LTC1877 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC1877' PDF : 16 Pages View PDF
LTC1877
ELECTRICAL CHARACTERISTICS
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C.
VIN = 5V unless otherwise specified.
SYMBOL
IPK
ILSW
VSYNC/MODE
ISYNC/MODE
VRUN
IRUN
PARAMETER
Peak Inductor Current
SW Leakage
SYNC/MODE Threshold
SYNC/MODE Leakage Current
RUN Threshold
RUN Input Current
CONDITIONS
VFB = 0.7V, Duty Cycle < 35%
VRUN = 0V, VSW = 0V or 8.5V, VIN = 8.5V
MIN TYP MAX
UNITS
0.8
1.0
1.25
A
±0.01 ±1
µA
q
0.2
1.0
1.5
V
±0.01 ±1
µA
q
0.2
0.7
1.5
V
±0.01 ±1
µA
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTC1877 is guaranteed to meet specified performance 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.
Note 3: TJ is calculated from the ambient temperature TA and power
dissipation PD according to the following formulas:
LTC1877EMS8: TJ = TA + (PD)(150°C/W)
Note 4: The LTC1877 is tested in a feedback loop which servos VFB to the
balance point for the error amplifier (VITH = 1.2V).
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Input Voltage
100
95
ILOAD = 100mA ILOAD = 10mA
90
85
ILOAD = 300mA
80
ILOAD = 1mA
75
70
ILOAD = 0.1mA
65
60 VOUT = 2.5V
55 L = 10µH
Burst Mode OPERATION
50
0
2
4
6
8
10 12
INPUT VOLTAGE (V)
1877 • G01
Efficiency vs Output Current
100
VIN = 3.6V
90
80
VIN = 7.2V
70
VIN = 7.2V
60 VIN = 3.6V
50
40
30
20
10
0
0.1
PULSE SKIPPING MODE
Burst Mode OPERATION
VOUT = 2.5V
L = 10µH
1.0
10
100
OUTPUT CURRENT (mA)
1000
1877 • G02
Efficiency vs Output Current
95
90
L = 15µH
85
L = 10µH
80
75
70
65
60
55
0.1
VIN = 10V
VOUT = 3.3V
Burst Mode OPERATION
1.0
10
100
OUTPUT CURRENT (mA)
1000
1877 • G03
3
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