LTC1142_15 Datasheet, PDF (4/20 Pages) Linear Technology – Dual High Efficiency Synchronous Step-Down Switching Regulators

LTC1142/LTC1142L/LTC1142HV
ELECTRICAL CHARACTERISTICS _{–40°C ≤ TA ≤ 85°C (Note 5), V10 = V24 = 10V, unless otherwise noted.}
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
V_SHDN
t_OFF
Shutdown Pin Threshold
Off-Time (Note 4)
LTC1142, LTC1142HV
V₁₄ = V_OUT + 100mV (Forced)
V₁₄ = V_OUT – 100mV (Forced)
C_T = 390pF, I_LOAD = 700mA
25
mV
125 150 175
mV
0.55 0.8 2
V
3.8 5
6
µs
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: T_J is calculated from the ambient temperature T_A and power
dissipation P_D according to the following formula:
LTC1142CG: T_J = T_A + (P_D × 95°C/ W)
Note 3: This current is for one regulator block. Total supply current is the
sum of Pins 10 and 24 currents. Dynamic supply current is higher due to
the gate charge being delivered at the switching frequency. See the
Applications Information section.
Note 4: In applications where R_SENSE is placed at ground potential, the off-
time increases approximately 40%.
Note 5: The LTC1142/LTC1142L/LTC1142HV are guaranteed to meet
specified performance from 0°C to 70°C and are designed, characterized
and expected to meet these extended temperature limits, but are not tested
at – 40°C and 85°C. Guaranteed I-grade parts are available, consult the
factory.
Note 6: The LTC1142L-ADJ allows operation down to V_IN = 3.5V.
TYPICAL PERFOR A CE CHARACTERISTICS
5V Output Efficiency
100
V_IN = 6V
95
V_IN = 10V
90
3.3V Output Efficiency
100
V_IN = 5V
95
V_IN = 10V
90
85
0.01
0.1
LOAD CURRENT (A)
12
1142 G01
3.3V Efficiency vs Input Voltage
100
98
FIGURE 1 CIRCUIT
V_OUT = 3.3V
96
94
I_LOAD = 1A
92
90
I_LOAD = 100mA
88
86
84
82
80
0
4
8
12
16
20
INPUT VOLTAGE (V)
1142 G04
4
85
0.01
0.1
LOAD CURRENT (A)
12
1142 G02
Line Regulation
40
FIGURE 1 CIRCUIT
30 _{ILOAD = 1A}
20
10
0
– 10
– 20
– 30
– 40
0
4
8
12
16
20
INPUT VOLTAGE (V)
1142 G05
5V Efficiency vs Input Voltage
100
98
96
94
92
90
88
86
84
82
80
0
FIGURE 1 CIRCUIT
V_OUT = 5V
I_LOAD = 1A
I_LOAD = 100mA
4
8
12
16
20
INPUT VOLTAGE (V)
1142 G03
Load Regulation
20
FIGURE 1 CIRCUIT
R_SENSE = 0.05Ω
0
–20
V_IN = 6V
V_IN = 12V
– 40
– 60
– 80
– 100
0
V_IN = 6V
V_OUT = 5V
V_OUT = 3.3V
V_IN = 12V
0.5 1.0 1.5 2.0 2.5
LOAD CURRENT (A)
1142 G06