LTC3809-1_15 Datasheet, PDF (4/24 Pages) Linear Technology – No RSENSE, Low Input Voltage, Synchronous DC/DC Controller with Output Tracking

LTC3809-1
TYPICAL PERFORMANCE CHARACTERISTICS ^TA ^{= 25°C, unless otherwise noted.}
Efficiency vs Load Current
100
FIGURE 8 CIRCUIT
95
V_OUT = 2.5V
90 ^{VOUT = 3.3V}
85
V_OUT = 1.2V
80
75
V_OUT = 1.8V
70
65
60
1
MODE = V_IN
V_IN = 5V
10
100
1k
10k
LOAD CURRENT (mA)
38091 G01
Load Step
(Burst Mode Operation)
Efficiency vs Load Current
100
FIGURE 8 CIRCUIT
95 V_IN = 5V, V_OUT = 2.5V
90
85
BURST MODE
80
(MODE = V_IN)
75
FORCED
70
CONTINUOUS
(MODE = 0V)
65
60
55
50
1
PULSE SKIPPING
(MODE = 0.6V)
10
100
1k
10k
LOAD CURRENT (mA)
38091 G02
Load Step
(Forced Continuous Mode)
Maximum Current Sense Voltage
vs I_TH Pin Voltage
100
Burst Mode OPERATION
(I_TH RISING)
80
Burst Mode OPERATION
(I_TH FALLING)
FORCED CONTINUOUS
60
MODE
PULSE SKIPPING
40
MODE
20
0
–20
0.5
1
1.5
I_TH VOLTAGE (V)
2
38091 G03
Load Step
(Pulse-Skipping Mode)
V_OUT
200mV/DIV
AC COUPLED
I_L
2A/DIV
V_OUT
200mV/DIV
AC COUPLED
I_L
2A/DIV
V_OUT
200mV/DIV
AC COUPLED
I_L
2A/DIV
100μs/DIV
V_IN = 3.3V
V_OUT = 1.8V
I_LOAD = 300mA TO 3A
MODE = V_IN
FIGURE 8 CIRCUIT
38091 G04
100μs/DIV
V_IN = 3.3V
V_OUT = 1.8V
I_LOAD = 300mA TO 3A
MODE = 0V
FIGURE 8 CIRCUIT
38091 G05
100μs/DIV
V_IN = 3.3V
V_OUT = 1.8V
I_LOAD = 300mA TO 3A
MODE = V_FB
FIGURE 8 CIRCUIT
Start-Up with Internal Soft-Start
(TRACK/SS = V_IN)
Start-Up with External Soft-Start
(C_SS = 10nF)
V_OUT
1.8V
500mV/DIV
V_OUT
1.8V
500mV/DIV
38091 G06
4
200μs/DIV
V_IN = 4.2V
R_LOAD = 1
FIGURE 8 CIRCUIT
38091 G07
1ms/DIV
V_IN = 4.2V
R_LOAD = 1
FIGURE 8 CIRCUIT
38091 G08
38091fc