LM80 National Semiconductor, LM80 Datasheet
LM80
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LM80 Summary of contents
Page 1
... A Chassis Intrusion input is pro- vided to monitor and reset an external circuit designed to latch a chassis intrusion event. The LM80 is especially suited to interface to both linear and digital temperature sensors. The 10 mV LSB and 2.56 volt input range is ideal for accepting inputs from a linear sensor such as the LM50 ...
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... Type Digital Input This is an active low input that propagates the INT_IN signal to the INT output of the LM80 via Interrupt Mask Register 1 Bit 7 and INT enable Bit 1 of the Configuration Register. Digital I/O Serial Bus bidirectional Data. Open-drain output. Digital Input Serial Bus Clock. ...
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... P-channel power MOSFET for software power control. Digital Input An active-low input that enables NAND Tree board-level connectivity testing. Refer to Section 10.0 on NAND Tree testing. Whenever NAND Tree connectivity is enabled the LM80 is also reset to its power on state. Digital Output Master Reset driver (open drain), active low output with minimum pulse width ...
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... Specified Temperature Range 150˚C LM80CIMT-3, LM80CIMT-5 Junction to Ambient Thermal Resistance ( 2000V NS Package Number: MTC24B 125V Supply Voltage (V Ground Difference (|GND − GNDA|) V Voltage Range +3.8 V for LM80CIMT-3, +4. Conditions Interface Inactive and + = 5.75V V Interface Inactive and + = 3.8V V Shutdown Mode − ...
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... V Logical “0” Input Voltage IN(0) ALL DIGITAL INPUTS Except for BTI I Logical “1” Input Current IN(1) I Logical “0” Input Current IN(0) C Digital Input Capacitance IN (Continued +3.8 V for LM80CIMT-3, +4. MIN Conditions +25˚C T +75˚C A −10˚C T +100˚C A −25˚C T +125˚ ...
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... IN(1) I Logical “0” Input Current IN(0) C Digital Input Capacitance IN AC Electrical Characteristics The following specifications apply for +2.8 V LM80CIMT-5, unless otherwise specified. Boldface limits apply for T (Note 13) Symbol Parameter SERIAL BUS TIMING CHARACTERISTICS t SCL (Clock) Period 1 t Data In Setup Time to SCL High ...
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... Note 7: Each input and output is protected by a nominal 6.5V breakdown voltage zener diode to GND; as shown below, input voltage magnitude up to 0.3V above + V or 0.3V below GND will not damage the LM80. There are parasitic diodes that exist between the inputs and the power supply rails. Errors in the ADC conversion can occur if these diodes are forward biased by more than 50 mV example sions. ...
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... Nominal speed based on a count of 153, are programmable from 1100 to 8800 RPM. Signal conditioning circuitry is included to accommodate slow rise and fall times. The LM80 provides a number of internal registers, as de- tailed in Figure 4 . These include: Configuration Register: Provides control and configura- tion ...
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... Functional Description (Continued) 2.0 INTERFACE FIGURE 4. LM80 Register Structure 9 DS100040-7 www.national.com ...
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... Functional Description 2.1 Internal Registers of the LM80 TABLE 1. The internal registers and their corresponding internal LM80 address is as follows: Register LM80 Internal Hex Address (This is the data to be written to the Address Register) Configuration Register Interrupt Status Register 1 Interrupt Status Register 2 Interrupt Mask Register 1 ...
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... Serial Communication with a Read consisting of the Serial Bus Interface Address byte, followed by the data byte read from the LM80. The default power on Serial Bus address for the LM80 is: 0101(A2)(A1)(A0) binary, where A0-A2 reflect the state of the pins defined by the same names. ...
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... GPO I/O pins, initiates reset pulse on RST_OUT/OS pin, and provides the Reset function described in Section 3.2 . Bit 0 of the Configuration Register controls the monitoring loop of the LM80. Setting Bit 0 low stops the LM80 monitor- ing loop and puts the LM80 in shutdown mode, reducing power consumption. Serial Bus communication is possible ...
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... A typical application, such as is shown in Figure 6 , might se- lect the input voltage divider to provide 1.9V at the analog in- puts of the LM80. This is sufficiently high for good resolution of the voltage, yet leaves headroom for upward excursions from the supply of about 25%. To simplify the process of re- sistor selection, set the value of R2 first ...
