Datasheet

LT3652
4
3652fd
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
TIMER
Full Charge Cycle Timeout 3 hr
Precondition Timeout 22.5 min
Timer Accuracy
l
–10 10 %
f
O
Operating Frequency 1MHz
DC Duty Cycle Range Continuous Operation
l
15 90 %
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 20V, Boost – SW = 4V, SHDN = 2V, V
FB
= 3.3V, C
TIMER
= 0.68μF.
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 LT3652EDD is guaranteed to meet performance specifi cations
from 0°C to 125°C junction temperature. Specifi cations over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization, and correlation with statistical process controls. The
LT3652IDD specifi cations are guaranteed over the full –40°C to 125°C
operating junction temperature range. High junction temperatures degrade
operating lifetimes.
Note 3: V
IN
minimum voltages below the start threshold are only
supported if (V
BOOST
-V
SW
) > 2V.
Note 4: This parameter is valid for programmed output battery fl oat
voltages ≤ 4.2V. V
IN
operating range minimum is 0.75V above the
programmed output battery fl oat voltage (V
BAT(FLT)
+ 0.75V). V
IN
Start
Voltage is 3.3V above the programmed output battery fl oat voltage
(V
BAT(FLT)
+ 3.3V).
Note 5: Output battery fl oat voltage (V
BAT(FLT)
) programming resistor
divider equivalent resistance = 250k compensates for input bias current.
Note 6: All V
FB
voltages measured through 250k series resistance.
Note 7: V
SENSE(DC)
is reduced by thermal foldback as junction temperature
approaches 125°C.