Datasheet

LTC3442
3
3442fb
For more information www.linear.com/LTC3442
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
OUT
= 3.6V, R
T
= 64.9k, unless otherwise noted (Note 2).
PARAMETER CONDITIONS MIN TYP MAX UNITS
Error Amp Sink Current BURST > 1.25V 300 µA
Burst Threshold (Falling) 0.88 V
Burst Threshold (Rising) 1.12 V
Burst Current Ratio Ratio of I
OUT
to I
BURST
20,000
Input Current Ratio Ratio of I
IN
to I
RLIM
, I
IN
= 0.5A 70,000
R
LIM
Threshold 0.95 V
SHDN/SS Threshold When IC Is Enabled
When EA Is at Max Boost Duty Cycle
l
0.4 0.7
2.2
1.4
2.4
V
V
SHDN/SS Input Current V
SHDN
= 5.5V 0.01 1 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 LTC3442E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical
process controls.
Note 3: Current measurements are performed when the outputs are not
switching.
Note 4: 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 result in device degradation or failure.
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Load
Efficiency and Power Loss
vs Load Efficiency vs Frequency
3442 G01
LOAD (mA)
0.1
EFFICIENCY (%)
1 10 100 1000 10000
90
60
100
80
70
50
40
30
20
Burst Mode
OPERATION
FIXED FREQUENCY
V
IN
= 5V
V
IN
= 3.3V
V
IN
= 2.5V
V
IN
= 5V
V
IN
= 3.3V
V
IN
= 2.5V
V
OUT
= 3.3V
600kHz
LOAD CURRENT (mA)
0.1
EFFICIENCY (%)
1 10 100 1000 10000
3442 G02
90
60
40
30
20
100
80
70
50
10
1
0.1
1000
100
POWER LOSS (mW)
Burst Mode
OPERATION
FIXED FREQUENCY
POWER LOSS
V
IN
= 3.6V
V
OUT
= 3.3V
FREQUENCY (kHz)
400
EFFICIENCY (%)
2000
3442 G03
800
1200
1600
600
1000
1400
1800
96
94
92
90
88
86
84
82
80
WITHOUT SCHOTTKY DIODES
WITH SCHOTTKY DIODES
V
IN
= 3.6V
V
OUT
= 3.3V
(T
A
= 25°C unless otherwise specified).