adm809

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a

ADM809/ADM810

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.Tel: 617/329-4700World Wide Web Site: http://www.analog.com Fax: 617/326-8703© Analog Devices, Inc., 1997

Microprocessor

Supervisory Circuit in 3-Pin SOT-23

FUNCTIONAL BLOCK DIAGRAM

V FEATURES

Superior Upgrade for MAX809/MAX810Specified Over Temperature

Low Power Consumption (17 ␮A)

Precision Voltage Monitor: +3 V, +3.3 V, +5 V Options Reset Assertion Down to 1 V V CC 140 ms min Power-On Reset

Logic Low RESET Output (ADM809)Logic High RESET Output (ADM810)APPLICATIONS

Microprocessor Systems Computers Controllers

Intelligent Instruments Automotive Systems GENERAL DESCRIPTION

The ADM809/ADM810 supervisory circuits monitor the power supply voltage in microprocessor systems. They pro-vide a reset output during power-up, power-down and

brownout conditions. On power-up, an internal timer holds reset asserted for 240 ms. This holds the microprocessor in a reset state until conditions have stabilized. The RESET output remains operational with V CC as low as 1 V. The ADM809 provides an active low reset signal (RESET ) while the ADM810 provides an active high signal (RESET) output.Six reset threshold voltage options are available suitable for monitoring a variety of supply voltages. Refer to Table I.The reset comparator features built-in glitch immunity,making it immune to fast transients on V CC .

The ADM809/ADM810 consumes only 17 µA, making it suitable for low power portable equipment. It is packaged in

a 3-pin SOT-23 package.

V Figure 1.Typical Operating Circuit

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ADM809/ADM810–SPECIFICATIONS

Parameter

Min Typ

Max Units Test Conditions/Comments

V CC Operating Voltage Range 1.0 5.5V T A = 0°C to +70°C 1.2

5.5V T A = –40°C to +105°C

Supply Current

2460µA V CC < 5.5 V, ADM8_L/M, T A = –40°C to +85°C 1750µA V CC < 3.6 V, ADM8_R/S/T, T A = –40°C to +85°C 100µA V CC < 5.5 V, ADM8_L/M, T A = +85°C to +105°C 100

µA

V CC < 3.6 V, ADM8_R/S/T, T A = +85°C to +105°C

RESET THRESHOLD Reset Voltage Threshold ADM8_L 4.56 4.63 4.70V T A = +25°C

ADM8_L 4.5 4.75V T A = –40°C to +85°C ADM8_L 4.40 4.86V T A = +85°C to +105°C ADM8_M 4.31 4.38 4.45V T A = +25°C

ADM8_M 4.25 4.5V T A = –40°

C to +85°C ADM8_M 4.16 4.56V T A = +85°C to +105°C ADM8_␣J 3.93 4.00 4.06V T A = +25°C

ADM8_ J 3. 4.10V T A = –40°C to +85°C ADM8_ J 3.80 4.20V T A = +85°C to +105°C ADM8_T 3.04 3.08 3.11V T A = +25°C

ADM8_T 3.00 3.15V T A = –40°C to +85°C ADM8_T 2.92 3.23V T A = +85°C to +105°C ADM8_S 2. 2.93 2.96V T A = +25°C

ADM8_S 2.85 3.00V T A = –40°C to +85°C ADM8_S 2.78 3.08V T A = +85°C to +105°C ADM8_R 2.59 2.63

2.66V T A = +25°C

ADM8_R 2.55 2.70V T A = –40°C to +85°C ADM8_R

2.50

2.76V T A = +85°C to +105°C Reset Threshold Temperature Coefficient 30ppm/°C V CC to Reset Delay

20

µs

V CC = V TH to (V TH –100 mV)Reset Active Timeout Period

140240

560ms T A = –40°C to +85°C 100

840ms T A = +85°C to +105°C

RESET Output Voltage Low (ADM809)

