Typical Performance Characteristics - Linear Technology Analog Devices LT8708 Datasheet

TYPICAL PERFORMANCE CHARACTERISTICS

Efficiency vs Output Current
(Boost Region – Page 59)
100
90
80
70
60
50
40
30
20
10
0
0.01 0.1
LOAD CURRENT (A)
Feedback Voltages
Feedback Voltages
1.23
V = 1.2V
C
1.22
1.21
1.20
1.19
1.18
1.17
–45 –20 5 30 55 80
TEMPERATURE (°C)
Maximum Inductor Current Sense
Voltage vs Duty Cycle
140
120
BUCK REGION
100
80
BOOST REGION
60
40
20
0
0 20 40 60
M2 OR M3 DUTY CYCLE (%)
Efficiency vs Output Current
(Buck Region – Page 59)
100
90
80
70
60
50
40
V = 38V
IN 30
V = 47.4V
OUT
20
HCM
DCM
10
CCM
0
1 10
0.01
8708 G01
Feedback Voltages (Five Parts)
1.23
V = 1.2V
C
1.22
1.21
1.20
FBOUT
1.19
FBIN
IMON_INP
IMON_INN
1.18
IMON_ON
IMON_OP
1.17
105 130 155 –45 –20
8708 G04
Inductor Current Sense Voltage at
Minimum Duty Cycle
100
80
60
40
20
BUCK REGION
0
–20
–40
–60
–80
–100
0.5
80 100
8708 G07
For more information
V = 51.5V
IN
V = 47.4V
OUT
HCM
DCM
CCM
0.1 1 10
LOAD CURRENT (A)
8708 G02
5 30 55 80 105 130 155
TEMPERATURE (°C)
8708 G05
100
80
60
40
20
0
BOOST REGION
–20
–40
–60
–80
–100
1 1.5 2
V (V)
C
8708 G08
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LT8708
Efficiency vs Output Current
(Buck–Boost Region – Page 59)
100
90
80
70
60
50
40
V
30
IN
V
OUT
20
10
0
0.01 0.1 1
LOAD CURRENT (A)
Oscillator Frequency
Oscillator Frequency
400
R = 124k
T
350
300
250
R = 215k
T
200
150
R = 365k
T
100
50
0
–45 –20 5 30 55 80 105 130 155
TEMPERATURE (°C)
Maximum Inductor Current Sense
Voltage at Minimum Duty Cycle
Voltage at Minimum Duty Cycle
120
BOOST REGION
100
80
BUCK REGION
60
40
20
0
–45 –20 5 30 55 80 105 130 155
TEMPERATURE (°C)
= 48V
= 47.4V
HCM
DCM
CCM
10
8708 G03
8708 G06
8708 G09
Rev 0
9