LTC3855_15 Datasheet, PDF (7/44 Pages) Linear Technology – Dual, Multiphase Synchronous DC/DC Controller with Differential Remote Sense

Typical Performance Characteristics
LTC3855
Tracking Up and Down
with External Ramp
TK/SS1
TK/SS2
2V/DIV
V_OUT1
V_OUT1
V_OUT2
500mA/DIV
V_OUT2
10ms/DIV
V_IN = 12V
V_OUT1 = 1.8V, 1.5Ω LOAD
V_OUT2 = 1.2V, 1Ω LOAD
3855 G07
Quiescent Current
vs Temperature without EXTV_CC
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3855 G08
INTV_CC Line Regulation
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
0
10
20
30
INPUT VOLTAGE (V)
40
3855 G09
Current Sense Threshold
vs I_TH Voltage
80
I_LIM = INTV_CC
60
40
I_LIM = FLOAT
20
I_LIM = GND
0
–20
–40
0
0.5
1
1.5
2
V_ITH (V)
3855 G10
Maximum Current Sense
Threshold vs Common Mode
Voltage
80
70
I_LIM = INTV_CC
60
50
I_LIM = FLOAT
40
30
I_LIM = GND
20
10
0
0
2
4
6
8 10 12
V_SENSE COMMON MODE VOLTAGE (V)
3855 G11
Maximum Current Sense
Threshold vs Duty Cycle
80
70
I_LIM = INTV_CC
60
50
I_LIM = FLOAT
40
30
I_LIM = GND
20
10
0
0
20
40
60
80 100
DUTY CYCLE (%)
3855 G12
Maximum Current Sense Voltage
vs Feedback Voltage (Current
Foldback)
90
80
I_LIM = INTV_CC
TK/SS Pull-Up Current
vs Temperature
1.6
70
60
I_LIM = FLOAT
1.4
50
40
I_LIM = GND
30
1.2
20
10
0
0 0.1 0.2 0.3 0.4 0.5 0.6
FEEDBACK VOLTAGE (V)
3855 G13
1.0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3855 G14
3855f