0.3V V CC = V TH min, I SINK = 1.2 mA, ADM809R/S/T 0.4V V CC = V TH min, I SINK = 3.2 mA, ADM809L/M 0.3

V V CC >1.0 V, I SINK = 50 µA

RESET Output Voltage High (ADM809)0.8 V CC V V CC > V TH max, I SOURCE = 500 µA, ADM809R/S/T V CC –1.5

V V CC > V TH max, I SOURCE = 800 µA, ADM809L/M RESET Output Voltage Low (ADM810)0.3V V CC = V TH min, I SINK = 1.2 mA, ADM810R/S/T 0.4

V V CC = V TH min, I SINK = 3.2 mA, ADM810L/M RESET Output Voltage High (ADM810)

0.8 V CC

V

1.8 V < V CC < V TH min, I SOURCE = 150 µA

(V CC = Full Operating Range, T A = T MIN to T MAX , V CC typ = 5 V for L/M/J, 3.3 V for T/S, 3 V for R Models unless otherwise noted.)

ABSOLUTE MAXIMUM RATINGS*

(T A = +25°C unless otherwise noted)

V CC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .–0.3 V to +6 V RESET , RESET . . . . . . . . . . . . . . . . . .–0.3 V to Vcc + 0.5 V Input Current

V CC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 mA Output Current

RESET , RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 mA Rate of Rise, V CC . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 V/µs

Power Dissipation, RT-3 SOT-23 . . . . . . . . . . . . . . . .320 mW Derate by 4 mW/°C above +70°C

θJA Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . .333°C/W Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . .+300°C Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . .+215°C Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . .+220°C Storage Temperature Range . . . . . . . . . . . . .–65°C to +150°C

*Stresses above those listed under Absolute Maximum Ratings may cause perma-nent damage to the device. This is a stress rating only; 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.

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily accumulate on the human body and test equipment and can discharge without detection.Although the ADM809/ADM810 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

ADM809/ADM810

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PIN FUNCTION DESCRIPTION

Pin Mnemonic Function

1GND

0 V. Ground reference for all signals.

2

RESET (ADM809)Active Low Logic Output. RESET

remains low while V CC is below the reset threshold, and remains low for 240 ms (typ) after V CC rises above the reset threshold 2

RESET (ADM810)Active High Logic Output. RESET

remains high while V CC is below the reset threshold, and remains high for 240 ms (typ) after V CC rises above the reset threshold.

3

V CC

Supply voltage being monitored.

PIN CONFIGURATION

GND RESET , RESET CC

V t1 = RESET TIME = 240ms TYP.

V REF = RESET VOLTAGE THRESHOLD

Figure 2.Power Fail Reset Timing Table I.Reset Threshold Options

RESET Model

Threshold ADM809LART 4.63 V ADM809MART 4.38 V ADM809JART 4.00 V ADM809TART 3.08 V ADM809SART 2.93 V ADM809RART 2.63 V ADM810LART 4.63 V ADM810MART 4.38 V ADM810JART 4.00 V ADM810TART 3.08 V ADM810SART 2.93 V ADM810RART

