ltc3850gn-2 Linear Technology Corporation, ltc3850gn-2 Datasheet - Page 4

• Manufacturer Part Number: ltc3850gn-2
• Description: Dual, 2-phase Synchronous Step-down Switching Controller
• Manufacturer: Linear Technology Corporation

LTC3850-2
ELECTRICAL CHARACTERISTICS
SYMBOL
Oscillator and Phase-Locked Loop
f
f
f
R
I
PGOOD Output
V
I
V
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 LTC3850I-2 is guaranteed to meet performance specifi cations
over the –40°C to 85°C operating temperature range.
Note 3: T
dissipation P
TYPICAL PERFORMANCE CHARACTERISTICS
4
temperature range, otherwise specifi cations are at T
NOM
LOW
HIGH
FREQ
PGOOD
PGL
PG
MODE/PLLIN
LTC3850IGN-2: T
100
90
80
70
60
40
20
10
50
30
0
10
Effi ciency vs Output Current
and Mode
CIRCUIT OF FIGURE 14
V
V
CCM
J
IN
OUT
is calculated from the ambient temperature T
= 12V
D
= 1.8V
according to the following formulas:
DCM
PARAMETER
Nominal Frequency
Lowest Frequency
Highest Frequency
MODE/PLLIN Input Resistance
Phase Detector Output Current
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
Sinking Capability
Sourcing Capability
LOAD CURRENT (mA)
100
J
= T
A
+ (P
D
1000
• 95°C/W)
BURST
10000
38502 G01
100
90
80
70
60
50
40
30
20
10
0
A
10
and power
CIRCUIT OF FIGURE 14
CONDITIONS
V
V
V
f
f
I
V
V
Effi ciency vs Output Current
and Mode
MODE
MODE
PGOOD
FREQ
FREQ
FREQ
PGOOD
FB
V
V
A
with Respect to Set Regulated Voltage
FB
FB
DCM
= 25°C, V
CCM
= 1.2V
= 0V
≥ 2.4V
< f
> f
Ramping Negative
Ramping Positive
BURST
= 2mA
= 5V
OSC
OSC
The
LOAD CURRENT (mA)
100
l
IN
denotes the specifi cations which apply over the full operating
= 15V, V
Note 4: The LTC3850I-2 is tested in a feedback loop that servos V
a specifi ed 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 specifi ed for an inductor
peak-to-peak ripple current ≥40% of I
Considerations in the Applications Information section).
1000
RUN1,2
V
V
IN
OUT
= 12V
= 3.3V
= 5V, unless otherwise noted.
38502 G02
10000
100
95
90
85
80
Effi ciency and Power Loss
vs Input Voltage
5
CIRCUIT OF FIGURE 14
V
I
OUT
OUT
= 2A
= 3.3V
MIN
10
450
210
700
–5
MAX
5
INPUT VOLTAGE (V)
EFFICIENCY
POWER LOSS
(see Minimum On-Time
15
– 7.5
TYP
500
250
780
250
–13
0.1
7.5
13
FB1,2
.
20
MAX
550
290
860
–10
0.3
±2
10
38502 G03
ITH1,2
25
2000
1500
1000
500
0
UNITS
38502f
kHz
kHz
kHz
to
kΩ
μA
μA
μA
%
%
V