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4-Pin, µP Voltage Monitors with Pin-Selectable Power-On Reset Timeout Delay

4-Pin SOT Reset ICs with Selectable Reset Timeout Delay

Product Details

Key Features

Parametric specs for Supervisors (1 Monitored Voltage)
Reset Thresh. (V) 2.5 to 3.3
3.3 to 5.5
Reset Thresh. Accur. (%) (@ +25°C) 1.5
Reset Out Active Low
Push-Pull
tRESET (min) 15ms to 85ms
85ms to 300ms
<1ms
Adjustable
Watchdog Feature No Watchdog
ICC (µA) (max) 7
Package/Pins SOT23/4
Budgetary
Price (See Notes)
1.56
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Simplified Block Diagram

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Parameters

Parametric specs for Supervisors (1 Monitored Voltage)
Reset Thresh. (V) 2.5 to 3.3
3.3 to 5.5
Reset Thresh. Accur. (%) (@ +25°C) 1.5
Reset Out Active Low
Push-Pull
tRESET (min) 15ms to 85ms
85ms to 300ms
<1ms
Adjustable
Watchdog Feature No Watchdog
ICC (µA) (max) 7
Package/Pins SOT23/4
Budgetary
Price (See Notes)
1.56

Key Features

  • Pin-Selectable, Precision Power-On Reset Delay: 1ms (max), 20ms (min), or 100ms (min)
  • Precision Monitoring of +3V to +5V Power-Supply Voltages
  • 2.5µA Supply Current
  • Guaranteed Over Temperature (-40°C to +125°C)
  • Guaranteed Active-Low RESET Valid to VCC = 1V (MAX821)
  • Power-Supply Transient Immunity
  • No External Components
  • SOT143 Package

Applications/Uses

  • Bar-Code Scanners
  • Computers: Desktop, Workstation, Server
  • Controllers
  • Critical µP and µC Power Monitoring
  • Intelligent Instruments
  • Portable Battery-Powered Equipment

Description

The MAX821/MAX822 microprocessor (µP) supervisory circuits monitor power supplies in µP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with 5V-powered or 3V-powered circuits. The MAX821/MAX822 also provide a power-on reset timeout delay that is pin selectable to 1ms (max), 20ms (min), or 100ms (min).

These devices perform a single function: they assert a reset signal whenever the VCC supply voltage falls below a preset threshold, and they keep reset asserted for the pin-selected reset timeout delay after VCC has risen above the reset threshold. The only difference between the two devices is that the MAX821 has an active-low RESET output (which is guaranteed to be in the correct state for VCC down to 1V), while the MAX822 has an active-high RESET output. The reset comparator is designed to ignore fast transients on VCC. Reset thresholds suitable for operation with a variety of supply voltages are available.

Low supply current makes the MAX821/MAX822 ideal for use in portable equipment. These devices come in a 4-pin SOT143 package.

Simplified Block Diagram

MAX821, MAX821L, MAX821M, MAX821P, MAX821R, MAX821S, MAX821T, MAX821U, MAX822, MAX822L, MAX822M, MAX822R, MAX822S, MAX822T: Typical Operating Circuit MAX821, MAX821L, MAX821M, MAX821P, MAX821R, MAX821S, MAX821T, MAX821U, MAX822, MAX822L, MAX822M, MAX822R, MAX822S, MAX822T: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.