Datasheet

LTC3125
4
3125fa
Burst Mode Threshold Current
vs V
IN
Oscillator Frequency vs V
OUT
Effi ciency vs Load Current,
V
OUT
= 5V
Average Input Current Limit vs V
IN
Average Input Current Limit
vs Temperature
Average Input Current vs R
PROG
Peak Current Limit vs V
IN
TYPICAL PERFORMANCE CHARACTERISTICS
(T
A
= 25°C unless otherwise noted)
No-Load Input Current vs V
IN
Burst Mode Threshold Current
vs V
IN
V
IN
(V)
1.5
AVERAGE INPUT CURRENT LIMIT CHANGE (%)
–0.5
0
0.5
3.0
4.0
3125 G05
–1.0
–1.5
–2.0
2.0 2.5 3.5
1.0
1.5
2.0
NORMALIZED TO 25°C
4.5
TEMPERATURE (°C)
–50
–1.50
AVERAGE INPUT CURRENT LIMIT CHANGE (%)
–1.00
–0.50
0
0.50
1.50
–25
02550
3125 G06
75 100
1.00
NORMALIZED TO 25°C
V
IN
(V)
1.5
INPUT CURRENT (A)
2.15
2.45
2.50
2.55
3
4
4.5
3125 G08
2.05
2.35
2.25
2.10
2.40
2.00
2.30
2.20
2 2.5
3.5
5
5.5
V
OUT
= 3.8V
R
PROG
= 0
V
OUT
(V)
2.0
–8
FREQUENCY CHANGE (%)
–7
–5
–4
–3
2
–1
2.5
3.5
4.0
3125 G11
–6
0
1
–2
3.0
4.5
5.0
NORMALIZED TO V
OUT
= 3.3V
LOAD CURRENT (A)
0.001
40
EFFICIENCY (%)
POWER LOSS (W)
50
60
70
80
0.01 0.1 1
3125 G03
30
20
10
0
90
100
0.1
0.01
0.001
1
V
IN
= 4V
V
IN
= 3.3V
V
IN
(V)
1.5
I
IN
(mA)
1.5
2.0
2.5
3
4
3125 G04
1.0
0.5
0
2 2.5 3.5
3.0
3.5
4.0
V
OUT
= 4V
V
OUT
= 2.5V
V
OUT
= 3.8V
V
OUT
= 3.3V
R
PROG
(k)
10 20 30 40 50 70 80 90 100
0
AVERAGE INPUT CURRENT LIMIT (A)
0.25
0.50
0.75
1.00
60 110
3125 G07
1.25
V
IN
(V)
1.8
LOAD CURRENT (mA)
30
40
2.6
3125 G09
20
10
2.0
2.2
2.4
2.8
50
V
OUT
= 3.3V
C
OUT
= 1500µF
L = 2.2µH
V
IN
(V)
1.8
20
LOAD CURRENT (mA)
25
30
35
40
45
50
1.9 2.0 2.1 2.2
3125 G10
V
OUT
= 2.5V
C
OUT
= 1500µF
L = 2.2µH