Download LT3957 - Linear Technology

LT3957
TYPICAL PERFORMANCE CHARACTERISTICS
Dynamic Quiescent Current
vs Switching Frequency
TA ≈ TJ = 25°C, unless otherwise noted.
Normalized Switching
Frequency vs FBX
RT vs Switching Frequency
120
1000
12
NORMALIZED FREQUENCY (%)
10
RT (kΩ)
IQ(mA)
8
6
100
4
2
10
0
100 200 300 400 500 600 700 800 900 1000
SWITCHING FREQUENCY (kHz)
40
20
310
305
300
295
290
285
0
0.4
0.8
FBX VOLTAGE (V)
1.2
1.6
SW Pin Current Limit
vs Duty Cycle
6.6
6.6
6.4
6.4
SW PIN CURRENT LIMIT (A)
RT = 41.2k
315
–0.4
3957 G06
SW Pin Current Limit
vs Temperature
SW PIN CURRENT LIMIT (A)
SWITCHING FREQUENCY (kHz)
60
3957 G05
Switching Frequency
vs Temperature
320
80
0
–0.8
0 100 200 300 400 500 600 700 800 900 1000
SWITCHING FREQUENCY (kHz)
3957 G04
325
100
6.2
6.0
5.8
5.6
6.2
6.0
5.8
5.6
280
275
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
5.4
–50
125
5.4
–25
50
25
0
75
TEMPERATURE (°C)
100
EN/UVLO Threshold
vs Temperature
1.24
EN/UVLO FALLING
40
2.4
30
2.2
20
10
0
50
25
0
75
TEMPERATURE (°C)
100
125
3957 G10
80
100
2.0
1.8
1.20
–25
40
60
DUTY CYCLE (%)
EN/UVLO Hysteresis Current
vs Temperature
IEN/UVLO (μA)
EN/UVLO CURRENT (μA)
EN/UVLO VOLTAGE (V)
1.26
EN/UVLO RISING
20
3957 G09
EN/UVLO Current vs Voltage
1.28
1.18
–50
0
3957 G08
3957 G07
1.22
125
0
10
20
30
EN/UVLO VOLTAGE (V)
40
3957 G11
1.6
–50
–25
50
25
0
75
TEMPERATURE (°C)
100
125
3957 G12
3957f
5