ADM709TAR [ADI]

Power Supply Monitor with Reset; 电源监控与复位


型号：	ADM709TAR
厂家：	ADI
描述：	Power Supply Monitor with Reset 电源监控与复位监控
文件：	总4页 (文件大小：227K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

Power Supply Monitor

with Reset

ADM709

FEATURES

FUNCTIONAL BLOCK DIAGRAM

Precision Supply Voltage Monitor

+5 V, +3.3 V, +3 V Power Supply Monitor

35 ␮A Quiescent Current

140 ms (min) Power-On Reset Pulse

Low Cost

ADM709

RESET

GENERATOR

8-Pin DIP/SO Packages

Upgrade for MAX709

GND

APPLICATIONS

Microprocessor Systems

Computers

Controllers

Intelligent Instruments

Critical ␮P Monitoring

Automotive Systems

Critical ␮P Power Monitoring

ADM709

µP

RESET

GND

GENERAL DESCRIPTION

Typical Operating Circuit

The ADM709 contains a power supply monitor which generates

a system reset during power-up, power-down and brownout

conditions. When V_CCfalls below the reset threshold, RESET

goes low and holds the µP in reset. On power-up the RESET

output is held low for 140 ms after V_CCrises above the thresh-

old. The RESET output remains operational with V_CCas low

as 1 V.

ORDERING GUIDE

Reset

Threshold

Temperature

Range

Package

Option*

Model

ADM709LAN

ADM709LAR

ADM709MAN

ADM709MAR

ADM709TAN

ADM709TAR

ADM709SAN

ADM709SAR

ADM709RAN

ADM709RAR

4.65 V

4.40 V

3.08 V

2.93 V

2.63 V

–40°C to +85°C N-8

–40°C to +85°C SO-8

–40°C to +85°C N-8

–40°C to +85°C SO-8

–40°C to +85°C N-8

–40°C to +85°C SO-8

–40°C to +85°C N-8

–40°C to +85°C SO-8

–40°C to +85°C N-8

–40°C to +85°C SO-8

Three supply-voltage threshold levels are available suitable for

+5 V, +3.3 V and for +3 V supply monitoring. The actual reset

voltage threshold is given below.

The ADM709 is available in 8-pin DIP and SOIC packages.

Table I. Reset Threshold

Suffix

Voltage (V)

4.65

4.40

3.08

2.93

2.63

*N = Plastic DIP; SO = SOIC.

REV. 0

Information furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.

Tel: 617/329-4700 Fax: 617/326-8703

(V_CC= Full Operating Range, T_A= T_MINto T_MAXunless otherwise noted)

ADM709–SPECIFICATIONS

Parameter

_CCOperating Voltage Range

Min

Typ

Max

Units Test Conditions/Comments

1.0

1.2

5.5

110

150

200

µA

T_A= 0°C to +70°C

T_A= –40°C to +85°C

Supply Current

V_CC< 3.6 V, T_A= 0°C to +70°C

V_CC< 3.6 V, T_A= –40°C to +85°C

V_CC< 5.5 V, T_A= 0°C to +70°C

V_CC< 5.5 V, T_A= –40°C to +85°C

Reset Threshold

4.5

4.65

4.40

3.08

2.93

2.63

4.75

4.50

3.15

3.00

2.70

ADM709L

ADM709M

ADM709T

ADM709S

ADM709R

4.25

3.00

2.85

2.55

V_CCto RESET Delay

µs

V_CC= Reset Threshold max–min

RESET Active Time-Out Period

RESET Output Voltage

140

280

380

0.3

V_CC= Reset Threshold max, V_CCRising

ADM709R/S/T, I_SINK= 1.2 mA. V_CC= Reset

Threshold min

0.4

ADM709L/M, I_SINK= 3.2 mA. V_CC= Reset

Threshold min

0.3

0.4

_SINK= 50 µA. V_CC≥ 1.0 V

_SINK= 100 µA. V_CC≥ 1.2 V

0.8 × V_CC

ADM709R/S/T, I_SOURCE= 500 µA, V_CC≥ Reset

Threshold max

_CC–1.5 V

ADM709L/M, I_SOURCE= 800 µA, V_CC≥ Reset

Threshold max

Specifications subject to change without notice.

PIN FUNCTION DESCRIPTION

ABSOLUTE MAXIMUM RATINGS*

(T_A= +25°C unless otherwise noted)

Mnemonic Pin No.

