Datasheet

LTC3835-1
4
38351fc
ELECTRICAL CHARACTERISTICS
Note 3: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LTC3835GN-1: T
J
= T
A
+ (P
D
• 90°C/W)
LTC3835EDHC-1: T
J
= T
A
+ (P
D
• 43.5°C/W)
Note 4: The LTC3835-1 is tested in a feedback loop that servos V
ITH
to a
specifi ed voltage and measures the resultant V
FB
.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 7: The minimum on-time condition is specifi ed for an inductor
peak-to-peak ripple current ≥40% of I
MAX
(see Minimum On-Time
Considerations in the Applications Information section).
TYPICAL PERFORMANCE CHARACTERISTICS
Effi ciency and Power Loss
vs Output Current
Effi ciency vs Load Current Effi ciency vs Input Voltage
Load Step
(Burst Mode Operation)
Load Step
(Pulse-Skipping Mode)
LOAD CURRENT (mA)
EFFICIENCY (%)
POWER LOSS (mW)
0.01 0.1 1 10 100 1000 10000
38351 G01
0.001
1
10
1000
100
0.1
10000
40
50
60
70
80
30
20
10
0
90
100
Burst Mode OPERATION
FORCED CONTINUOUS MODE
PULSE SKIPPING MODE
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 10 CIRCUIT
LOAD CURRENT (mA)
EFFICIENCY (%)
0.01 0.1 1 10 100 1000 10000
38351 G02
0.001
50
60
70
80
40
90
100
V
IN
= 12V
V
IN
= 5V
V
OUT
= 3.3V
FIGURE 10 CIRCUIT
INPUT VOLTAGE (V)
EFFICIENCY (%)
5 101520 30 40
38351 G03
0
25 35
86
88
90
92
94
84
82
96
98
V
OUT
= 3.3V
FIGURE 10 CIRCUIT
20μs/DIV
V
OUT
100mV/DIV
AC
COUPLED
I
L
2A/DIV
38351 G0
4
Load Step
(Forced Continuous Mode)
20μs/DIV
V
OUT
100mV/DIV
AC
COUPLED
I
L
2A/DIV
38351 G05
20ms/DIV
V
OUT
100mV/DIV
AC
COUPLED
I
L
2A/DIV
38351 G06
FIGURE 10 CIRCUIT
V
OUT
= 3.3V
FIGURE 10 CIRCUIT
V
OUT
= 3.3V
FIGURE 10 CIRCUIT
V
OUT
= 3.3V
T
A
= 25°C, unless otherwise noted.