LTC3727-1_15 Datasheet, PDF (4/32 Pages) Linear Technology – High Efficiency, 2-Phase Synchronous Step-Down Switching Regulators

LTC3727/LTC3727-1
ELECTRICAL CHARACTERISTICS The ● 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
R_PLLIN
I_PLLFLTR
PARAMETER
PLLIN Input Resistance
Phase Detector Output Current
Sinking Capability
CONDITIONS
f_PLLIN < f_OSC
MIN TYP MAX UNITS
50
kΩ
–15
μA
Sourcing Capability
3.3V Linear Regulator
V_3.3OUT
V_3.3IL
V_3.3VL
3.3V Regulator Output Voltage
3.3V Regulator Load Regulation
3.3V Regulator Line Regulation
PGOOD Output
V_PGL
I_PGOOD
V_PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level, Either Controller
f_PLLIN > f_OSC
No Load
I_3.3 = 0mA to 10mA
6V < V_IN < 30V (LTC3727)
6V < V_IN < 30V (LTC3727-1)
I_PGOOD = 2mA
V_PGOOD = 5V
V_OSENSE with Respect to Set Output Voltage
V_OSENSE Ramping Negative
V_OSENSE Ramping Positive
15
μA
● 3.25 3.35 3.45
V
0.5
2.5
%
0.05
0.2
%
0.05
0.3
%
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 LTC3727E/LTC3727E-1 are 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 LTC3727IG-1 is
guaranteed to meet performance specifications over the –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 formulas:
LTC3727EG/LTC3727EG-1/LTC3727IG-1: T_J = T_A + (P_D • 95 °C/W)
LTC3727EUH-1: T_J = T_A + (P_D • 34 °C/W)
Note 4: The LTC3727/LTC3727-1 are 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 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).
TYPICAL PERFOR A CE CHARACTERISTICS
Efficiency vs Output Current
and Mode (Figure 13)
100
Burst Mode
90 _OPERATION
80
70
FORCED
CONTINUOUS
MODE
60
50
40
CONSTANT
FREQUENCY
30
(BURST DISABLE)
20
10
0
0.001
V_IN = 15V
V_OUT = 8.5V
0.01
0.1
1
10
OUTPUT CURRENT (A)
3727 G01
Efficiency vs Output Current
(Figure 13)
100
V_IN = 7V
90
V_IN = 10V
80
V_IN = 15V
V_IN = 20V
70
60
50
0.001
V_OUT = 5V
0.01
0.1
1
10
OUTPUT CURRENT (A)
3727 G02
4
Efficiency vs Input Voltage
(Figure 13)
100
V_OUT = 5V
I_OUT = 3A
90
80
70
60
50
5
15
25
INPUT VOLTAGE (V)
35
3727 G03
3727fc