Datasheet

LTC3857-1
6
38571fc
TYPICAL PERFORMANCE CHARACTERISTICS
Total Input Supply Current
vs Input Voltage
EXTV
CC
Switchover and INTV
CC
Voltages vs Temperature
INTV
CC
Line Regulation
Maximum Current Sense Voltage
vs I
TH
Voltage
SENSE
–
Pin Input Bias Current
Maximum Current Sense
Threshold vs Duty Cycle
Foldback Current Limit
Quiescent Current vs Temperature
INTV
CC
and EXTV
CC
vs Load Current
INPUT VOLTAGE (V)
5
0
SUPPLY CURRENT (µA)
50
150
200
250
500
350
15
25
30
38571 G10
100
400
450
300
10
20
35
40
NO LOAD
300µA
500µA
V
OUT1
= 3.3V
RUN2 = 0V
FIGURE 13 CIRCUIT
TEMPERATURE (°C)
–45
4.0
EXTV
CC
AND INTV
CC
VOLTAGE (V)
4.2
4.6
4.8
5.0
6.0
5.4
5
55
80
38571 G11
4.4
5.6
5.8
5.2
–20
30
105
130
INTV
CC
EXTV
CC
RISING
EXTV
CC
FALLING
V
SENSE
COMMON MODE VOLTAGE (V)
0
–600
SENSE
–
CURRENT (µA)
–500
–400
–300
–200
0
5
10 15 20
38571 G14
25
–100
–550
–450
–350
–250
–50
–150
TEMPERATURE (°C)
–45
QUIESCENT CURRENT (µA)
75
30
38571 G17
60
50
–20 5 55
45
40
80
70
65
55
80 105 130
LOAD CURRENT (mA)
0
INV
CC
VOLTAGE (V)
5.10
5.15
5.20
160
38571 G18
5.05
5.00
4.95
20 40 60
80 100
120 140 180
200
EXTV
CC
= 0V
EXTV
CC
= 8.5V
V
IN
= 12V
INPUT VOLTAGE (V)
0
INTV
CC
VOLTAGE (v)
5.0
5.1
40
38571 G12
4.9
4.8
10
20
30
5
15
25
35
5.2
V
ITH
(V)
0
CURRENT SENSE THESHOLD (mV)
40
60
80
0.6 1.0
38571 G13
20
0
0.2 0.4
0.8 1.2 1.4
–20
–40
Burst Mode
OPERATION
PULSE-SKIPPING MODE
5% DUTY CYCLE
FORCED CONTINUOUS MODE
DUTY CYCLE (%)
0
MAXIMUM CURRENT SENSE VOLTAGE (mV)
40
60
80
38571 G15
20
0
20
40
50
100
80
60
10
30
90
70
FEEDBACK VOLTAGE (V)
0
0
MAXIMUM CURRENT SENSE VOLTAGE (mV)
10
30
40
50
0.6
90
38571 G16
20
0.3
0.1
0.7
0.4
0.2
0.8
0.5 0.9
60
70
80