Datasheet

LTC3851A
6
3851afa
Typical perForMance characTerisTics
Maximum Current Sense Threshold
vs Common Mode Voltage
Maximum Peak Current Sense
Threshold vs I
TH
Voltage
Burst Mode Peak Current Sense
Threshold vs I
TH
Voltage
Maximum Current Sense
Threshold vs Duty Cycle
INTV
CC
Line Regulation
Maximum Current Sense
Threshold vs Feedback Voltage
(Current Foldback)
TK/SS Pull-Up Current
vs Temperature
INPUT VOLTAGE (V)
4 8 12
3.5
INTV
CC
VOLTAGE (V)
3.7
4.1
4.3
4.5
28 32 36
5.3
3851A G13
3.9
16 20 24 40
4.7
4.9
5.1
I
LOAD
= 0mA
I
LOAD
= 25mA
V
SENSE
COMMON MODE VOLTAGE (V)
0
0
V
SENSE
THRESHOLD (mV)
3 3.5 4 4.5
90
80
70
60
50
40
30
20
10
3851A G14
0.5 1 1.5 2 2.5 5
I
LIM
= INTV
CC
I
LIM
= FLOAT
I
LIM
= GND
V
ITH
(V)
0 0.2 0.4 0.6
V
SENSE
(mV)
0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2
3851A G15
2.4
90
80
70
60
50
40
30
20
10
0
–10
–20
DUTY CYCLE RANGE: 0% TO 100%
I
LIM
= INTV
CC
I
LIM
= FLOAT
I
LIM
= GND
V
ITH
(V)
V
SENSE
(mV)
60
50
40
30
20
10
0
0.8 1.2 1.6 2.0
3851A G16
2.40.60.4 1.0 1.4 1.8 2.2
I
LIM
= FLOAT
BURST COMPARATOR FALLING THESHOLD:
V
ITH
= 0.4V
MAXIMUIM
MINIMUIM
FEEDBACK VOLTAGE (V)
0
MAXIMUM V
SENSE
(mV)
0.8
3851A G18
0
0.2
0.4
0.6
0.1
0.3
0.5
0.7
90
80
70
60
50
40
30
20
10
I
LIM
= INTV
CC
I
LIM
= FLOAT
I
LIM
= GND
TEMPERATURE (°C)
–75
0.5
TK/SS CURRENT (µA)
0.6
0.8
0.9
1.0
1.5
1.2
0
50
75
3851A G19
0.7
1.3
1.4
1.1
–25–50
25
100 125
150
DUTY CYCLE (%)
0
0
CURRENT SENSE THRESHOLD (mV)
10
30
40
50
40
80
100
90
3851A G17
20
20 60
60
70
80
I
LIM
= INTV
CC
I
LIM
= FLOAT
I
LIM
= GND
Ratiometric Tracking with Master
Supply
Input DC Supply Current
vs Input Voltage
V
MASTER
0.5V/DIV
V
OUT
2A LOAD
0.5V/DIV
10ms/DIV
3851A G11
INPUT VOLTAGE (V)
4
SUPPLY CURRENT (mA)
12
20
24 40
3851A G12
8 16
28
32
36
3.0
2.5
2.0
1.5
1.0
0.5
0