Datasheet

LT3957A
5
3957afa
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
≈ T
J
= 25°C, unless otherwise noted.
Dynamic Quiescent Current
vs Switching Frequency
R
T
vs Switching Frequency
Normalized Switching
Frequency vs FBX
SWITCHING FREQUENCY (kHz)
100
0
I
Q
(mA)
4
6
12
300
500 600
700
2
8
10
200
400
900800
1000
3957A G04
SWITCHING FREQUENCY (kHz)
0
10
R
T
(k)
100
1000
300
500 600
700
100 200
400
900800
1000
3957A G05
FBX VOLTAGE (V)
–0.8
0
NORMALIZED FREQUENCY (%)
20
40
60
80
120
–0.4
0 0.4 0.8
3957A G06
1.2 1.6
100
Switching Frequency
vs Temperature
SW Pin Current Limit
vs Temperature
TEMPERATURE (°C)
–50
275
SWITCHING FREQUENCY (kHz)
280
285
290
295
300
305
310
325
–25
025 7550
3957A G07
100 125
315
320
R
T
= 41.2k
TEMPERATURE (°C)
–50
5.4
SW PIN CURRENT LIMIT (A)
6.0
5.8
6.2
6.4
6.6
0
50
75
5.6
–25
25
100
125
3957A G08
SW Pin Current Limit
vs Duty Cycle
DUTY CYCLE (%)
0
5.4
5.6
5.8
SW PIN CURRENT LIMIT (A)
6.2
20 40 8060
6.6
6.0
6.4
100
3957A G09
EN/UVLO Threshold
vs Temperature
EN/UVLO Current vs Voltage
EN/UVLO Hysteresis Current
vs Temperature
TEMPERATURE (°C)
–50
1.18
1.22
1.24
1.28
0
50
75
1.20
–25
25
100
125
1.26
3957A G10
EN/UVLO VOLTAGE (V)
EN/UVLO RISING
EN/UVLO FALLING
EN/UVLO VOLTAGE (V)
0
0
EN/UVLO CURRENT (µA)
20
10 3020
40
10
30
40
3957A G11
TEMPERATURE (°C)
–50
1.6
I
EN/UVLO
(µA)
1.8
2.0
2.2
2.4
0
50
75
–25
25
100
125
3957A G12