LTC3707 Datasheet, PDF (4/32 Pages) Linear Technology – High Effi ciency, 2-Phase Synchronous Step-Down Switching Regulator

LTC3707
ELECTRICAL CHARACTERISTICS ^{The l denotes the specifications which apply over the full operating}
temperature range, otherwise specifications are at T_A = 25°C. V_IN = 15V, V_{RUN/SS1, 2} = 5V unless otherwise noted.
SYMBOL
PARAMETER
f_HIGH
Highest Frequency
I_FREQSET
FREQSET Input Current
3.3V Linear Regulator
V_3.3OUT
3.3V Regulator Output Voltage
V_3.3IL
3.3V Regulator Load Regulation
V_3.3VL
3.3V Regulator Line Regulation
PGOOD Output
V_PGL
I_PGOOD
V_PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level, Either Controller
CONDITIONS
V_FREQSET = 2.4V
V_FREQSET = 0V
No Load
I_3.3 = 0 to 10mA
6V < V_IN < 30V
I_PGOOD = 2mA
V_PGOOD = 5V
V_OSENSE Respect to Set Output Voltage
V_OSENSE Ramping Negative
V_OSENSE Ramping Positive
MIN TYP MAX UNITS
280 310 360 kHz
–2 –1 μA
l 3.20 3.35 3.45
V
0.5
2
%
0.05 0.2
%
0.1 0.3
V
1
μA
–6
–7.5 –9.5 %
6
7.5 9.5 %
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 LTC3707E 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 LTC3707I 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 P_D according to the following formula:
LTC3707EGN = T_J = T_A + (P_D • 85°C/W)
Note 4: The LTC3707 is tested in a feedback loop that servos V_{ITH1, 2} to a
specified voltage and measures the resultant V_{OSENSE1, 2.}
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 IC minimum on-time is tested under an ideal condition
without external power FETs. It can be different when the IC is working in
an actual circuit. See Minimum On-Time Considerations in the Application
Information section.
Note 8: V_FREQSET pin internally tied to a 1.19V reference through a
large resistance.
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Output Current
and Mode (Figure 13)
100
Burst Mode
90 OPERATION
80
70
FORCED
60
CONTINUOUS
MODE (PWM)
50
40
CONSTANT
FREQUENCY
30
(BURST DISABLE)
20
10
0
0.001
V_IN = 15V
V_OUT = 5V
0.01
0.1
1
10
OUTPUT CURRENT (A)
3707 G01
Efficiency vs Output Current
(Figure 13)
100
V_IN = 15V
V_OUT = 5V
V_IN = 7V
90
V_IN = 10V
80
V_IN = 15V
V_IN = 20V
70
60
50
0.001
0.01
0.1
1
OUTPUT CURRENT (A)
10
3707 G02
4
Efficiency vs Input Voltage
(Figure 13)
100
90
80
70
60
V_OUT = 5V
I_OUT = 3A
50
5
15
25
30
INPUT VOLTAGE (V)
3707 G03
3707fb