LTC3355_15 Datasheet, PDF (5/20 Pages) Linear Technology – 20V 1A Buck DC/DC with Integrated SCAP Charger and Backup Regulator

LTC3355
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise noted
Buck Efficiency
100
90
80
70
60
50
40
30
V_OUT = 4V
MODE = HIGH
20
V_IN = 18V
10
V_IN = 12V
V_IN = 6V
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
LOAD CURRENT (A)
3355 G01
Maximum Boost Load Current
1.2 _{VOUT = 4V}
1.0
0.8
0.6
0.4
0.2
0
0.75 1.25 1.75 2.25 2.75 3.25 3.75
V_CAP (V)
3355 G04
Buck Frequency
vs Feedback Voltage
1000
900
800
700
600
500
400
300
200
100
0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
FB (V)
3355 G07
Boost Efficiency
100
90
80
70
60
50
40
30
V_CAP = 2.4V
MODE = HIGH
20
V_OUT = 3.3V
10
V_OUT = 4V
V_OUT = 5V
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
LOAD CURRENT (A)
3355 G02
Buck Switch Voltage Drop
700
600
500
400
300
200
100
0
0 100 200 300 400 500 600 700 800 900 1000
SWITCH CURRENT (mA)
3355 G05
Typical Minimum Buck Input
Voltage (V_OUT = 3.3V)
4.6
V_OUT = 3.3V
4.4 ^{L = 6.8µH}
INPUT CURRENT SET RESISTOR = 0.05Ω
4.2
4.0
3.8
3.6
3.4
3.2
3.0
1
10
100
V_OUT LOAD CURRENT (mA)
1000
3355 G08
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Maximum Buck Load Current
1.20
1.00
0.80
0.60
0.40
0.20 VOUT = 4V
L = 6.8µH
INPUT CURRENT SET RESISTOR = 0Ω
0
4 6 8 10 12 14 16 18 20
V_IN (V)
3355 G03
Oscillator Frequency
vs Temperature
1200
1150
1100
1050
1000
950
900
850
800
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3355 G06
Typical Minimum Buck Input
Voltage (V_OUT = 5V)
6.3
V_OUT = 5V
6.1 ^{L = 6.8µH}
INPUT CURRENT SET RESISTOR = 0.05Ω
5.9
5.7
5.5
5.3
5.1
4.9
4.7
4.5
1
10
100
V_OUT LOAD CURRENT (mA)
1000
3355 G09
3355fb
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