LM80 datasheet(6/35 Pages) TI1

6 / 35 page

LM80

SNIS102F – JUNE 1999 – REVISED MARCH 2013

www.ti.com

DC Electrical Characteristics

The following specifications apply for +2.8 VDC ≤V

+ ≤ +3.8 V

DC for LM80CIMT-3, +4.25 VDC ≤V

+ ≤ +5.75 V

DC for LM80CIMT-5,

IN0-IN6 RS = 25Ω, unless otherwise specified. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ =

25°C.

(1)

Units

Symbol

Parameter

Conditions

Typical(2)

Limits(3)

(Limits)

POWER SUPPLY CHARACTERISTICS

I+

Supply Current

Interface Inactive and V+= 5.75V

0.2

2.0

mA (max)

Interface Inactive and V+= 3.8V

0.18

1.5

mA (max)

Shutdown Mode

μA

TEMPERATURE-to-DIGITAL CONVERTER CHARACTERISTICS

Temperature Error

−25°C ≤ TA ≤ +125°C

±3

°C (max)

Resolution

0.5

°C (min)

ANALOG-to-DIGITAL CONVERTER CHARACTERISTICS

Resolution (8 bits with full-scale at 2.56V)

TUE

Total Unadjusted Error

See(4)

±1

% (max)

DNL

Differential Non-Linearity

±1

LSB (max)

PSS

Power Supply Sensitivity

±1

%/V

Total Monitoring Cycle Time

See(5)

9-bit Temp resolution

1.0

1.5

sec (max)

12-bit Temp resolution

sec (max)

MULTIPLEXER/ADC INPUT CHARACTERISTICS

On Resistance

0.5

Ω (max)

Input Current (On Channel Leakage Current)

±1

μA

Off Channel Leakage Current

±1

μA

FAN RPM-to-DIGITAL CONVERTER

Fan RPM Error

+25°C

≤ TA ≤ +75°C

±10

% (max)

−10°C ≤ TA ≤ +100°C

±15

% (max)

−25°C ≤ TA ≤ +125°C

±20

% (max)

Full-scale Count

255

(max)

FAN1 and FAN2 Nominal Input

Divisor = 1, Fan Count = 153(6)

8800

RPM

RPM (See FAN INPUTS)

Divisor = 2, Fan Count = 153(6)

4400

RPM

Divisor = 3, Fan Count = 153(6)

2200

RPM

Divisor = 4, Fan Count = 153(6)

1100

RPM

Internal Clock Frequency

+25°C

≤ TA ≤ +75°C

20.2

kHz (min)

22.5

24.8

kHz (max)

19.1

kHz (min)

−10°C ≤ TA ≤ +100°C

22.5

25.9

kHz (max)

kHz (min)

−25°C ≤ TA ≤ +125°C

22.5

kHz (max)

(1)

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.

(2)

Typicals are at TJ=TA=25°C and represent most likely parametric norm.

(3)

Limits are specified to AOQL (Average Outgoing Quality Level).

(4)

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

(5)

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.

(6)

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

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