LM80 datasheet(7/29 Pages) NSC

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AC Electrical Characteristics (Continued)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is

functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed

specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test

conditions.

Note 2: All voltages are measured with respect to GND, unless otherwise specified

Note 3: When the input voltage (VIN) at any pin exceeds the power supplies (VIN< (GND or GNDA) or VIN>V

+), the current at that pin should be limited to 5 mA.

The 20 mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5 mA to four.

Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax, θJA and the ambient temperature, TA. The maximum

allowable power dissipation at any temperature is PD =(TJmax−T A)/θJA.

Note 5: The human body model is a 100 pF capacitor discharged through a 1.5 k

Ω resistor into each pin. The machine model is a 200 pF capacitor discharged

directly into each pin.

Note 6: See the section titled “Surface Mount” found in any post 1986 National Semiconductor Linear Data Book for other methods of soldering surface mount

devices.

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. As an example, if V+ is 4.50 VDC, input voltage must be ≤ 4.55 VDC, to ensure accurate

conversions.

Note 8: Typicals are at TJ=TA=25˚C and represent most likely parametric norm.

Note 9: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Note 10: TUE (Total Unadjusted Error) includes Offset, Gain and Linearity errors of the ADC.

Note 11:

Total Monitoring Cycle Time includes temperature conversion, 7 analog input voltage conversions and 2 tachometer readings. Each input voltage

conversion takes 100 ms typical and 112 ms maximum. 8-plus sign Temperature resolution takes 100 ms typical and 112 ms maximum, while 11-bit plus sign takes

800 ms typical and 900 ms maximum. Fan tachometer readings take 20 ms typical, at 4400 rpm, and 200 ms max.

Note 12: The total fan count is based on 2 pulses per revolution of the fan tachometer output.

Note 13: Timing specifications are tested at the Serial Bus Input logic levels, VIN(0) = 0.3xV

+ for a falling edge and V

IN(1) =0.7xV

+ for a rising edge.

DS100040-5

An x indicates that the diode exists.

Pin Name

INT_IN

NTEST_IN/

Reset_IN

IN0-IN6

GPO

BTI

xxx

FAN1–FAN2

INT

xxx

SCL

A1-A2

SDA

A0/NTEST_Out

RST_OUT/OS

FIGURE 2. ESD Protection Input Structure

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