LTC3442
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.
PARAMETER
Burst Current Ratio
Input Current Ratio
R
LIM
Threshold
SHDN/SS Threshold
SHDN/SS Input Current
When IC is Enabled
When EA is at Max Boost Duty Cycle
V
SHDN
= 5.5V
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
Ratio of I
OUT
to I
BURST
Ratio of I
IN
to I
RLIM
, I
IN
= 0.5A
MIN
TYP
20,000
70,000
0.95
MAX
UNITS
V
1.4
2.4
1
V
V
µA
0.4
0.7
2.2
0.01
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The LTC3442E is guaranteed to meet performance specifications
from 0°C to 70°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
Efficiency vs Load
100
Burst Mode
90 OPERATION V = 5V
IN
80 V
IN
= 3.3V
V
IN
= 3.3V
100
Burst Mode
90 OPERATION
POWER LOSS (mW)
EFFICIENCY (%)
70
60
50
40
30
20
0.1
1
10
100
LOAD (mA)
V
OUT
= 3.3V
600kHz
1000
10000
3442 G01
EFFICIENCY (%)
EFFICIENCY (%)
V
IN
= 5V
V
IN
= 2.5V
FIXED FREQUENCY
Input Current Mirror Linearity
1.00
0.90
0.80
R
LIM
VOLTAGE (V)
V
IN
= 3.6V
V
OUT
= 3.3V
R
LIM
= 133k
% CHANGE (NORMALIZED)
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
0 .05 .10 .15 .20 .25 .30 .35 .40 .45 .50
INPUT CURRENT (A)
3442 G04
4
2
0
–2
–4
–6
–8
2.5
3.0
3.5
V
IN
(V)
3442 G05
% CHANGE (NORMALIZED)
U W
V
IN
= 2.5V
(T
A
= 25°C unless otherwise specified).
Efficiency vs Frequency
1000
Efficiency and Power Loss vs Load
96
94
100
POWER LOSS
10
FIXED FREQUENCY
1
V
IN
= 3.6V
V
OUT
= 3.3V
1
10
100
1000
LOAD CURRENT (mA)
80
70
60
50
40
30
20
0.1
92
90
88
86
84
82
V
IN
= 3.6V
V
OUT
= 3.3V
WITH SCHOTTKY DIODES
WITHOUT SCHOTTKY DIODES
0.1
10000
80
400 600 800 1000 1200 1400 1600 1800 2000
FREQUENCY (kHz)
3442 G03
3442 G02
Average Input Current Limit
vs V
IN
(Normalized)
8
V
OUT
= 3.3V
1MHz
6
Average Input Current Limit
vs Frequency (Normalized)
15
V
IN
= 5V
10
V
OUT
SHORTED
5
0
V
OUT
DROPS 10%
–5
4.0
4.5
5.0
–10
0.50
0.75
1.00 1.25 1.50
FREQUENCY (MHz)
1.75
2.00
3442 TA01b
3442f
3
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
