LTC3125_15 Datasheet, PDF (4/18 Pages) Linear Technology – 1.2A Synchronous Step-Up DC/DC Converter with Input Current Limit

LTC3125
TYPICAL PERFORMANCE CHARACTERISTICS (T_A = 25°C unless otherwise noted)
Efficiency vs Load Current,
V_OUT = 5V
100
1
90
80
70
0.1
60
50
40
30
0.01
20
10
0
0.001
V_IN = 4V
V_IN = 3.3V
0.001
0.01
0.1
1
LOAD CURRENT (A)
3125 G03
No-Load Input Current vs V_IN
4.0
3.5
3.0
2.5
V_OUT = 4V
2.0
V_OUT = 3.8V
1.5
V_OUT = 3.3V
1.0
0.5
0
1.5
V_OUT = 2.5V
2
2.5
3
V_IN (V)
3.5
4
3125 G04
Average Input Current Limit
vs Temperature
1.50
NORMALIZED TO 25°C
1.00
0.50
0
–0.50
–1.00
Average Input Current vs R_PROG
1.25
1.00
0.75
0.50
0.25
–1.50
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
3125 G06
Burst Mode Threshold Current
vs V_IN
50
V_OUT = 3.3V
C_OUT = 1500μF
L = 2.2μH
40
0
10 20 30 40 50 60 70 80 90 100 110
R_PROG (kΩ)
3125 G07
Burst Mode Threshold Current
vs V_IN
50
V_OUT = 2.5V
45
C_OUT = 1500μF
L = 2.2μH
40
30
35
30
20
25
10
1.8 2.0 2.2 2.4 2.6 2.8
V_IN (V)
3125 G09
20
1.8
1.9
2.0
2.1
2.2
V_IN (V)
3125 G10
4
Average Input Current Limit vs V_IN
2.0
NORMALIZED TO 25°C
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
1.5 2.0 2.5 3.0 3.5 4.0 4.5
V_IN (V)
3125 G05
Peak Current Limit vs V_IN
2.55
2.50
V_OUT = 3.8V
R_PROG = 0Ω
2.45
2.40
2.35
2.30
2.25
2.20
2.15
2.10
2.05
2.00
1.5 2 2.5 3 3.5 4 4.5
V_IN (V)
5 5.5
3125 G08
Oscillator Frequency vs V_OUT
2
NORMALIZED TO V_OUT = 3.3V
1
0
–1
–2
–3
–4
–5
–6
–7
–8
2.0 2.5 3.0 3.5 4.0 4.5 5.0
V_OUT (V)
3125 G11
3125fa