LP3945 Datasheet, PDF (6/15 Pages) National Semiconductor (TI) – Battery Charge Management System

Electrical Characteristics, I²C Interface (LP3945 Only) (Continued)
Unless otherwise noted, V_CHG-IN = 5V, V_BATT = 4V. Typical values and limits appearing in normal type apply for T_J = 25˚C.
Limits appearing in boldface type apply over the entire junction temperature range for operation, T_J = −40˚C to +85˚C. (Notes
6, 7, 8)
Symbol
Parameter
Conditions
Typical
Limit
Min
Max
Units
t_TRANS
Maximum Pulse Width of Spikes (Note 7)
that must be Suppressed by the
Input Filter of both DATA & CLK
50
ns
signals.
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device
is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical
Characteristics tables.
Note 2: All voltages are with respect to the potential at the GND pin.
Note 3: The Absolute Maximum power dissipation depends on the ambient temperature and can be calculated using the formula
P = (T_J — T_A)/θ_JA, (1)
where T_J is the junction temperature, T_A is the ambient temperature, and θ_JA is the junction-to-ambient thermal resistance. The 1.76W rating appearing under
Absolute Maximum Ratings results from substituting the Absolute Maximum junction temperature, 150˚C, for T_J, 85˚C for T_A, and 37˚C/W for θ_JA. More power can
be dissipated safely at ambient temperature below 85˚C. Less power can be dissipated safely at ambient temperatures above 85˚C. The Absolute Maximum power
dissipation can be increased by 27 mW for each degree below 85˚C, and it must be de-rated by 27 mW for each degree above 85˚C.
Note 4: The human-body model is 100 pF discharged through 1.5 kΩ. The machine model is 0Ω in series with 220pF
Note 5: Like the Absolute Maximum power dissipation, the maximum power dissipation for operation depends on the ambient temperature. The 1.08W rating
appearing under Operating Ratings results from substituting the maximum junction temperature for operation, 125˚C, for T_J, 85˚C for T_A, and 37˚C/W for θ_JA into
(1) above. More power can be dissipated at ambient temperatures below 85˚C. Less power can be dissipated at ambient temperatures above 85˚C. The maximum
power dissipation for operation can be increased by 27 mW for each degree below 85˚C, and it must be de-rated by 27 mW for each degree above 85˚C.
Note 6: All limits are guaranteed. All electrical characteristics having room-temperature limits are tested during production with T_J = 25˚C. All hot and cold limits are
guaranteed by correlating the electrical characteristics to process and temperature variations and applying statistical process control.
Note 7: Guaranteed by design.
Note 8: LP3945 and LP3946 are not intended as a Li-Ion battery protection device, battery used in this application should have an adequate internal protection.
20066504
The end of charge current threshold default setting is at 0.1C, this threshold can be set to 0.15 or 0.2 by the controller (see bit chart for detail).
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