LTC3859_15 Datasheet, PDF (9/42 Pages) Linear Technology – Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller

TYPICAL PERFORMANCE CHARACTERISTICS
LTC3859
INTV_CC Line Regulation
5.5
5.4
5.3
5.2
5.1
5.0
0
5 10 15 20 25 30 35 40
INPUT VOLTAGE (V)
3859 G19
SENSE Pins Total Input Current
vs V_SENSE Voltage
800
700
SENSE1, 2 PINS
600
500
400
300
200
SENSE3 PIN
100
0
0 5 10 15 20 25 30 35 40
V_SENSE COMMON MODE VOLTAGE (V)
3859 G22
Maximum Current Sense
Threshold vs Duty Cycle
80
70
60
50
BUCK
40
BOOST
30
20
10
0
0 10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
3859 G25
INTV_CC and EXTV_CC
vs Load Current
5.50
V_BIAS = 12V
5.45
5.40
EXTV_CC = 0V
5.35 ^EXTVCC ^{= 8.5V}
5.30
5.25
5.20
5.15
0
20 40 60 80 100 120 140 160 180 200
LOAD CURRENT (mA)
3859 G20
Buck SENSE Pins Total Input
Current vs Temperature
900
800
V_OUT = 28V
700
600
500
400
300
200
100
0
–45 –20
V_OUT = 3.3V
5 30 35 55 80
TEMPERATURE (°C)
105 130
3859 G23
Maximum Current Sense
Threshold vs I_TH Voltage
60
50
40
30
20
10
0
–10
–20
–30
0
PULSE-SKIPPING
FORCED CONTINUOUS
Burst Mode OPERATION
0.2 0.4 0.6 0.8 1 1.2 1.4
I_TH (V)
3859 G26
EXTV_CC Switchover and INTV_CC
Voltages vs Temperature
6.0
5.8
5.6
INTV_CC
5.4
5.2
5.0
4.8
EXTV_CC RISING
4.6
4.4
EXTV_CC FALLING
4.2
4.0
–45 –20
5 30 55 80
TEMPERATURE (°C)
105 130
3859 G21
Boost SENSE Pin Total Input
Current vs Temperature
200
180
SENSE3⁺ PIN
160
140
120
100
80
60
40
20
0
–45 –20
SENSE3^– PIN
5 30 35 55 80 105 130
TEMPERATURE (°C)
3859 G24
Soft-Start Pull-Up Current
vs Temperature
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
–45 –20
5 30 55 80
TEMPERATURE (°C)
105 130
3859 G27
3859fa
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