Datasheet

LT1934/LT1934-1
4
1934fe
TYPICAL PERFORMANCE CHARACTERISTICS
LT1934-1 Effi ciency, V
OUT
= 3.3V Current Limit vs Temperature Off Time vs Temperature
Frequency Foldback V
FB
vs Temperature
SHDN Bias Current
vs SHDN Voltage
LT1934 Effi ciency, V
OUT
= 5V LT1934 Effi ciency, V
OUT
= 3.3V LT1934-1 Effi ciency, V
OUT
= 5V
LOAD CURRENT (mA)
60
EFFICIENCY (%)
70
80
90
100
0.1 10 100
1934 G01
50
1
LT1934
V
OUT
= 5V
L = 47μH
T
A
= 25°C
V
IN
= 12V
V
IN
= 24V
LOAD CURRENT (mA)
60
EFFICIENCY (%)
70
80
90
100
0.1 10 100
1934 G02
50
1
LT1934
V
OUT
= 3.3V
L = 47μH
T
A
= 25°C
V
IN
= 24V
V
IN
= 5V
V
IN
= 12V
LOAD CURRENT (mA)
0.1
50
EFFICIENCY (%)
80
90
100
1 10 100
1934 G03
70
60
LT1934-1
V
OUT
= 5V
L = 150μH
T
A
= 25°C
V
IN
= 24V
V
IN
= 12V
LOAD CURRENT (mA)
0.1
50
EFFICIENCY (%)
80
90
100
1 10 100
1934 G04
70
60
LT1934-1
V
OUT
= 3.3V
L = 100μH
T
A
= 25°C
V
IN
= 24V
V
IN
= 12V
TEMPERATURE (°C)
–50 –25
0
SWITCH CURRENT LIMIT (mA)
200
500
0
50
75
1934 G05
100
400
300
25
100
125
LT1934
LT1934-1
TEMPERATURE (°C)
–50
OFF TIME (μs)
2.0
2.5
3.0
25 75
1934 G06
1.5
1.0
–25 0
50 100 125
0.5
0
FEEDBACK PIN VOLTAGE (V)
0
SWITCH OFF TIME (μs)
6
8
10
0.6
1.0
1934 G07
4
2
0
0.2 0.4 0.8
12
14
16
1.2
T
A
= 25oC
TEMPERATURE (°C)
–50 –25
1.22
FEEDBACK VOLTAGE (V)
1.24
1.27
0
50
75
1934 G08
1.23
1.26
1.25
25
100
125
SHDN PIN VOLTAGE (V)
0
0
SHDN PIN CURRENT (μA)
0.5
1.0
1.5
2.0
2468
1934 G09
10 12
T
A
= 25°C