LTC3892_15 Datasheet, PDF (8/36 Pages) Linear Technology – 60V Low IQ, Dual, 2-Phase Synchronous Step-Down DC/DC Controller

LTC3892/LTC3892-1
Typical Performance Characteristics
DRV_CC and EXTV_CC
vs Load Current
6.4
6.2
EXTV_CC = 0V
6
5.8
EXTV_CC = 8.5V
5.6
5.4
5.2
5
4.8
EXTV_CC = 5V
4.6
4.4
4.2
V_BIAS = 12V
DRVSET = GND
4
0 25 50
75 100
LOAD CURRENT (mA)
125 150
3892 G10
SENSE Pins Total Input Current
vs V_SENSE Voltage
800
700
600
500
400
300
200
100
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65
V_SENSE COMMON MODE VOLTAGE (V)
3892 G13
Maximum Current Sense
Threshold vs Duty Cycle
100
90
80
70
60
50
40
30
20
I_LIM = INTV_CC
10
I_LIM = FLOAT
I_LIM = GND
0
0 10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
3892 G16
EXTV_CC Switchover and DRV_CC
Voltages vs Temperature
11
DRV_CC (DRVSET = INTV_CC)
10
9
8
EXTV_CC RISING
DRVUV = INTV_CC
7
EXTV_CC FALLING
6
DRV_CC (DRVSET = 0V)
5
EXTV_CC RISING
DRVUV = GND
4
EXTV_CC FALLING
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3892 G11
SENSE^– Pin Input Bias Current vs
Temperature
900
800
V_OUT > INTV_CC + 0.5V
700
600
500
400
300
200
100
V_OUT < INTV_CC – 0.5V
0
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3892 G14
Maximum Current Sense
Threshold vs I_TH Voltage
100
5% DUTY CYCLE
80
PULSE-SKIPPING
60
Burst Mode
OPERATION
40
20
0
–20
–40
0
I_LIM = INTV_CC
I_LIM = FLOAT
I_LIM = GND
FORCED CONTINUOUS MODE
0.2 0.4 0.6 0.8 1 1.2 1.4
V_ITH (V)
3892 G17
8
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Undervoltage Lockout
Threshold vs Temperature
8
RISING
7.5
7
DRVUV = INTV_CC
6.5
FALLING
6
5.5
5
4.5
RISING
4
3.5
FALLING
DRVUV = GND
3
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3892 G12
Foldback Current Limit
100
90
80
70
60
50
40
30
20
I_LIM = INTV_CC
10
I_LIM = FLOAT
I_LIM = GND
0
0 100 200 300 400 500 600 700 800
FEEDBACK VOLTAGE (mV)
3892 G15
Shutdown (RUN) Threshold
vs Temperature
1.4
1.35
1.3
RISING
1.25
1.2
FALLING
1.15
1.1
1.05
1
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3892 G18
38921f