LT8705
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise specified.
Efficiency vs Output Current
(Boost Region-Figure 14)
Efficiency vs Output Current
(Buck-Boost Region-Figure 14)
Efficiency vs Output Current
(Buck Region-Figure 14)
100
90
100
90
100
90
80
70
60
80
70
60
80
70
60
50
40
50
40
50
40
V
V
= 36V
= 48V
BURST
V
V
= 48V
= 48V
BURST
V
V
= 72V
= 48V
BURST
IN
OUT
IN
OUT
IN
OUT
30
20
10
0
30
20
10
0
30
20
10
0
CCM
DCM
CCM
DCM
CCM
DCM
10
1000
LOAD CURRENT (mA)
10000
10
1000
LOAD CURRENT (mA)
10000
10
1000
LOAD CURRENT (mA)
10000
100
100
100
8705 G01
8705 G02
8705 G03
Oscillator Frequency
Feedback Voltages
FBOUT Voltages (Five Parts)
1.23
1.22
1.21
1.20
1.23
1.22
1.21
1.20
1.19
1.18
1.17
400
350
300
250
200
150
100
50
V
= 1.2V
V
= 1.2V
C
C
R
T
= 124k
R
R
= 215k
= 365k
T
T
1.19
1.18
1.17
IMON_OUT
IMON_IN
FBOUT
FBIN
0
70 95
–55 –30 –5 20 45
120 145
50
100 125 150
–20
40 60
–50 –25
0
25
75
–40
0
20
80 100 120
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
8705 G04
8795 G05
8705 G06
Maximum Inductor Current Sense
Voltage vs Duty Cycle
Inductor Current Sense Voltage at
Minimum Duty Cycle
Maximum Inductor Current Sense
Voltage at Minimum Duty Cycle
120
100
140
120
120
100
120
100
BOOST REGION
BUCK REGION
80
60
40
80
60
40
100
80
60
40
20
0
80
60
BUCK REGION
BOOST REGION
BUCK REGION
BOOST REGION
20
0
20
0
40
20
0
–20
–40
–60
–80
–20
–40
–60
–80
–40 –20
0
20 40 60 80 100 120
TEMPERATURE (°C)
8705 G09
20
40
60
100
0
80
0.5
1.5
2
1
V
(V)
M2 OR M3 DUTY CYCLE (%)
C
8705 G07
8705 G08
8705p
7
For more information www.linear.com/8705
Linear [ Linear ]
