LTC3772B Datasheet, PDF (5/20 Pages) Linear Technology – Micropower No RSENSE Constant Frequency Step-Down DC/DC Controller

TYPICAL PERFOR A CE CHARACTERISTICS
LTC3772B
Maximum Current Sense
Threshold vs Temperature
300
250
I_PRG = V_IN
200
150
I_PRG = FLOAT
100
I_PRG = GND
50
0
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3772B G13
Soft-Start Time vs Temperature
1100
1000
900
800
700
600
500
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3772B 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
3772B G15
Efficiency vs Load Current
100
V_IN = 3.3V
90
V_IN = 4.2V
80
V_IN = 7V
V_IN = 5V
70
Efficiency vs Load Current
100
90
V_OUT = 3.3V
V_OUT = 2.5V
80
V_OUT = 1.8V
70
60
60
50
V_OUT = 2.5V
FIGURE 5 CIRCUIT
40
1
10
100
1000 10000
LOAD CURRENT (mA)
3772B G16
Start-Up
50
40
10
V_IN = 5V
FIGURE 5 CIRCUIT
100
1000
LOAD CURRENT (mA)
10000
3772B G17
Load Step
V_OUT
1V/DIV
I_TH/RUN
1V/DIV
INDUCTOR
CURRENT
2A/DIV
V_IN = 5V
500µs/DIV
V_OUT = 2.5V
R_LOAD = 1.5Ω
FIGURE 5 CIRCUIT
3772B G18
V_OUT
100mV/DIV
(AC)
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
3772B G19
3772bfa
5