Datasheet

LTC3853
4
3853fa
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: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LTC3853UJ: T
J
= T
A
+ (P
D
• 33°C/W)
Note 3: The LTC3853 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3853E is guaranteed to meet performance specifications
from 0°C to 85°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
LTC3853I is guaranteed over the full –40°C to 125°C operating junction
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C (Note 3), V
IN
= 15V, V
RUN1,2,3
= 5V, unless otherwise noted.
temperature range. The maximum ambient temperature consistent with
these specifications is determined by specific operating conditions in
conjunction with board layout, the rated package thermal resistance and
other environmental factors.
Note 4: The LTC3853 is tested in a feedback loop that servos V
ITH1,2,3
to a
specified voltage and measures the resultant V
FB1,2,3
.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 6: Rise and fall times are measured using 10% and 90% levels.
Delay times are measured using 50% levels.
Note 7: The minimum on-time condition is specified for an inductor
peak-to-peak ripple current ≥40% of I
MAX
(see Minimum On-Time
Considerations in the Applications Information section).
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
INTV
CC
Linear Regulator
V
INTVCC
Internal V
CC
Voltage 7V < V
IN
< 24V 4.8 5 5.2 V
V
LDO
INT INTV
CC
Load Regulation I
CC
= 0mA to 50mA 0.5 2 %
V
EXTVCC
EXTV
CC
Switchover Voltage EXTV
CC
Ramping Positive
l
4.5 4.7 V
V
LDO
EXT EXTV
CC
Voltage Drop I
CC
= 20mA, V
EXTVCC
= 5V 30 75 mV
V
LDOHYS
EXTV
CC
Hysteresis 200 mV
Oscillator and Phase-Locked Loop
f
NOM
Nominal Frequency V
FREQ
= 1.2V 450 500 550 kHz
f
LOW
Lowest Frequency V
FREQ
= 0V 210 250 290 kHz
f
HIGH
Highest Frequency V
FREQ
≥ 2.4V 670 750 830 kHz
Ph
TRIPLE
Channel 2-Channel 1 Phase
Channel 3-Channel 2 Phase
Channel 1-Channel 3 Phase
120
120
120
Deg
Deg
Deg
Ph
DUAL(2+1)
Channel 2-Channel 1 Phase
Channel 3-Channel 2 Phase
Channel 1-Channel 3 Phase
V
FB2
Tied to V
IN
Through 200kΩ 180
60
120
Deg
Deg
Deg
R
MODE/PLLIN
MODE/PLLIN Input Resistance 250 kΩ
I
FREQ
Phase Detector Output Current
Sinking Capability
Sourcing Capability
f
MODE
< f
OSC
f
MODE
> f
OSC
–13
13
µA
µA
PGOOD Outputs
V
PGL
PGOOD Voltage Low I
PGOOD
= 2mA 0.1 0.3 V
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 5V ±2 µA
V
PG
PGOOD Trip Level V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
–5
5
–7.5
7.5
–10
10
%
%