National Semiconductor | High-performance Analog


 LM78   

Microprocessor System Hardware Monitor [Discontinued]
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Features
  • Temperature sensing
  • 5 positive voltage inputs
  • 2 op amps for negative voltage monitoring
  • 3 fan speed monitoring inputs
  • Input for additional temperature sensors
  • Chassis Intrusion Detector input
  • WATCHDOG comparison of all monitored values
  • POST code storage RAM
  • ISA and I2C™ Serial Bus interfaces
  • Description

    The LM78 is a highly integrated Data Acquisition system for hardware monitoring of servers, Personal Computers, or virtually any microprocessor based system. In a PC, the LM78 can be used to monitor power supply voltages, temperatures, and fan speeds. Actual values for these inputs can be read at any time, and programmable WATCHDOG limits in the LM78 activate a fully programmable and maskable interrupt system with two outputs.

    The LM78 has an on-chip temperature sensor, 5 positive analog inputs, two inverting inputs (for monitoring negative voltages), and an 8-bit ADC. An input is provided for the overtemperature outputs of additional temperature sensors and this is linked to the interrupt system. The LM78 provides inputs for three fan tachometer outputs. Additional inputs are provided for Chassis Intrusion detection circuits, VID monitor inputs, and chainable interrupt. The LM78 provides both ISA and Serial Bus interfaces. A 32-byte auto-increment RAM is provided for POST (Power On Self Test) code storage.

    Key Specification
    Voltage monitoring accuracy ±1% (max)
    Temperature Accuracy -10°C to +100°C ±3°C (max)
    Supply Voltage 5V
    Supply CurrentOperating:1 mA typ
     Shutdown:10 µA typ
    ADC Resolution 8 Bits


    Applications

  • System Hardware Monitoring for Servers and PCs
  • Office Electronics
  • Electronic Test Equipment and Instrumentation
  • Also Recommended
    LM80Max Output 0-2.56V (Next Generation)
    LM81Additional DAC Output For Fan Speed Control
    LM87Additional 2 Sets Remote Diode Sensing

    Datasheets
    TitleSizeDateOther
    Language
    LM78 Microprocessor System Hardware Monitor424
    Kbytes
    26-Feb-01日本語  


    Other Technical Documents
    TitleTypeDate
    Temperature Sensors HandbookApp Note 2003-03-13

    Obsolete Versions
    Obsolete PartAlternate Part or SupplierSourceLast Time Buy Date
    LM78CCVF
    NONE
    NONE
    06 Mar 2001
    LM78CCVFX
    NONE
    NONE
    06 Mar 2001
    LM78L05ACH
    NONE
    NONE
    08 Sep 1999
    LM78L05IBP
    A78LXX
    NATIONAL SEMICONDUCTOR
    16 Nov 2008
    LM78L05IBPX
    NONE
    NATIONAL SEMICONDUCTOR
    24 Jul 2009
    LM78L09ACZ
    LM317LZ
    NATIONAL SEMICONDUCTOR
    01 Dec 2009
    LM78L09ITP
    NONE
    NATIONAL SEMICONDUCTOR
    16 Nov 2008
    LM78L12AC MWC
    NONE
    NATIONAL SEMICONDUCTOR
    03 Dec 2008
    LM78L12ACH
    NONE
    NONE
    08 Sep 1999
    LM78L15AC MDC
    NONE
    NATIONAL SEMICONDUCTOR
    03 Dec 2008
    LM78L15ACH
    NONE
    NONE
    08 Sep 1999
    LM78L82AC MDC
    NONE
    NATIONAL SEMICONDUCTOR
    03 Dec 2008
    LM78L82ACZ
    LM317LZ
    NATIONAL SEMICONDUCTOR
    01 Dec 2009
    LM78M05C MWC
    NONE
    NATIONAL SEMICONDUCTOR
    03 Dec 2008
    LM78M12CH
    LM140H-12/883
    NSCNE
    03 Dec 2008
    LM78M12CT
    LM317T
    NATIONAL SEMICONDUCTOR
    01 Dec 2009
    LM78M15CH
    LM140H-15/883
    NSCE
    03 Dec 2008
    LM78M15CT
    TA78MXX
    TOSHIBA
    16 Nov 2008
    LM78S40C MDA
    NONE
    NATIONAL SEMICONDUCTOR
    03 Dec 2008
    LM78S40J/883
    NONE
    NATIONAL SEMICONDUCTOR
    01 Dec 2009

    [Information as of 9-Feb-2012]