LTC1877 Linear Technology, LTC1877 Datasheet - Page 3

• Manufacturer Part Number: LTC1877
• Description: High Efficiency Monolithic Synchronous Step-Down Regulator
• Manufacturer: Linear Technology

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.
ELECTRICAL CHARACTERISTICS
The
V
SYMBOL
I
I
V
I
V
I
TYPICAL PERFORMANCE CHARACTERISTICS
PK
LSW
SYNC/MODE
RUN
SYNC/MODE
RUN
IN
100
= 5V unless otherwise specified.
95
90
85
80
75
70
65
60
55
50
denotes specifications which apply over the full operating temperature range, otherwise specifications are T A = 25 C.
0
Efficiency vs Input Voltage
V
L = 10 H
Burst Mode OPERATION
OUT
PARAMETER
Peak Inductor Current
SW Leakage
SYNC/MODE Threshold
SYNC/MODE Leakage Current
RUN Threshold
RUN Input Current
2
= 2.5V
I
LOAD
INPUT VOLTAGE (V)
I
LOAD
4
= 100mA I
= 300mA
6
I
LOAD
LOAD
8
I
LOAD
= 0.1mA
W
= 10mA
10
= 1mA
1877 • G01
U
12
CONDITIONS
V
V
FB
RUN
100
90
80
70
60
50
40
30
20
10
= 0.7V, Duty Cycle < 35%
0
0.1
= 0V, V
Efficiency vs Output Current
V
IN
= 3.6V
V
SW
IN
1.0
V
= 7.2V
OUTPUT CURRENT (mA)
= 0V or 8.5V, V
IN
= 3.6V
PULSE SKIPPING MODE
Burst Mode OPERATION
10
Note 3: T
dissipation P
Note 4: The LTC1877 is tested in a feedback loop which servos V
balance point for the error amplifier (V
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
V
IN
LTC1877EMS8: T
= 7.2V
IN
= 8.5V
100
V
L = 10 H
J
OUT
is calculated from the ambient temperature T
D
= 2.5V
1877 • G02
according to the following formulas:
1000
J
= T
A
+ (P
95
90
85
80
75
70
65
60
55
0.1
D
Efficiency vs Output Current
)(150 C/W)
MIN
0.8
0.2
0.2
ITH
1.0
OUTPUT CURRENT (mA)
= 1.2V).
TYP
1.0
1.0
0.7
0.01
0.01
0.01
L = 15 H
V
V
Burst Mode OPERATION
10
IN
OUT
= 10V
LTC1877
= 3.3V
A
MAX
1.25
L = 10 H
1.5
1.5
and power
1
1
1
100
FB
1877 • G03
to the
UNITS
3
1000
A
A
V
A
V
A