Rainbow Electronics LM85 - Manual (Page 6)

AC Electrical Characteristics
(Continued)
The following specifications apply for V+ = 3.0V to 3.6V unless otherwise specified in conditions. Boldface limits apply for T
A
= T
MIN
to T
MAX
; all other limits T
A
= 25˚C.
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
V+ > 2.8V 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.
Note 3: When the input voltage (V
IN
) at any pin exceeds the power supplies (V
IN
< GND or V
IN
> V+ ), the current at that pin should be limited to 5mA. The 20mA
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 7: Typicals are at T
A
= 25˚C and represent most likely parametric norm.
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.
LM85
www.national.com 6