Datasheet

LT8640/LT8640-1
4
Rev.C
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ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LT8640E/LT8640-1E is guaranteed to meet performance
specifications from 0°C to 125°C junction temperature. Specifications
over the –40°C to 125°C operating junction temperature range are assured
by design, characterization, and correlation with statistical process
controls. The LT8640I/LT8640-1I is guaranteed over the full –40°C to
125°C operating junction temperature range. The LT8640H/LT8640-1H is
guaranteed over the full –40°C to 150°C operating junction temperature
range. High junction temperatures degrade operating lifetimes. Operating
lifetime is derated at junction temperatures greater than 125°C.
The junction temperature (T
J
, in °C) is calculated from the ambient
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.
PARAMETER CONDITIONS MIN TYP MAX UNITS
LT8640-1 Output Sink Current in Forced
Continuous Mode
V
FB
= 1.01V, L = 6.8µH, R
T
= 60.4k 0.25 0.6 1 A
LT8640-1 V
IN
to Disable Forced Continuous
Mode
V
IN
Rising 35 37 39 V
LT8640-1 V
FB
Offset from Feedback
Reference Voltage to Disable Forced
Continuous Mode
V
FB
Rising 7 9.5 12 %
temperature (T
A
in °C) and power dissipation (PD, in Watts) according to
the formula:
T
J
= T
A
+ (PD • θ
JA
)
where θ
JA
(in °C/W) is the package thermal impedance.
Note 3: θ values determined per JEDEC 51-7, 51-12. See Applications
Information section for information on improving the thermal resistance
and for actual temperature measurements of a demo board in typical
operating conditions.
Note 4: This IC includes overtemperature protection that is intended to
protect the device during overload conditions. Junction temperature will
exceed 150°C when overtemperature protection is active. Continuous
operation above the specified maximum operating junction temperature
will reduce lifetime.
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