EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LTC3872ETS8-1#PBF
LTC3872ITS8-1#PBF
LTC3872HTS8-1#PBF
LTC3872EDDB-1#PBF
LTC3872IDDB-1#PBF
LTC3872HDDB-1#PBF
TAPE AND REEL
LTC3872ETS8-1#TRPBF
LTC3872ITS8-1#TRPBF
LTC3872HTS8-1#TRPBF
LTC3872EDDB-1#TRPBF
LTC3872IDDB-1#TRPBF
LTC3872HDDB-1#TRPBF
PART MARKING*
LTCFN
LTCFN
LTCFN
LCFK
LCFK
LCFK
PACKAGE DESCRIPTION
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead (3mm
×
2mm) Plastic DFN
8-Lead (3mm
×
2mm) Plastic DFN
8-Lead (3mm
×
2mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 125°C
–40°C to 150°C
–40°C to 85°C
–40°C to 125°C
–40°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
38721f
2
For more information
www.linear.com/LTC3872-1
LTC3872-1
elecTrical characTerisTics
PARAMETER
Input Voltage Range
Input DC Supply Current
Normal Operation
Shutdown
UVLO
Undervoltage Lockout Threshold
Shutdown Threshold (at RUN/SS)
Regulated Feedback Voltage
Feedback Voltage Line Regulation
Feedback Voltage Load Regulation
V
FB
Input Current
RUN/SS Pull Up Current
Oscillator Frequency
Normal Operation
Gate Drive Rise Time
Gate Drive Fall Time
Peak Current Sense Voltage
Typicals at V
IN
= 4.2V (Note 4)
2.75V ≤ V
IN
≤ 9.8V
V
RUN/SS
= 0V
V
IN
< UVLO Threshold
V
IN
Rising
V
IN
Falling
V
RUN/SS
Falling
V
RUN/SS
Rising
(Note 5) LTC3872-1E
LTC3872-1I and LTC3872-1H
2.75V < V
IN
< 9V (Note 5)
V
ITH
= 1.6V (Note 5)
V
ITH
= 1V (Note 5)
(Note 5)
V
RUN/SS
= 0
V
FB
= 1V
C
LOAD
= 3000pF
C
LOAD
= 3000pF
IPRG = GND (Note 6)
LTC3872-1E
LTC3872-1I
LTC3872-1H
LTC3872-1E
LTC3872-1I
LTC3872-1H
LTC3872-1E
LTC3872-1I
LTC3872-1H
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 4.2V unless otherwise noted.
CONDITIONS
l
MIN
2.75
TYP
MAX
9.8
UNITS
V
µA
µA
µA
V
V
V
V
V
V
mV/V
%
%
250
8
20
2.3
2.05
0.6
0.65
1.182
1.178
2.45
2.3
0.85
0.95
1.2
1.2
0.14
0.05
–0.05
25
0.35
500
0.7
550
40
40
90
85
80
160
150
145
260
250
240
105
105
105
180
180
180
285
285
285
1
400
20
35
2.75
2.55
1.05
1.15
1.218
1.218
50
1.25
650
nA
µA
kHz
ns
ns
120
120
120
200
200
200
310
310
310
mV
mV
mV
mV
mV
mV
mV
mV
mV
ms
IPRG = Float
IPRG = V
IN
Default Internal Soft-Start Time
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 LTC3872-1 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3872-1E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3872-1I is guaranteed
over the –40°C to 125°C operating junction temperature range. The
LTC3872-1H is guaranteed over the full –40°C to 150°C operating junction
temperature range. The maximum ambient temperature consistent with
these specifications is determined by specific operating conditions in
conjunction with board layout, the rated package thermal impedance and
other environmental factors.
Note 3:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC3872-1TS8: T
J
= T
A
+ (P
D
• 195°C/W)
LTC3872-1DDB: T
J
= T
A
+ (P
D
• 76°C/W)
Note 4:
The dynamic input supply current is higher due to power MOSFET
gate charging (Q
G
• f
OSC
). See Applications Information.
Note 5:
The LTC3872-1 is tested in a feedback loop which servos V
FB
to
the reference voltage with the I
TH
pin forced to the midpoint of its voltage
range (0.7V ≤ V
ITH
≤ 1.9V, midpoint = 1.3V).
Note 6:
Rise and fall times are measured at 10% and 90% levels.
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