LTC3834 Datasheet, PDF (4/28 Pages) Linear Technology – 30μA IQ Synchronous Step-Down Controller

LTC3834
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 = 12V, V_RUN = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
PGOOD Output
V_PGL
I_PGOOD
V_PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
I_PGOOD = 2mA
V_PGOOD = 5V
V_FB with Respect to Set Regulated Voltage
V_FB Ramping Negative
V_FB Ramping Positive
0.1 0.3
V
±1
μA
–12 –10 –8
%
8
10 12
%
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 LTC3834E 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 LTC3834I 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:
LTC3834FE: T_J = T_A + (P_D • 35°C/W)
LTC3834UFD: T_J = T_A + (P_D • 37°C/W)
Note 4: The LTC3834 is tested in a feedback loop that servos V_ITH to a
specified voltage and measures the resultant V_FB.
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 PERFORMANCE CHARACTERISTICS T_A = 25°C, unless otherwise noted.
Efficiency and Power Loss
vs Output Current
100
Burst Mode OPERATION
90
FORCED CONTINUOUS MODE
PULSE SKIPPING MODE
80 _{VIN = 12V}
70 ^VOUT ^{= 3.3V}
10000
1000
60
100
50
40
10
30
20
1
10
0
0.000001
FIGURE 11 CIRCUIT
0.1
0.0001
0.01
1
OUTPUT CURRENT (A)
3834 G01
Efficiency vs Load Current
100
V_IN = 12V
V_IN = 5V
90 _{VOUT = 3.3V}
80
70
60
50
40
0.000001
FIGURE 11 CIRCUIT
0.0001
0.01
OUTPUT CURRENT (A)
1
3834 G02
Efficiency vs Input Voltage
98
V_OUT = 3.3V
96 FIGURE 11 CIRCUIT
94
92
90
88
86
84
82
80
0 5 10 15 20 25 30 35 40
INPUT VOLTAGE (V)
3834 G03
3834fb
4