Datasheet

LT3995
7
3995f
For more information www.linear.com/LT3995
SS Pin Current
Dropout Comparator Thresholds
Boost Capacitor Charger
Dropout Performance
Boost Diode Forward Voltage
Burst Mode Switching Waveforms
Full Frequency Switching
Waveforms
Dropout Switching
Waveforms
TYPICAL PERFORMANCE CHARACTERISTICS
Burst Frequency
T
A
= 25°C, unless otherwise noted.
LOAD CURRENT (mA)
0
50
SWITCHING FREQUENCY (kHz)
100
200
300
400
600
20
40 60 80
3995 G27
100 120
500
V
OUT
= 5V
f
SW
= 500kHz
L = 10µH
V
OUT
= 3.3V
f
SW
= 300kHz
L = 8.2µH
V
IN
= 12V
TEMPERATURE (°C)
–55
SS PIN CURRENT (µA)
2.4
35
3995 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
3995 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)
1.0
1.2
1.4
2
3995 G30
0.8
0.6
0.4
0
0.5
1
1.5
0.2
1.8
1.6
TEMPERATURE (°C)
–55
400
DROPOUT THRESHOLD (mV)
420
460
480
500
600
540
5
65
95 125
3995 G31
440
560
580
520
–25
35
155
V
OUT
RISING
V
OUT
FALLING
V
IN
2V/DIV
V
IN
V
OUT
V
OUT
2V/DIV
100ms/DIV1kΩ LOAD
(12mA IN REGULATION)
3995 G32
V
SW
20V/DIV
V
OUT
50mV/DIV
I
L
1A/DIV
5µs/DIVV
IN
= 48V
V
OUT
= 3.3V
I
LOAD
= 70mA
C
OUT
= 47µF
3995 G33
V
SW
20V/DIV
V
OUT
50mV/DIV
I
L
1A/DIV
2µs/DIVV
IN
= 48V
V
OUT
= 3.3V
I
LOAD
= 1A
C
OUT
= 47µF
3995 G34
V
SW
2V/DIV
V
OUT
50mV/DIV
I
L
1A/DIV
5µs/DIVV
IN
= 5V
V
OUT
SET FOR 5V
I
LOAD
= 0.3A
C
OUT
= 47µF
3995 G35