LTC3878_15 Datasheet, PDF (5/26 Pages) Linear Technology – Fast, Wide Operating Range No RSENSE Step-Down DC/DC Controller

Typical Performance Characteristics
LTC3878
Frequency vs Load Current
410
CONTINUOUS MODE
370
330
DISCONTINUOUS MODE
290
250
210
170
130
90
V_IN = 15V
50
V_OUT = 1.2V
FIGURE 7 CIRCUIT
10
0 2 4 6 8 10 12 14
I_LOAD (A)
3878 G10
Current Sense Voltage
vs I_TH Voltage
300
250
200
150
100
50
0
–50
–100
–150
0
V_RNG = 0.2V
V_RNG = 0.5V
V_RNG = 1.0V
V_RNG = 1.5V
V_RNG = 2.0V
0.5
1
1.5
2
2.5
I_TH VOLTAGE (V)
3878 G13
Maximum V_DS Current Sense
Threshold vs V_RNG Voltage
300
250
200
150
100
50
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
V_RNG VOLTAGE (V)
3878 G16
Load Regulation FCM
0
–0.02
–0.04
V_IN = 15V
V_OUT = 1.2V
FIGURE 7 CIRCUIT
–0.06
–0.08
–0.10
–0.12
–0.14
–0.16
0
5
10
LOAD CURRENT (A)
15
3878 G11
On-Time vs I_ON Current
10000
FIGURE 7 CIRCUIT
1000
100
10
1
10
I_ON CURRENT (µA)
100
3878 G14
Maximum V_DS Current Sense
Threshold vs RUN/SS Voltage
140
120
100
80
60
40
20
0
1.5
2.0
2.5
3.0
RUN/SS VOLTAGE (V)
3878 G17
I_TH Voltage vs Load Current
2.5
2.3
2.1
1.9
1.7
1.5
1.3
1.1
V_IN = 15V
V_OUT = 1.2V
0.9
FIGURE 7 CIRCUIT
0.7
CONTINUOUS MODE
DISCONTINUOUS MODE
0.5
0
5
10
15
20
25
LOAD CURRENT (A)
3878 G12
Current Limit Foldback
140
V_RNG = 1V
FIGURE 7 CIRCUIT
120
100
80
60
40
20
0
0
0.2
0.4
0.6
0.8
V_FB (V)
3878 G15
Feedback Reference Voltage vs
Temperature
0.808
0.806
0.804
0.802
0.800
0.798
0.796
0.794
0.792
–50 –30 –10 10 30 50 70 90 110
TEMPERATURE (°C)
3878 G18
3878fa