CC

>

V_CC2.7V, I_SOURCE= 500µA

>

V_CC4.5V, I_SOURCE= 800µA

V_CC− 1.5V

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6

LM3710/LM3711 Series Electrical Characteristics (Continued)

Limits in the standard typeface are for T_J= 25˚C and limits in boldface type apply over full operating range. Unless otherwise

specified: V_CC= +2.2V to 5.5V.

Symbol

WDI

Parameter

Conditions

Min

−1

Typ

Max

+1

Units

WDI

Watchdog Input

Current

µA

WDI_T

t_WD

Watchdog Input

Threshold

0.2•V_CC

1.225

0.8•V_CC

V

Watchdog

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

71

1120

17900

6.2

102

9.3

153

2400

38400

Timeout Period

ms

1600

25600

PFI/MR

V_PFT

PFI Input

Threshold

MR Input

Threshold

1.200

2.0

1.225

1.250

0.8

V

V_MRT

MR, Low

V

MR, High

V_PFTH

V_MRTH

I_PFI

/

PFI/MR Threshold

Hysteresis

PFI/MR falling: V_CC= V_{RST MAX}to 5.5V

0.0032•V_RST

mV

Input Current

(PFI only)

−75

35

75

nA

kΩ

µS

R_MR

t_MD

MR Pull-up

Resistance

MR to Reset

Delay

56

12

t_MR

PFO, LLO

V_OL

MR Pulse Width

25

>

PFO, LLO Output

Voltage

V_CC2.25V, I_SINK= 900µA

0.3

0.4

>

V_CC2.7V, I_SINK= 1.2mA

>

V_CC4.5V, I_SINK= 3.2mA

V

>

V_OH

V_CC2.25V, I_SOURCE= 300µA

0.8 V_CC

>

V_CC2.7V, I_SOURCE= 500µA

>

V_CC4.5V, I_SOURCE= 800µA

V_CC− 1.5V

LLO OUTPUT

V_LLOT

LLO Output

1.01•V_RST

1.02•V_RST

1.03•V_RST

Threshold

(V_LLO− V_RST, V_CC

falling)

V_LLOTH

Low-Line

0.0032•V_RST

mV

µs

Comparator

Hysteresis

t_CD

Low-Line

V_CCfalling at 1mV/µs

20

Comparator Delay

7

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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 kΩ resistor 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, T (MAX), the junction-to-ambient thermal resistance, θ

,

J-A

J

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

A

Where the value of θ

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

J-A

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Typical Performance Characteristics

Supply Current vs Supply Voltage

3.3V Supply Current vs Temperature

20011811

20011815

Normalized Reset Threshold Voltage vs Temperature

Reset Timeout Period vs V_CC

20011812

20011832

Max. Transient Duration vs Reset Comparator Overdrive

(V_CC= 3.3V)

Reset Timeout Period vs Temperature

20011810

20011816

9

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Typical Performance Characteristics (Continued)

Watchdog Timeout Period vs Temperature

(t_WDprogrammed as 6.2ms)

Low-Line Comparator Propagation Delay vs Temperature

20011814

20011813

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10

The voltage threshold is set by R₁and R₂and is calculated

as follows:

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.

Note this comparator is completely separate from the rest of

the circuitry, and may be employed for other functions as

needed.

>

RESET is guaranteed valid for V_CC

1V. Once V_CCex-

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.

LOW-LINE OUTPUT (LLO)

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

non-maskable interrupt to a µP when V_CCbegins falling. LLO

monitors V_CCand goes low when V_CCfalls below V_LLOT

Any time V_CCdrops below the reset threshold (such as

during a brownout), the reset activates. When V_CCagain

rises above the reset threshold, the internal timer starts.

Reset holds until V_CCexceeds the reset threshold for longer

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

(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.

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.

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.

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 kΩ pull-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.

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.

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_PFTseveral milliseconds

before the main supply voltage drops below the reset thresh-

old, providing advanced warning of a brownout.

For best results during assembly, alignment ordinals on the

PC board may be used to facilitate placement of the micro

SMD device.

11

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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

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12

Typical Application Circuits

20011818

FIGURE 4. Monitoring Two Critical Supplies And Dataline

20011819

FIGURE 5. Monitoring Two Supplies plus Manual Reset And Dataline

13

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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 kΩ pull-up resistor is

included on this input.

FIGURE 7. Microprocessor Supervisor with Early Warning Detector

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14

Typical Application Circuits (Continued)

20011840

FIGURE 8. LM3710 Long Period oscillator

15

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Physical Dimensions inches (millimeters)

unless otherwise noted

10 Lead MSOP Package

NS Package Number MUB10A

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16

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

17

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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.

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS

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.

BANNED SUBSTANCE COMPLIANCE

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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Americas Customer

Support Center

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Fax: +49 (0) 180-530 85 86

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Support Center

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Fax: 81-3-5639-7507

Email: new.feedback@nsc.com

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型号：	LM3710XKMMX-463
厂家：	National Semiconductor
描述：	IC 2-CHANNEL POWER SUPPLY MANAGEMENT CKT, PDSO10, MSOP-10, Power Management Circuit 光电二极管
文件：	总18页 (文件大小：695K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LM3710XKMMX-463 [NSC]

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