LTC3772_15 Datasheet, PDF (5/20 Pages) Linear Technology – Micropower No RSENSE Constant Frequency Step-Down DC/DC Controller

TYPICAL PERFOR A CE CHARACTERISTICS
LTC3772
Maximum Current Sense
Threshold vs Temperature
300
I_PRG = V_IN
250
200
I_PRG = FLOAT
150
I_PRG = GND
100
50
0
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3772 G13
Soft-Start Time vs Temperature
1000
900
800
700
600
500
400
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3772 G14
Foldback Frequency
vs Temperature
230 _{VFB = 0V}
220
210
200
190
180
170
160
150
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3772 G15
Efficiency vs Load Current
95
V_IN = 3.3V
90
V_IN = 4.2V
85
V_IN = 5V
80
V_IN = 7V
75
70
65
V_OUT = 2.5V
60
FIGURE 5 CIRCUIT
1
10
100
1000 10000
LOAD CURRENT (mA)
3772 G16
Efficiency vs Load Current
100
FIGURE 5 CIRCUIT
V_OUT = 3.3V
90
V_OUT = 2.5V
80
V_OUT = 1.8V
70
60
50
1
10
100
1000
LOAD CURRENT (mA)
10000
3772 G17
Start-Up
Load Step
V_OUT
1V/DIV
I_TH/RUN
1V/DIV
I_L
2A/DIV
V_IN = 5V
500µs/DIV
V_OUT = 2.5V
FIGURE 5 CIRCUIT
3772 G18
V_OUT
100mV/DIV
AC COUPLED
I_L
2A/DIV
I_LOAD
2A/DIV
V_IN = 5V
20µs/DIV
V_OUT = 2.5V
I_LOAD = 100mA TO 1.5A
FIGURE 5 CIRCUIT
3772 G19
3772f
5