Function

V_CC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +6 V

RESET Output . . . . . . . . . . . . . . . . . . . –0.3 V to V_CC+ 0.3 V

V_CCInput Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mA

RESET Output Current . . . . . . . . . . . . . . . . . . . . . . . . 20 mA

Power Dissipation, N-8 DIP . . . . . . . . . . . . . . . . . . . . 727 mW

θ_JAThermal Impedance . . . . . . . . . . . . . . . . . . . . . 135°C/W

Power Dissipation, SO-8 SOIC . . . . . . . . . . . . . . . . . . 470 mW

θ_JAThermal Impedance . . . . . . . . . . . . . . . . . . . . . 110°C/W

Operating Temperature Range

Industrial ( A Version) . . . . . . . . . . . . . . . . . –40°C to +85°C

Lead Temperature (Soldering, 10 secs) . . . . . . . . . . . . +300°C

Vapor Phase (60 secs) . . . . . . . . . . . . . . . . . . . . . . . . . +215°C

Infrared (15 secs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +220°C

Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C

ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .>5 kV

V_CC

1, 4, 5, 6, 8

No Connect Pins.

+5 V, +3.3 V, +3 V Power Supply

Input.

RESET

Logic Output. It remains low while

V_CCis below the reset threshold

voltage and for 280 ms (typ) after

V_CCrises above the threshold.

GND

Ground, 0 V.

PIN CONFIGURATION

^*Stresses above those listed under “Absolute Maximum Ratings” may cause

permanent damage to the device. This is a stress rating only and functional

operation of the device at these or any other conditions above those listed in the

operational sections of this specification is not implied. Exposure to absolute

maximum ratings for extended periods of time may affect device reliability.

RESET

ADM709

GND

TOP VIEW

(Not to Scale)

NC = NO CONNECT

–2–

REV. 0

ADM709

RESET at Voltages < 1 V

ADM709

The ADM709 RESET output is guaranteed to operate with

supply voltages as low as 1 V. If it is desired that the RESET

output remains low below 1 V, then a pull-down resistor should

be connected between the RESET output and GND. A resistor

of 100 kΩ is suitable. This is illustrated in Figure 5.

RESET

GENERATOR

RESET

GND

Figure 1. Functional Block Diagram

ADM709

RESET

GND

ADM709

µP

RESET

Figure 5. RESET Valid @ V_CC< 1 V

GND

Glitch Immunity

The ADM709 is immune to short transients which may occur

on the V_CCline. This is important so that spurious resets are not

generated as a result of minor glitches on the power supply.

Figure 2. Typical Operating Circuit

CIRCUIT INFORMATION

Additional glitch immunity may be obtained by connecting a

capacitor (0.1 µF or greater) as close as possible to the V_CCpin

on the device.

RESET Output

RESET is an active low output which provides a reset signal to

the microprocessor whenever the V_CCsupply voltage is below

the reset threshold. An internal timer holds RESET low for

140 ms after the voltage on V_CCrises above the threshold. This

is intended as a power-on reset signal for the processor. It allows

time for the power supply and microprocessor to stabilize after

power up. Similarly a power supply brownout will initiate a pro-

cessor reset. On power-down, the RESET output remains low

with V_CCas low as 1 V. This ensures that the microprocessor is

held in a stable shutdown condition as the power supply drops.

Microprocessors with Bidirectional I-O

Some microprocessors or microcontrollers such as the

MC68HC11 have bidirectional reset lines. In order to avoid

signal contention, a resistor of 4.7 kΩ should be connected

between the ADM709 RESET output and the microcontroller

RESET line. This arrangement is shown in Figure 6.

BUFFERED

+5V

RESET

VRT

µP

ADM709

t_RS

RESET

GND

Figure 3. Power Off/On RESET Timing

Figure 6. Interfacing to Microprocessors with

Bidirectional RESET

RESET

400ms/DIV

Figure 4. RESET Output vs. V_CC

REV. 0

–3–

ADM709

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

8-Lead Plastic DIP

(N-8)

0.280 (7.11)

0.240 (6.10)

PIN 1

0.325 (8.25)

0.300 (7.62)

0.430 (10.92)

0.348 (8.84)

0.060 (1.52)

0.015 (0.38)

0.195 (4.95)

0.115 (2.93)

0.210

(5.33)

MAX

0.130

(3.30)

MIN

0.015 (0.381)

0.008 (0.204)

0.160 (4.06)

0.115 (2.93)

SEATING

PLANE

0.100

(2.54)

0.070 (1.77)

0.045 (1.15)

0.022 (0.558)

0.014 (0.356)

BSC

8-Lead SOIC

(SO-8)

0.1574 (4.00)

0.1497 (3.80)

PIN 1

0.2440 (6.20)

0.2284 (5.80)

0.1968 (5.00)

0.1890 (4.80)

0.0196 (0.50)

x 45

0.0099 (0.25)

0.0688 (1.75)

0.0532 (1.35)

0.0098 (0.25)

0.0040 (0.10)

0.0500 (1.27)

0.0160 (0.41)

0.0500 0.0192 (0.49)

0.0098 (0.25)

0.0075 (0.19)

(1.27)

0.0138 (0.35)

BSC

–4–

REV. 0

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