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Low-Cost Microprocessor Supervisory Circuits with Battery Backup

Battery-Backup with Manual Reset and Power-Fail Comparator

Product Details

Key Features

Parametric specs for Battery Backup Circuits
Reset Thresh. (V) 2.5 to 3.3
3.3 to 5.5
Reset Out Active Low
Push-Pull
ICC (µA) (max) 350
Oper. Temp. (°C) -55 to +125
-40 to +85
0 to +70
Package/Pins PDIP/8
SOIC (N)/8
Budgetary
Price (See Notes)
4.45
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Simplified Block Diagram

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Parameters

Parametric specs for Battery Backup Circuits
Reset Thresh. (V) 2.5 to 3.3
3.3 to 5.5
Reset Out Active Low
Push-Pull
ICC (µA) (max) 350
Oper. Temp. (°C) -55 to +125
-40 to +85
0 to +70
Package/Pins PDIP/8
SOIC (N)/8
Budgetary
Price (See Notes)
4.45

Key Features

  • Battery-Backup Power Switching
  • Precision Supply-Voltage Monitor
    • 4.65V (MAX703)
    • 4.40V (MAX704)
  • 200ms Reset Pulse Width
  • Debounced TTL/CMOS-Compatible Manual Reset Input
  • 200µA Quiescent Current
  • 50nA Quiescent Current in Battery-Backup Mode
  • Voltage Monitor for Power-Fail or Low-Battery Warning
  • 8-Pin DIP and SO Packages
  • Guaranteed RESET-bar Assertion to VCC = 1V

Applications/Uses

  • Computers
  • Controllers
  • Critical µP Power Monitoring
  • Intelligent Instruments

Description

The MAX703/MAX704 microprocessor (µP) supervisory circuits reduce the complexity and number of components required for power-supply monitoring and battery control functions in µP systems. These devices significantly improve system reliability and accuracy compared to that obtained with separate ICs or discrete components.

The MAX703/MAX704 are available in 8-pin DIP and SO packages and provide four functions:
  1. An active-low reset during power-up, power-down, and brownout conditions.
  2. Battery-backup switching for CMOS RAM, CMOS µPs, or other low-power logic circuitry.
  3. A 1.25V threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than +5V.
  4. An active-low manual reset input.
The MAX703 and MAX704 differ only in their supply-voltage monitor levels. The MAX703 generates a reset when the supply drops below 4.65V, while the MAX704 generates a reset below 4.40V.

Simplified Block Diagram

MAX703, MAX704: Typical Operating Circuit MAX703, MAX704: 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 .