Datasheet

LTC3442
3
3442fa
V
IN
(V)
2.5
% CHANGE (NORMALIZED)
4.0
5.0
3442 G05
3.0 3.5 4.5
8
6
4
2
0
–2
–4
–6
–8
V
OUT
= 3.3V
1MHz
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
FREQUENCY (MHz)
0.50
% CHANGE (NORMALIZED)
0.75
1.00
1.25 1.50
3442 TA01b
1.75
15
10
5
0
–5
–10
2.00
V
IN
= 5V
V
OUT
SHORTED
V
OUT
DROPS 10%
PARAMETER CONDITIONS MIN TYP MAX UNITS
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 ● 0.4 0.7 1.4 V
When EA is at Max Boost Duty Cycle 2.2 2.4 V
SHDN/SS Input Current V
SHDN
= 5.5V 0.01 1 µA
ELECTRICAL CHARACTERISTICS
The ● 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 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 –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 PERFOR A CE CHARACTERISTICS
UW
Efficiency vs Load
Efficiency and Power Loss vs Load
Efficiency vs Frequency
Input Current Mirror Linearity
Average Input Current Limit
vs V
IN
(Normalized)
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
INPUT CURRENT (A)
0
1.00
0.90
0.80
0.60
0.70
0.50
0.40
0.30
0.20
0.10
0.00
.40
3442 G04
.10.05 .15 .25 .35 .45
.20
.30
.50
R
LIM
VOLTAGE (V)
V
IN
= 3.6V
V
OUT
= 3.3V
R
LIM
= 133k
(T
A
= 25°C unless otherwise specified).
Average Input Current Limit
vs Frequency (Normalized)