Datasheet

LTC3546
4
3546fc
For more information www.linear.com/3546
elecTrical characTerisTics
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
CCA
= 3.6V, unless otherwise specified. (Note 2)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
SW1D(LKG)
Switch Leakage Current SW1D V
IN
= 6V
V
ITH1
= V
ITH2
= 0V
V
RUN1
= V
RUN2
= 0V
0.01 1 µA
I
SW2A/B(LKG)
Switch Leakage Current SW2A/B V
IN
= 6V
V
ITH2
= 0V
V
RUN2
= 0V
0.01 1 µA
V
UVLO
Undervoltage Lockout Threshold V
IN1
, V
IN2
, V
CCA
, V
CCD
Rising
V
IN1
, V
IN2
, V
CCA
, V
CCD
Falling
2.03
1.86
2.14
1.97
2.2
2.03
V
V
T
PGOOD1
Threshold for Power Good
Percentage Deviation from Regulated V
FB1
(Typically 0.6V).
V
FB1
Ramping Up, V
SYNC/MODE
= 0V –8 %
T
PGOOD2
Threshold for Power Good
Percentage Deviation from Regulated V
FB2
(Typically 0.6V).
V
FB2
Ramping Up, V
SYNC/MODE
= 0V –8 %
R
PGOOD1
Power Good Pull-Down On-Resistance 132 300
Ω
R
PGOOD2
Power Good Pull-Down On-Resistance 132 300
Ω
t
SS
Soft-Start Internal Time. V
FB
from 0% to 95%, V
TRACK/SS
Is Floating 0.8 1.2 1.9 ms
V
RUN1
, V
RUN2
,
V
PHASE
RUN1, RUN2, and PHASE Threshold 0.3 0.8 1.2 V
I
RUN1
, I
RUN2
,
I
PHASE
RUN1, RUN2, and PHASE Leakage Current V
IN
= 6V, V
PHASE
= 3V, V
RUN1
= V
RUN2
= 3V ±0.01 ±1 µA
VTL
SYNC/MODE
SYNC/MODE Threshold Voltage Low to Put
the Part into Pulse-Skipping Mode
0.5 V
VTH
SYNC/MODE
SYNC/MODE Threshold Voltage High to
Put the Part into Burst Mode Operation
V
IN
– 0.5 V
V
SYNC/MODE
SYNC/MODE Threshold for Clock
Synchronization
0.3 0.8 1.2 V
I
SYNC/MODE
SYNC/MODE Leakage Current V
IN
= 6V, V
SYNC/MODE
= 3V ±0.01 ±1 µA
VTH
FREQ
FREQ Threshold Voltage High V
IN
– 0.85 V
I
BMC1
, I
BMC2
BMC1, BMC2 Leakage Current V
IN
= 6V, V
BMC
= 3V ±0.4 µA
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 LTC3546 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3546E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 125°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3546I is guaranteed
to meet performance specifications over the full –40°C to 125°C operating
junction 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
impedance and other environmental factors.
Note 3: The LTC3546 is tested in feedback loop which servos V
FB1
to the
midpoint for the error amplifier (V
ITH1
= 0.6V) and V
FB2
to the midpoint for
the error amplifier (V
ITH2
= 0.6V).
Note 4: Total supply current is higher due to the internal gate charge being
delivered at the switching frequency.
Note 5: Variable frequency operation with resistor is guaranteed by design
and is subject to duty cycle limitations.
Note 6: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 7: T
J
is calculated from the ambient temperature, T
A
, and power
dissipation, P
D
, according to the following formula:
T
J
= T
A
+ (P
D
• 34°C/W)
Note 8: Minimum current limit is guaranteed by design and correlation to
the R
DS(ON)1D
, I
LIM1
and I
LIM2
measurements.