Datasheet

LTC3425
5
3425f
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Converter Efficiency
for V
OUT
= 3.3V
Converter Efficiency for 2-, 3- and
4-Phase Operation
Efficiency Comparison of
Discontinuous Mode and Forced
Continuous Mode at Light Loads
for V
IN
= 2.4V, V
OUT
= 3.3V
Converter No Load Input Current
vs V
IN
(Burst Mode Operation)
Oscillator Frequency Peak Current Limit
OUTPUT CURRENT (mA)
0.1 1
70
EFFICIENCY (%)
80
90
10 100 1000 10000
3425 G11
60
50
40
30
20
10
0
100
V
IN
= 2.4V
V
IN
= 1.2V
V
IN
= 1.2V
V
IN
= 2.4V
T
A
= 25°C
Burst Mode OPERATION
1MHz/PHASE
OUTPUT CURRENT (mA)
0.1 1
70
EFFICIENCY (%)
80
90
10 100 1000 10000
3425 G12
60
0
10
20
30
40
50
100
T
A
= 25°C
V
IN
= 3.3V
V
IN
= 3.3V
V
IN
= 2.4V
V
IN
= 2.4V
Burst Mode OPERATION
1MHz/PHASE
Converter Efficiency
for V
OUT
= 5V
LOAD (mA)
100
80
EFFICIENCY (%)
84
82
86
88
90
92
94
96
1000 10000
3425 G13
98
4 PHASE
T
A
= 25°C
V
IN
= 2.4V
V
OUT
= 3.3V
1MHz/PHASE
3 PHASE
2 PHASE
CONVERTER OUTPUT CURRENT (mA)
1
40
EFFICIENCY (%)
50
60
70
80
10 100 1000
3425 G14
30
20
10
0
90
100
T
A
= 25°C
1MHz/PHASE
DISCONTINUOUS
MODE
FORCED
CONTINUOUS
MODE
LOAD (mA)
1
40
EFFICIENCY (%)
50
60
70
80
10 100 1000
3425 G15
30
20
10
0
90
100
T
A
= 25°C
1MHz/PHASE
DISCONTINUOUS
MODE
FORCED
CONTINUOUS
MODE
Efficiency Comparison of
Discontinuous Mode and Forced
Continuous Mode at Light Loads
for V
IN
= 3.3V, V
OUT
= 5V
V
IN
(V)
1.5
140
120
100
80
60
40
20
0
3.0 4.0
3425 G16
2.0 2.5
3.5 4.5
CONVERTER INPUT CURRENT (µA)
T
A
= 25°C
V
OUT
= 3.3V
V
OUT
= 5V
R
T
(kΩ)
1
1
FREQUENCY (MHz)
10
10 100
3425 G17
T
A
= 25°C
I
LIM
RESISTOR (kΩ)
60
PEAK CURRENT IN EACH PHASE (A)
1.4
1.6
1.8
120 160
3425 G18
1.2
1.0
80 100
140 180 200
0.8
0.6
T
A
= 25°C
Effective R
DS(ON)
V
OUT
(V)
2.5
R
DS(ON)
(ALL FOUR PHASES IN PARALLEL)
0.065
0.060
0.055
0.050
0.045
0.040
4.5
3425 G19
3
3.5
4
5
T
A
= 25°C
PMOS
NMOS