LT8705
7
8705ff
For more information www.linear.com/LT8705
Typical perForMance characTerisTics
FBOUT Voltages (Five Parts)Feedback Voltages
Oscillator Frequency
Maximum Inductor Current Sense
Voltage vs Duty Cycle
Inductor Current Sense Voltage at
Minimum Duty Cycle
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)
LOAD CURRENT (mA)
10
0
EFFICIENCY (%)
20
30
40
50
60
70
100
1000
80
90
100
V
IN
= 36V
V
OUT
= 48V
10
10000
BURST
CCM
DCM
LOAD CURRENT (mA)
10
0
EFFICIENCY (%)
20
30
40
50
60
70
100
1000
80
90
100
V
IN
= 48V
V
OUT
= 48V
10
10000
BURST
CCM
DCM
LOAD CURRENT (mA)
10
0
EFFICIENCY (%)
20
30
40
50
60
70
100
1000
80
90
100
V
IN
= 72V
V
OUT
= 48V
10
10000
BURST
CCM
DCM
TEMPERATURE (°C)
–55
1.17
PIN VOLTAGE (V)
1.18
1.19
1.20
1.21
–5 45
95
145
8705 G04
1.22
1.23
–30 20
70
120
IMON_OUT
IMON_IN
FBOUT
FBIN
V
C
= 1.2V
TEMPERATURE (°C)
–45
FBOUT VOLTAGE (V)
1.21
1.22
1.23
30 80
8795 G05
1.20
1.19
–20 5
55 105 130
1.18
1.17
V
C
= 1.2V
TEMPERATURE (°C)
–40
FREQUENCY (kHz)
200
300
120
8705 G06
100
0
0
40
80
–20
20
60
100
400
R
T
= 124k
R
T
= 215k
R
T
= 365k
150
250
50
350
M2 OR M3 DUTY CYCLE (%)
0
100
120
140
80
8705 G07
80
60
20 40 60 100
40
20
0
|CSP-CSN| (mV)
BUCK REGION
BOOST REGION
V
C
(V)
0.5
–80
CSN-CSP (mV)
CSP-CSN (mV)
–40
–20
0
20
40
60
1
1.5
80
100
120
BUCK REGION
BOOST REGION
–60
–80
–40
–20
0
20
40
60
80
100
120
–60
2
Maximum Inductor Current Sense
Voltage at Minimum Duty Cycle
TEMPERATURE (°C)
–40
0
|CSP-CSN| (mV)
20
40
60
80
100
120
0 40 80–20 20 60 100 120
BOOST REGION
BUCK REGION
T
A
= 25°C unless otherwise specified.
