LM3704XBBP-232/NOPB_技术文档

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September 2003

LM3704/LM3705

Microprocessor Supervisory Circuits with Power Fail

Input, Low Line Output and Manual Reset

n No external components required

n Manual-Reset input

The LM3704/LM3705 series of microprocessor supervisory

n RESET (LM3704) or RESET (LM3705) outputs

General Description

circuits provide the maximum flexibility for monitoring power

supplies and battery controlled functions in systems without

backup batteries. The LM3704/LM3705 series are available

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

n Precision supply voltage monitor

n Factory programmable Reset Timeout Delay

n Separate Power Fail comparator

n Available in micro SMD package for minimum footprint

Built-in features include the following:

n

0.5% Reset threshold accuracy at room temperature

2% Reset threshold accuracy over temperature

extremes

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

brownout conditions. RESET is guaranteed down to V_CCof

1.0V.

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

n 28 µA V_CCsupply current

Manual Reset Input: An input that asserts reset when pulled

low.

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

Applications

warning, or to monitor a power supply other than V_CC

.

n Embedded Controllers and Processors

n Intelligent Instruments

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 Automotive Systems

n Critical µP Power Monitoring

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.

Typical Application

10136903

DS101369

www.national.com

Connection Diagram

Top View

(looking from the coating side)

micro SMD 9 Bump Package

BPA09

MSOP-10

10136902

10136901

Pin Description

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(LM3704 only).

RESET

PFO

Reset Logic Output. RESET is the inverse of RESET (LM3705 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

A2

5

4, 6

3

GND

NC

No Connect.

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

9

NC

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

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2

Block Diagram

10136926

3

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Ordering Information

10136904

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

LM3704/LM3705

Reset

Package

Marking

Part Number

Output

Timeout

Period

micro

SMD

MSOP

LM3704XBBP-232

LM3704XBBPX-232

LM3704XBBP-463

LM3704XBBPX-463

LM3704XBMM-232

LM3704XBMMX-232

LM3704XBMM-463

LM3704XBMMX-463

LM3704XCBP-308

LM3704XCBPX-308

LM3704XCMM-263

LM3704XCMMX-263

LM3704XCMM-308

LM3704XCMMX-308

LM3704XDBP-232

LM3704XDBPX-232

LM3704XDBP-463

LM3704XDBPX-463

LM3704XDMM-220

LM3704XDMMX-220

LM3704XDMM-232

LM3704XDMMx-232

LM3704XDMM-463

LM3704XDMMX-463

LM3704YAMM-308

LM3704YAMMX-308

totem-pole

open-drain

28ms

x

%%I13

%%I27

R66B

R27B

%%I4

R79B

R35B

%%I15

%%I17

R65B

R67B

R68B

R78B

28ms

x

28ms

200ms

1600ms

1.4ms

x

1.4ms

www.national.com

4

Ordering Information (Continued)

LM3704/LM3705 (Continued)

Package

Reset

Timeout

Period

Package

Marking

Part Number

Output

micro

SMD

MSOP

LM3704YBMM-360

LM3704YBMMX-360

LM3704YCMM-232

LM3704YCMMX-232

LM3704YCMM-308

LM3704YCMMX-308

LM3705XBBP-232

LM3705XBBPX-232

LM3705XBBP-463

LM3705XBBPX-463

LM3705XBMM-232

LM3705XBMMX-232

LM3705XBMM-463

LM3705XBMMX-463

LM3705XCBP-463

LM3705XCBPX-463

LM3705XCMM-308

LM3705XCMMX-308

LM3705XDBP-232

LM3705XDBPX-232

LM3705XDBP-463

LM3705XDBPX-463

LM3705XDMM-232

LM3705XDMMX-232

LM3705XDMM-463

open-drain

totem-pole

28ms

x

R49B

R76B

R48B

%%I14

%%I33

R69B

R44B

%%I5

R36B

%%I16

%%I18

R70B

R71B

200ms

28ms

x

28ms

x

28ms

x

28ms

200ms

1600ms

x

LM3705XDMMX-463

%% 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

Manual

Reset

Power Fail

Comparator

Low

Line

Output

x

LM3704

LM3705

X, Y*

X

Customized

x

* = available upon request. Contact National

5

www.national.com

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

LM3704/LM3705 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

LM3704

LM3705

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 = A

Reset Timeout Period = B

Reset Timeout Period = C

Reset Timeout Period = D

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 (LM3705)

