Datasheet

LT3975
7
3975f
SS Pin Current
TYPICAL PERFORMANCE CHARACTERISTICS
Start-Up/Dropout Performance Start-Up/Dropout Performance
Boost Capacitor Charger Boost Diode Forward Voltage
Dropout Comparator Thresholds
Burst Mode Switching Waveforms Dropout Switching Waveforms
Full Frequency Switching
Waveforms
T
A
= 25°C, unless otherwise noted.
TEMPERATURE (°C)
–55
SS PIN CURRENT (µA)
2.4
35
3975 G28
1.8
1.4
–25 5 65
1.2
1.0
2.6
2.2
2.0
1.6
95 125 155
V
SS
= 0.5V
OUT PIN VOLTAGE (V)
0
OUT PIN CURRENT (mA)
80
120
16
3975 G29
40
0
4
8
12
2
6
10
14
160
60
100
20
140
V
BST
= V
IN
BOOST DIODE CURRENT (A)
0
BOOST DIODE VOLTAGE (V)
0.8
1.0
1.2
2
3975 G30
0.6
0.4
0
0.5
1
1.5
0.2
1.6
1.4
TEMPERATURE (°C)
–55
400
DROPOUT THRESHOLD (mV)
420
460
480
500
600
540
5
65
95 125
3975 G31
440
560
580
520
–25
35
155
V
OUT
RISING
V
OUT
FALLING
V
IN
1V/DIV
V
OUT
1V/DIV
V
OUT
V
IN
100ms/DIV2.5Ω LOAD
(2A IN REGULATION)
3975 G32
V
IN
1V/DIV
V
OUT
1V/DIV
V
OUT
V
IN
100ms/DIV1kΩ LOAD
(5mA IN REGULATION)
3975 G33
V
SW
5V/DIV
V
OUT
10mV/DIV
I
L
0.5A/DIV
5µs/DIVV
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 20mA
C
OUT
= 47µF
3975 G34
V
SW
5V/DIV
V
OUT
20mV/DIV
I
L
1A/DIV
1µs/DIVV
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 1A
C
OUT
= 47µF
3975 G35
V
SW
2V/DIV
V
OUT
50mV/DIV
I
L
1A/DIV
5µs/DIVV
IN
= 5V
V
OUT
SET FOR 5V
I
LOAD
= 0.5A
C
OUT
= 47µF
3975 G36