Datasheet

LTC3862
4
3862fc
For more information www.linear.com/LTC3862
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
f
SYNC
SYNC Minimum Input Frequency V
SYNC
= External Clock
l
50 kHz
SYNC Maximum Input Frequency V
SYNC
= External Clock
l
650 kHz
V
SYNC
SYNC Input Threshold Rising Threshold 1.5 V
I
PLLFLTR
Phase Detector Sourcing Output Current f
SYNC
> f
OSC
–15 µA
Phase Detector Sinking Output Current f
SYNC
< f
OSC
15 µA
CH1-CH2 Channel 1 to Channel 2 Phase Relationship V
PHASEMODE
= 0V
V
PHASEMODE
= Float
V
PHASEMODE
= 3V8
180
180
120
Deg
Deg
Deg
CH1-CLKOUT Channel 1 to CLKOUT Phase Relationship V
PHASEMODE
= 0V
V
PHASEMODE
= Float
V
PHASEMODE
= 3V8
90
60
240
Deg
Deg
Deg
D
MAX
Maximum Duty Cycle V
DMAX
= 0V (Note 9)
V
DMAX
= Float
V
DMAX
= 3V8
96
84
75
%
%
%
t
ON(MIN)1
Minimum On-Time V
BLANK
= 0V (Note 8) 180 ns
t
ON(MIN)2
Minimum On-Time V
BLANK
= Float (Note 8) 260 ns
t
ON(MIN)3
Minimum On-Time V
BLANK
= 3V8 (Note 8) 340 ns
Gate Driver
R
DS(ON)
Driver Pull-Up R
DS(ON)
2.1 Ω
Driver Pull-Down R
DS(ON)
0.7 Ω
Overvoltage
V
FB(OV)
V
FB
, Overvoltage Lockout Threshold V
FB(OV)
– V
FB(NOM)
in Percent 8 10 12 %
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: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3: The LTC3862E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3862I is guaranteed
over the full –40°C to 125°C operating junction temperature range and
the LTC3862H 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.
Note 4: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Continuous
operation above the specified maximum operating junction temperature
may impair device reliability.
Note 5: Supply current in normal operation is dominated by the current
needed to charge the external MOSFET gates. This current will vary with
supply voltage and the external MOSFETs used.
Note 6: The IC is tested in a feedback loop that adjusts V
FB
to achieve a
specified error amplifier output voltage.
Note 7: Guaranteed by design, not subject to test.
Note 8: The minimum on-time condition is specified for an inductor peak-
to-peak ripple current = 30% (see Minimum On-Time Considerations in the
Applications Information section).
Note 9: The maximum duty cycle limit is derived from an internal
clock that runs at 12x the programmed switching frequency. See the
Applications Information for additional information.
elecTrical characTerisTics
(Notes 2, 3) The l denotes the specifications which apply over the specified
operating junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, RUN = 2V and SS = open, unless
otherwise noted.