The following specifications apply for V+ = 3.0V to 3.6V unless otherwise specified in conditions. Boldface limits apply for T

A

=T

Symbol

Parameter

Conditions

Typical

(Note 7)

Limits

(Note 8)

Units

(Limits)

SMBUS TIMING CHARACTERISTICS

f

SMB

SMBus Operating Frequency

10

100

kHz (min)

kHz (max)

f

BUF

SMBus Free Time Between Stop And

Start Condition

4.7

µs (min)

t

HD_STA

Hold Time After (Repeated) Start

Condition (after this period, the first

clock is generated)

4.0

µs (min)

t

SU:STA

Repeated Start Condition Setup Time

4.7

µs (min)

t

SU:STO

Stop Condition Setup Time

4.0

µs (min)

t

HD:DAT

Data Output Hold Time

300

ns (min)

930

ns (max)

t

SU:DAT

Data Input Setup Time

250

ns (min)

t

TIMEOUT

Data And Clock Low Time To Reset

Of SMBus Interface Logic(Note 14)

25

35

ms (min)

ms (max)

t

LOW

Clock Low Period

4.7

µs (min)

t

HIGH

Clock High Period

4.0

50

µs (min)

µs (max)

t

F

Clock/Data Fall Time

300

ns (max)

t

R

Clock/Data Rise Time

1000

ns (max)

t

POR

Time from Power-On-Reset to LM85

Reset and Operational

500

ms (max)

20035303

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 noted.

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

Note 4: Human body model, 100pF discharged through a 1.5k

Ω resistor. Machine model, 200pF discharged directly into each pin.

Note 5: Thermal resistance junction-to-ambient when attached to a printed circuit board with 2 oz. foil is 125˚C/W.

Note 6: See the URL ”http://www.national.com/packaging/“ for other recommendations and methods of soldering surface mount devices.

Note 8: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Note 9: The average current can be calculated from the peak current using the following equation:

Quiescent current will not increase substantially with an SMBus transaction.

Note 10: The accuracy of the LM85CIMQA is guaranteed when using the thermal diode of Intel Pentium 4 processors in 423 pin or 478 pin packages or any thermal

diode with a typical non-ideality factor of 1.0045. The accuracy of the LM85BIMQA is guaranteed when using the thermal diode of an Intel Pentium 4 processors or

any thermal diode with a typical non-ideality of 1.0021 and series resistance of 3.64

Ω or 3.86Ω. When using a 2N3904 type transistor as a thermal diode the error

band will be typically shifted by -1˚C.

Note 11: Local temperature accuracy does not include the effects of self-heating. The rise in temperature due to self-heating is the product of the internal power

dissipation of the LM85 and the thermal resistance. See (Note 5) for the thermal resistance to be used in the self-heating calculation.

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