LTC3899_15 Datasheet, PDF (8/38 Pages) Linear Technology – 60V Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller

LTC3899
Typical Performance Characteristics
Efficiency and Power Loss
vs Output Current (Boost)
100
90 ^{BURST EFFICIENCY}
80
FCM LOSS
PULSE-SKIPPING
70
EFFICIENCY
10000
1000
60
100
PULSE-SKIPPING
50 _LOSS
40 BURST
10
30 ^LOSS
20
10
0
0.0001
V_IN = 5V 1
V_OUT = 10V
0.001 0.01
FCM EFFICIENCY
0.1
0.1
1
10
OUTPUT CURRENT (A)
3899 G10
Efficiency
vs Input Voltage (Boost)
100
DRVSET = INTV_CC
98
DRVSET = 0V
96
94
92
90
88
86
84
FIGURE 12 CIRCUIT
82
V_OUT = 10V
I_LOAD = 2A
80
2
4
6
8
10
12
INPUT VOLTAGE (V)
3899 G11
Shutdown (RUN) Threshold
vs Temperature
1.4
1.35
1.3
RISING
1.25
1.2
FALLING
1.15
1.1
1.05
1
-75 -50 -25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3899 G12
Load Step (Boost)
Forced Continuous Mode
V_OUT
500mV/DIV
AC COUPLED
Load Step (Boost)
Pulse-Skipping Mode
V_OUT
500mV/DIV
AC COUPLED
Load Step (Boost)
Burst Mode Operation
V_OUT
500mV/DIV
AC COUPLED
IL
5A/DIV
IL
5A/DIV
IL
5A/DIV
100µs/DIV
V_IN = 5V
V_OUT = 10V
FIGURE 12 CIRCUIT
3899 G13
100µs/DIV
V_IN = 5V
V_OUT = 10V
FIGURE 12 CIRCUIT
3899 G14
100µs/DIV
V_IN = 5V
V_OUT = 10V
FIGURE 12 CIRCUIT
3899 G15
Inductor Current at Light Load
(Boost)
FORCED
CONTINUOUS
MODE
Burst Mode
OPERATION
5A/DIV
PULSE-
SKIPPING
MODE
2µs/DIV
V_IN = 7V
V_OUT = 10V
I_LOAD = 1mA
FIGURE 12 CIRCUIT
3899 G16
Soft Start-Up (Boost)
RUN3
5V/DIV
V_OUT3
2V/DIV
GND
2ms/DIV
FIGURE 12 CIRCUIT
3899 G17
8
For more information www.linear.com/LTC3899
Boost Regulated Feedback
Voltage vs Temperature
1.212
1.209
1.206
1.203
1.2
1.197
1.194
1.191
1.188
-75 -50 -25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3899 G18
3899f