LTC3646-1_15 Datasheet, PDF (5/28 Pages) Linear Technology – 40V, 1A Synchronous Step-Down Converter

LTC3646/LTC3646-1
TYPICAL PERFORMANCE CHARACTERISTICS
T_A = 25°C, SVIN/PVIN = 12V, f_O = 1MHz unless otherwise noted.
Efficiency vs Load Current,
Burst Mode Operation
100
V_OUT = 1.8V
90 f_O = 1.5MHz
80
70
60
50
40
30
20
10
0
0.001
V_IN = 5V
V_IN = 8V
V_IN = 12V
0.01
0.1
1
LOAD CURRENT (A)
36461 G01
Efficiency vs Load Current,
Forced Continuous Mode Operation
100
V_OUT = 1.8V
90 f_O = 1.5MHz
80
70
60
50
40
30
20
10
0
0.001
V_IN = 5V
V_IN = 8V
V_IN = 12V
0.01
0.1
1
LOAD CURRENT (A)
36461 G02
Efficiency vs Input Voltage,
Burst Mode Operation
100
95
LOAD = 500mA
90
85
LOAD = 1A
80
75
LOAD = 100mA
70
65 L = 6.8µH
V_OUT = 3.3V
60
0 5 10 15 20 25 30
INPUT VOLTAGE (V)
35 40
36461 G04
Reference Voltage
vs Temperature
608
606
604
602
600
598
596
594
592
–50 –30 –10 10 30 50 70 90 110 130 150
TEMPERATURE (°C)
36461 G05
Switch Pin Leakage
vs Temperature and Supply
20
V_DS = 12V, MAIN SWITCH
18
V_DS = 12V, SYNCHRONOUS SWITCH
16
V_DS = 40V, MAIN SWITCH
V_DS = 40V, SYNCHRONOUS SWITCH
14
12
10
8
6
4
2
0
–50 –30 –10 10 30 50 70 90 110 130 150
TEMPERATURE (°C)
36461 G07
Oscillator Internal Set Frequency
vs Temperature
2.50 _{VRT = VINTVCC}
2.45
2.40
2.35
2.30
2.25
2.20
2.15
2.10
2.05
2.00
–40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
36461 G08
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Efficiency vs Load Current
100
90 ^{Burst Mode OPERATION}
80
70
60
50
40
FORCED CONTINUOUS
OPERATION
30
20
10
0
0.001
V_OUT = 5V
V_OUT = 3.3V
0.01
0.1
1
LOAD CURRENT (A)
36461 G03
R_DS(ON) vs Temperature
0.35
0.30
MAIN SWITCH
0.25
0.20
0.15
0.10
SYNCHRONOUS SWITCH
0.05
0
–50 –30 –10 10 30 50 70 90 110 130 150
TEMPERATURE (°C)
36461 G06
Oscillator Externally Set Frequency
vs Temperature
1.8 _{RRT = 60k}
1.7
1.6
1.5
1.4
1.3
1.2
–40 –20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
36461 G09
36461fb
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