Datasheet
4
LTC1148
LTC1148-3.3/LTC1148-5
114835fd
E
LECTR
IC
AL C CHARA TERIST
ICS
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 formulas:
LTC1148CN, LTC1148CN-3.3, LTC1148CN-5: T
J
= T
A
+ (P
D
× 70°C/W)
LTC1148CS, LTC1148CS-3.3, LTC1148CS-5: T
J
= T
A
+ (P
D
× 110°C/W)
Note 3: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 4: The LTC1148 and LTC1148HV versions are tested with external
feedback resistors resulting in a nominal output voltage of 5V. The
LTC1148L version is tested with external feedback resistors resulting in a
nominal output voltage of 2.5V.
Note 5: In applications where R
SENSE
is placed at ground potential, the off
time increases approximately 40%.
Note 6: The LTC1148, LTC1148HV and LTC1148L series are not tested
and not quality assurance sampled at –40°C and 85°C. These
specifications are guaranteed by design and/or correlation. The
LTC1148HVI-5 is guaranteed over the full –40°C to 85°C operating
temperature range.
Note 7: The LTC1148L and LTC1148L-3.3 allow operation to V
IN
= 3.5V.
CCHARA TERIST
ICS
UW
AT
Y
P
I
CA
LPER
F
O
R
C
E
Line RegulationEfficiency vs Input Voltage
LOAD CURRENT (A)
0
–100
∆V
OUT
(mV)
–80
–60
–40
–20
0
20
0.5 1 1.5 2
LTC1148 • TPC03
2.5
FIGURE 1 CIRCUIT
R
SENSE
= 0.05Ω
V
IN
= 6V
V
IN
= 12V
INPUT VOLTAGE (V)
0
80
EFFICIENCY (%)
82
86
88
90
100
94
4
8
LTC1148 • TPC01
84
96
98
92
12
16
20
I
LOAD
= 100mA
FIGURE 1 CIRCUIT
I
LOAD
= 1A
DC Supply Current
Supply Current in Shutdown
Load Regulation
Operating Frequency
vs (V
IN
– V
OUT
)
(V
IN
– V
OUT
) VOLTAGE (V)
0
NORMALIZED FREQUENCY
0.6
1.0
8
LTC1148 • TPC06
0.4
0
2
4
6
0.2
1.2
0.8
10 12
1.4
1.6
V
OUT
= 5V
0°C
70°C
25°C
INPUT VOLTAGE
0
0
SUPPLY CURRENT (mA)
0.3
0.9
1.2
1.5
4
LTC1148 • TPC04
0.6
26
1.8
2.1
8 10 12 14 16 18
SLEEP MODE
ACTIVE MODE
NOT INCLUDING
GATE CHARGE CURRENT
20
INPUT VOLTAGE (V)
0
0
SUPPLY CURRENT (µA)
2
6
8
10
20
14
4
8
10 18
LTC1148 • TPC05
4
16
18
12
26
12
14
16
V
SHUTDOWN
= 2V
20
INPUT VOLTAGE (V)
0
∆V
OUT
(mV)
0
10
20
16
LTC1148 • TPC02
–10
–20
–40
4
812
–30
40
30
FIGURE 1 CIRCUIT
I
LOAD
= 1A
20