Datasheet

LTC3854
4
3854fb
ELECTRICAL CHARACTERISTICS
Efficiency vs Output Current Efficiency vs Input Voltage
5A Load Step V
OUT
= 5V, V
IN
= 24V
Top Gate and Bottom Gate in
Forced Continuous Mode
Top Gate and Bottom Gate in
Dropout
LOAD CURRENT (A)
1
EFFICIENCY (%)
100
90
92
94
96
98
88
86
53 7 8 9
3854 G01
1042 6
V
IN
= 12V
V
IN
= 24V
V
IN
= 32V
V
IN
= 6V
(SEE FIGURE 9)
V
OUT
= 5V
V
IN
(V)
5
EFFICIENCY (%)
99
96
94
97
98
95
93
2515 35
3854 G02
402010 30
V
OUT
= 5V
(SEE FIGURE 9)
I
OUT
= 10A
I
OUT
= 5A
5V
OUT
200mV/DIV
5A/DIV
LOAD STEP
I
LOAD
10A/DIV
50µs/DIV
3854 G03
BG
TG
4µs/DIV
3854 G04
BG
TG
4µs/DIV
3854 G05
TYPICAL PERFORMANCE CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
The LTC3854E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls. The LTC3854I is guaranteed to meet
performance specifications over the full –40°C to 85°C operating
temperature range.
Note 3: T
J
is calculated from the ambient temperature T
A
and power
dissipation PD according to the following formulas:
LTC3854DDB: T
J
= T
A
+ (P
D
• 76°C/W)
LTC3854MSE: T
J
= T
A
+ (P
D
• 40°C/W)
Note 4: The LTC3854 is tested in a feedback loop that servos V
ITH
to a
specified 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. Not 100% tested in production.
Note 7:
The minimum on-time condition is specified for an inductor peak-
to-peak ripple current 40% of I
MAX
(see Minimum On-Time Considerations
in the Applications Information section).
Note 8: The LTC3854 maximum LDO current specification assumes there
is no external DC load current being pulled from INTV
CC
pin.