sm72240mfx-4.63

Manufacturer Part Numbersm72240mfx-4.63
DescriptionSolarmagic 5-pin Microprocessor Reset Circuit
ManufacturerNational Semiconductor Corporation
sm72240mfx-4.63 datasheet
 
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SolarMagic 5-Pin Microprocessor Reset Circuit
General Description
The SM72240 microprocessor supervisory circuit monitors
the power supplies in microprocessor and digital systems. It
provides a reset to the microprocessor during power-up, pow-
er-down, brown-out conditions, and manual reset.
The SM72240 asserts a reset signal whenever the supply
decreases below the factory-programmed reset threshold.
Reset will be asserted for at least 100ms even after V
above the reset threshold.
The SM72240 has an active-low open-drain RESET output.
The SM72240 is suitable for monitoring 5V. With a low supply
current of only 6µA, the SM72240 is ideal for use in portable
equipment. The SM72240 is available in the 5-pin SOT23
package.
Typical Application Circuit
© 2011 National Semiconductor Corporation
SM72240
Features
Renewable Energy Grade
Precise monitoring of 5V supply voltages
Fully specified over temperature
−40°C to +125°C
100 ms minimum Power-On Reset pulse width, 190 ms
typical:
rises
Active-Low RESET Open Drain Output
CC
Guaranteed RESET Output valid for V
Low Supply Current, 6µA typical
Power supply transient immunity
Compatible with MAX811/812 applications
Applications
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Portable/Battery-Powered Equipment
301414
June 1, 2011
1V
CC
30141437
www.national.com

sm72240mfx-4.63 Summary of contents

  • Page 1

    ... The SM72240 has an active-low open-drain RESET output. The SM72240 is suitable for monitoring 5V. With a low supply current of only 6µA, the SM72240 is ideal for use in portable equipment. The SM72240 is available in the 5-pin SOT23 package. Typical Application Circuit © 2011 National Semiconductor Corporation SM72240 Features ■ Renewable Energy Grade ■ ...

  • Page 2

    ... MR pin goes high. May be left open. Supply Voltage (+5V, nominal) Supplied as 1000 Supplied as 3000 units, tape & reel units, tape & reel SM72240MF–4.63 SM72240MFX–4.63 SM72240MF–3.08 SM72240MFX–3. below the reset threshold voltage, CC Package Package NSC Type Top Mark ...

  • Page 3

    Block Diagram SM72240 Block Diagram 3 30141435 www.national.com ...

  • Page 4

    Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications RESET, RESET Input Current, V Pin CC Output Current, RESET, RESET Pin Electrical Characteristics Typical ...

  • Page 5

    Typical Performance Characteristics Supply Current vs V Reset Timeout vs V Normalized V vs Temperature TH Supply Current vs Temperature CC 30141403 Reset Timeout vs Temperature CC 30141404 30141416 5 30141407 30141408 V vs Current OL 30141405 www.national.com ...

  • Page 6

    Low V Characteristics CC Timing Diagram www.national.com 30141406 6 30141412 ...

  • Page 7

    Circuit Information RESET OUTPUT The reset input of a µP initializes the device into a known state. The SM72240 microprocessor voltage monitoring cir- cuit asserts a forced reset output to prevent code execution errors during power-up, power-down, and brownout condi- ...

  • Page 8

    NEGATIVE-GOING V TRANSIENTS CC The SM72240 is relatively immune to short negative-going transients or glitches Figure 2 CC pulse width a negative-going V transient can have without CC causing a reset pulse. In general, as the magnitude ...

  • Page 9

    Physical Dimensions inches (millimeters) unless otherwise noted For Ordering, refer to Ordering Information table 5-Lead SOT23-5 NS Package Number MF05A 9 www.national.com ...

  • Page 10

    ... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...