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... V noise immunity. Alternatively, use a shunt reference or zener diode to clamp the input level. If fans can be powered while the power to the LM80 is off, the LM80 inputs will provide diode clamping. Limit input cur- rent to the Input Current at Any Pin specification shown in the ABSOLUTE MAXIMUM RATINGS section ...
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Functional Description (Continued) (a) Fan with Tach Pull-Up to +5V (c) Fan with Tach Pull-Up to +12V and Diode Clamp Counts are based on 2 pulses per revolution tachometer outputs. RPM Time per Revolution 4400 13.64 ms 3080 19.48 ms ...
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... Functional Description 7.0 TEMPERATURE MEASUREMENT SYSTEM The LM80 bandgap type temperature sensor and ADC per- form 9-bit or a 12-bit two’s-complement conversions of the temperature. An 8-bit digital comparator is also incorporated that compares the readings to the user-programmable Hot and Overtemperature setpoints, and Hysteresis values. ...
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... Interrupt” mode, “Default Interrupt” mode, and “Comparator Mode”. Hex The OS output of the LM80 can be programmed for “One-Time Interrupt” mode and “Comparator” mode. INT can 0 FAh be programmed for “Default Interrupt” mode and “One-Time” ...
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Functional Description www.national.com (Continued) 18 ...
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... LM80, and no clamping or other interfer- ence with the line will occur. This line can also be pulled low for at least the LM80 to reset a typical Chassis Intrusion circuit. Accomplish this reset by setting Bit 5 of Configuration Register high. The bit in the Regis- ter is self-clearing ...
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... NAND TREE TESTS A NAND tree is provided in the LM80 for Automated Test Equipment (ATE) board level connectivity testing. If the user applies a logic zero to the NTEST_IN/Reset_IN input pin, the device will be in the NAND tree test mode ...
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Functional Description (Continued) 11.0 FAN MANUFACTURERS Manufacturers of cooling fans with tachometer outputs are listed below: NMB Tech 9730 Independence Ave. Chatsworth, California 91311 818 341-3355 818 341-8207 Model Num- Frame Size ber 2408NL 2.36 in sq. X 0.79 in ...
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Functional Description 12.0 REGISTERS AND RAM 12.1 Address Register The main register is the ADDRESS Register. The bit designations are as follows: Bit Name Read/ Write 7-0 Address Read/Write Pointer Bit 7 Bit 6 Bit 12.2 ...
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Functional Description (Continued) 12.3 Configuration Register — Address 00h < > = 00001000 binary Power on default 7:0 Bit Name Read/ Write 0 Start Read/Write A one enables startup of monitoring operations, a zero puts the part in standby mode. ...
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Functional Description 12.4 Interrupt Status Register 1 — Address 01h < > = 0000 0000 binary Power on default 7:0 Bit Name Read/Write 0 IN0 Read Only A one indicates a High or Low limit has been exceeded. 1 IN1 ...
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Functional Description (Continued) 12.7 Interrupt Mask Register 2 — Address 44h < > = 0000 0000 binary Power on default 7:0 Bit Name Read/ Write 0 Hot Temperature Read/Write 1 BTI Read/Write 2 FAN1 Read/Write 3 FAN2 Read/Write 4 CI ...
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Functional Description 12.8 Fan Divisor Register/RST_OUT/OS — Address 05h < > < > Power on – 7:4 is 0101, and 3:0 Bit Name Read/Write 0 FAN1 Mode Read/Write Select 1 FAN2 Mode Read/Write Select 2-3 FAN1 RPM Read/Write Control 4-5 ...
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Functional Description (Continued) 12.10 Value RAM — Address 20h–3Fh Address A7–A0 20h IN0 reading 21h IN1 reading 22h IN2 reading 23h IN3 reading 24h IN4 reading 25h IN5 reading 26h IN6 reading 27h Temperature reading 28h FAN1 reading Note: This ...
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... Typical Application FIGURE 11. In this PC application the LM80 monitors temperature, fan speed for 2 fans, and 7 power supply voltages. It also monitors an optical chassis intrusion detector. www.national.com DS100040-19 28 ...
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... Physical Dimensions inches (millimeters) unless otherwise noted Order Number LM80CIMT-3, LM80CIMTX-3, LM80CIMTX-5 or LM80CIMT-5 LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1 ...