LM85 National Semiconductor, LM85 Datasheet - Page 6

• Manufacturer Part Number: LM85
• Description: Hardware Monitor with Integrated Fan Control
• Manufacturer: National Semiconductor

www.national.com
Symbol
SMBUS TIMING CHARACTERISTICS
f
f
t
t
t
t
t
t
t
t
t
t
t
SMB
BUF
HD_STA
SU:STA
SU:STO
HD:DAT
SU:DAT
TIMEOUT
LOW
HIGH
F
R
POR
AC Electrical Characteristics
The following specifications apply for V+ = 3.0V to 3.6V unless otherwise specified in conditions. Boldface limits apply for T
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.
Note 3: When the input voltage (V
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 1.5kΩ 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 7: Typicals are at T
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 3.64Ω 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.
= T
MIN
to T
MAX
Parameter
SMBus Operating Frequency
SMBus Free Time Between Stop And
Start Condition
Hold Time After (Repeated) Start
Condition (after this period, the first
clock is generated)
Repeated Start Condition Setup Time
Stop Condition Setup Time
Data Output Hold Time
Data Input Setup Time
Data And Clock Low Time To Reset
Of SMBus Interface Logic(Note 14)
Clock Low Period
Clock High Period
Clock/Data Fall Time
Clock/Data Rise Time
Time from Power-On-Reset to LM85
Reset and Operational
; all other limits T
A
= 25˚C and represent most likely parametric norm.
IN
) at any pin exceeds the power supplies (V
A
= 25˚C.
(Continued)
Conditions
V+
>
2.8V
IN
6
<
GND or V
IN
>
V+ ), the current at that pin should be limited to 5mA. The 20mA
(Note 7)
Typical
(Note 8)
Limits
1000
100
300
930
250
300
500
4.7
4.0
4.7
4.0
4.7
4.0
10
25
35
50
20035303
kHz (max)
kHz (min)
ms (max)
ms (max)
ns (max)
ms (min)
µs (max)
ns (max)
ns (max)
(Limits)
µs (min)
µs (min)
µs (min)
µs (min)
ns (min)
ns (min)
µs (min)
µs (min)
Units
A