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 (LM3704)

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

LM3704/LM3705 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

PFI/MR

V_PFT

Parameter

Conditions

Min

Typ

Max

1.250

0.8

Units

PFI Input

1.200

1.225

V

Threshold

MR Input

Threshold

V_MRT

MR, Low

MR, High

V

2.0

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

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

7

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Typical Performance Characteristics

Supply Current vs Supply Voltage

3.3V Supply Current vs Temperature

10136911

10136915

Normalized Reset Threshold Voltage vs Temperature

Reset Timeout Period vs V_CC

10136912

10136932

Max. Transient Duration vs Reset Comparator Overdrive

(V_CC= 3.3V)

Reset Timeout Period vs Temperature

10136910

10136916

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8

Typical Performance Characteristics (Continued)

Low-Line Comparator Propagation Delay vs Temperature

10136914

9

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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.

Circuit Information

RESET OUTPUT

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

state. The LM3704/LM3705 microprocessor supervisory cir-

cuits assert a forced reset output to prevent code execution

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

tions.

The voltage threshold is set by R₁and R₂and is calculated

as follows:

>

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 LM3704 offers an active-low RESET; The

LM3705 offers an active-high RESET.

Note this comparator is completely separate from the rest of

the circuitry, and may be employed for other functions as

needed.

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.

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

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

See the Manual Reset Input section.

(typically 1.02 • V_RST) with hysteresis of 0.0032 • V_RST

.

SPECIAL PRECAUTIONS FOR THE MICRO SMD

PACKAGE

RESET THRESHOLD

The LM3704/LM3705 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.

As with most integrated circuits, the LM3704 and LM3705

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

For best results during assembly, alignment ordinals on the

PC board may be used to facilitate placement of the micro

SMD device.

www.national.com

10

Timing Diagrams

10136928

FIGURE 1. LM3704 Reset Time with MR

10136929

FIGURE 2. LLO Output

10136930

FIGURE 3. PFI Comparator Timing Diagram

11

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Typical Application Circuits

10136918

FIGURE 4. Monitoring Two Critical Supplies

10136919

FIGURE 5. Monitoring Two Supplies plus Manual Reset

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12

Typical Application Circuits (Continued)

10136920

FIGURE 6. Monitoring Dual Supplies plus External Fault Input

10136921

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

13

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Typical Application Circuits (Continued)

10136924

FIGURE 8. LM3705 Power-On Delay

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14

Typical Application Circuits (Continued)

10136923

FIGURE 9. LM3705 Power-On Delay with Overvoltage Protection

15

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Typical Application Circuits (Continued)

10136922

FIGURE 10. Regulator/Switch with Long-Term Overvoltage Lockout Prevents Overdissipation in Linear Regulator

10136931

FIGURE 11. Switch Debouncer

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16

Physical Dimensions inches (millimeters)

unless otherwise noted

10 Lead MSOP Package

NS Package Number MUB10A

17

www.national.com

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

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.

National Semiconductor

Americas Customer

Support Center

National Semiconductor

Europe Customer Support Center

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

National Semiconductor

Asia Pacific Customer

Support Center

National Semiconductor

Japan Customer Support Center

Fax: 81-3-5639-7507

Email: new.feedback@nsc.com

Tel: 1-800-272-9959

Email: europe.support@nsc.com

Deutsch Tel: +49 (0) 69 9508 6208

English Tel: +44 (0) 870 24 0 2171

Français Tel: +33 (0) 1 41 91 8790

Email: ap.support@nsc.com

Email: jpn.feedback@nsc.com

Tel: 81-3-5639-7560

www.national.com

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.


型号：	LM3704XBBP-232/NOPB
厂家：	TEXAS INSTRUMENTS
描述：	2-CHANNEL POWER SUPPLY SUPPORT CKT, PBGA9, MICRO SMD, BUMP PACKAGE, 9 PIN
文件：	总19页 (文件大小：346K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LM3704XBBP-232/NOPB [TI]

相关型号：

LM3704XBBP-308

LM3704XBBP-308

LM3704XBBP-463/NOPB

LM3704XBBP-643

LM3704XBBPX-232/NOPB

LM3704XBBPX-308

LM3704XBBPX-308

LM3704XBBPX-643

LM3704XBMM-308

LM3704XBMM-308

LM3704XBMM-643

LM3704XBMMX-232