2.63 V

ORDERING GUIDE

Reset

Temperature Brand

Model*

Threshold Range

Information Quantity ADM809LART-REEL 4.63 V –40°C to +105°C 9LXX 10K ADM809LART-REEL-7 4.63 V –40°C to +105°C 9LXX 3K ADM809MART-REEL 4.38 V –40°C to +105°C 9MXX 10K ADM809MART-REEL-7 4.38 V –40°C to +105°C 9MXX 3K ADM809JART-REEL 4.00 V –40°C to +105°C 9JXX 10K ADM809JART-REEL-7 4.00 V –40°C to +105°C 9JXX 3K ADM809TART-REEL 3.08 V –40°C to +105°C 9TXX 10K ADM809TART-REEL-7 3.08 V –40°C to +105°C 9TXX 3K ADM809SART-REEL 2.93 V –40°C to +105°C 9SXX 10K ADM809SART-REEL-7 2.93 V –40°C to +105°C 9SXX 3K ADM809RART-REEL 2.63 V –40°C to +105°C 9RXX 10K ADM809RART-REEL-7 2.63 V –40°C to +105°C 9RXX 3K ADM810LART-REEL 4.63 V –40°C to +105°C ALXX 10K ADM810LART-REEL-7 4.63 V –40°C to +105°C ALXX 3K ADM810MART-REEL 4.38 V –40°C to +105°C AMXX 10K ADM810MART-REEL-7 4.38 V –40°C to +105°C AMXX 3K ADM810JART-REEL 4.00 V –40°C to +105°C AJXX 10K ADM810JART-REEL-7 4.00 V –40°C to +105°C AJXX 3K ADM810TART-REEL 3.08 V –40°C to +105°C ATXX 10K ADM810TART-REEL-7 3.08 V –40°C to +105°C ATXX 3K ADM810SART-REEL 2.93 V –40°C to +105°C ASXX 10K ADM810SART-REEL-7 2.93 V –40°C to +105°C ASXX 3K ADM810RART-REEL 2.63 V –40°C to +105°C ARXX 10K ADM810RART-REEL-7

2.63 V

–40°C to +105°C

ARXX

3K

*Only available in Reels.

ADM809/ADM810–4–

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TEMPERATURE –

C

235–40

–20

20

40

60

80235.5236236.5237237.5238238.5239239.524085

Figure 6.Power-Down RESET Delay vs. Temperature ADM8_R

—Typical Performance Characteristics

TEMPERATURE – C

0.999

–40

–2002040

60801.0021.00151.0011.0005

1.0

0.999585

Figure 7.Normalized RESET Voltage Threshold vs. Temperature

RESET COMPARATOR OVERDRIVE, V TH – V CC (mV)

Figure 9.Maximum Transient Dura-tion Without Causing a RESET Pulse vs. RESET Comparator Overdrive

TEMPERATURE –

ADM809/ADM810

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INTERFACING TO OTHER DEVICES OUTPUT

The ADM809/ADM810 Series is designed to integrate with as many devices as possible and therefore has a standard output dependant on V CC . This enables the part to be used in both 3 V and 5 V or any nominal voltage within the minimum and maxi-mum specifications for V CC . Because of this design approach,interfacing this device to other devices is simplified.

ENSURING A VALID RESET OUTPUT DOWN TO V CC = 0 V

When V CC falls below 0.8 V, ADM809’s RESET no longer sinks current. A high impedance CMOS logic input connected to RESET may, therefore, drift to undetermined logic levels. To eliminate this problem a 100 k Ω resistor should be connected from RESET to ground.

V

Figure 10.Ensuring a Valid RESET Output Down to V CC = 0 V

THE BENEFITS OF A VERY ACCURATE RESET THRESHOLD

In other microprocessor supervisory circuits, tolerances in sup-ply voltages lead to an overall increase in RESET tolerance levels due to the deterioration of the microprocessor RESET circuit’s power supply. The possibility of a malfunction during a power failure is greatly reduced because the ADM809 and ADM810 series can operate effectively even when there are large degradations of the supply voltages. Another advantage of the ADM809 and ADM810 series is its very accurate internal voltage reference circuit. These benefits combine to produce an exceptionally reliable Voltage Monitor Circuit.

INTERFACING TO MICROPROCESSORS WITH MULTIPLE INTERRUPTS

In a number of cases it is necessary to interface many interrupts from different devices (i.e., thermal, attitude and velocity sen-sors). The ADM809 and ADM810 can easily be integrated into existing interrupt-handling circuits (Figure 11) or used as a stand-alone device.

Figure 11.Interfacing to µPs with Multiple Interrupts

ADM809/ADM810

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OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

C 3047–12–4/97

P R I N T E D I N U .S .A .

Surface Mount Package

RT-3