LTC3851 LINER [Linear Technology], LTC3851 Datasheet - Page 4

• Manufacturer Part Number: LTC3851
• Description: Synchronous Step-Down Switching Regulator Controller
• Manufacturer: LINER [Linear Technology]

LTC3851
ELECTRICAL CHARACTERISTICS
SYMBOL
Oscillator and Phase-Locked Loop
f
f
f
R
I
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 LTC3851E 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.
Note 3: T
dissipation P
TYPICAL PERFORMANCE CHARACTERISTICS
4
temperature range, otherwise specifi cations are at T
NOM
LOW
HIGH
FREQ
MODE/PLLIN
LTC3851EGN: T
LTC3851EUD: T
100
90
80
70
60
50
40
30
20
10
0
10
Effi ciency vs Output Current and
Mode (Figure TBD)
V
V
J
IN
OUT
is calculated from the ambient temperature T
BURST
= 12V
D
= 1.2V
according to the following formulas:
PARAMETER
Nominal Frequency
Lowest Frequency
Highest Frequency
MODE/PLLIN Input Resistance
Phase Detector Output Current
PULSE
Sinking Capability
Sourcing Capability
SKIP
LOAD CURRENT (mA)
J
J
100
= T
= T
A
A
CCM
+ (P
+ (P
D
D
• 90°C/W)
• 68°C/W)
1000
3851 G01
10000
A
100
and power
90
80
70
60
40
20
10
50
30
CONDITIONS
R
R
R
f
f
0
MODE
MODE
10
FREQ
FREQ
FREQ
Effi ciency vs Output Current
and Mode
A
= 25°C. V
PULSE
> f
< f
= 60k
= 160k
= 36k
SKIP
OSC
OSC
The
BURST
LOAD CURRENT (mA)
100
l
IN
CCM
denotes the specifi cations which apply over the full operating
= 15V, V
Note 4: The LTC3851 is tested in a feedback loop that servos V
specified voltage and measures the resultant V
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 specified for an inductor
peak-to-peak ripple current ~40% of I
Considerations in the Applications Information section).
V
V
FIGURE 11 CIRCUIT
IN
OUT
1000
RUN
= 12V
= 3.3V
= 5V unless otherwise noted.
3851 G02
10000
100
90
80
70
60
50
40
30
20
10
0
10
Effi ciency vs Output Current and
Mode (Figure TBD)
V
V
IN
OUT
MIN
PULSE
480
220
710
= 12V
SKIP
MAX
= 5V
BURST
(see Minimum On-Time
LOAD CURRENT (mA)
100
FB
TYP
500
250
750
100
–10
.
10
CCM
1000
MAX
530
280
790
ITH
to a
3851 G03
UNITS
10000
3851f
kHz
kHz
kHz
kΩ
μA
μA