LTC3728 Datasheet, PDF (4/32 Pages) Linear Technology – Dual, 550kHz, 2-Phase Synchronous Step-Down Switching Regulator

LTC3728
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
PARAMETER
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
No Load
I_3.3 = 0 to 10mA
6V < V_IN < 30V
I_PGOOD = 2mA
V_PGOOD = 5V
V_OSENSE with Respect to Set Output Voltage
V_OSENSE Ramping Negative
V_OSENSE Ramping Positive
MIN TYP MAX UNITS
● 3.25 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
reliabilty and lifetime.
Note 2: T_J is calculated from the ambient temperature T_A and power
dissipation P_D according to the following formulas:
LTC3728: T_J = T_A + (P_D • 95 °C/W)
Note 3: The LTC3728 is tested in a feedback loop that servos V_{ITH1, 2} to a
specified voltage and measures the resultant V_{OSENSE1, 2.}
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 5: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 6: 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 7: The LTC3728E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the – 40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
TYPICAL PERFOR A CE CHARACTERISTICS
Efficiency vs Output Current
and Mode (Figure 13)
100
Burst Mode
90 _OPERATION
80
70
FORCED
60
CONTINUOUS
50
MODE (PWM)
40
30
20
10
0
0.001
CONSTANT
FREQUENCY
(BURST DISABLE)
V_IN = 15V
V_OUT = 5V
f = 250kHz
0.01
0.1
1
10
OUTPUT CURRENT (A)
3728 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
f = 250kHz
0.01
0.1
1
10
OUTPUT CURRENT (A)
3728 G02
Efficiency vs Input Voltage
(Figure 13)
100
90
80
70
60
V_OUT = 5V
I_OUT = 3A
f = 250kHz
50
5
15
25
35
INPUT VOLTAGE (V)
3728 G03
3728fb
4