EXPOSED PAD (PIN 9) IS GND MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LTC3872ETS8#PBF
LTC3872ITS8#PBF
LTC3872HTS8#PBF
LTC3872EDDB#PBF
LTC3872IDDB#PBF
LTC3872HDDB#PBF
TAPE AND REEL
LTC3872ETS8#TRPBF
LTC3872ITS8#TRPBF
LTC3872HTS8#TRPBF
LTC3872EDDB#TRPBF
LTC3872IDDB#TRPBF
LTC3872HDDB#TRPBF
PART MARKING*
LCGB
LCGB
LCGB
LCHT
LCHT
LCHT
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/
3872fc
2
For more information
www.linear.com/LTC3872
LTC3872
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) LTC3872E
LTC3872I and LTC3872H
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)
LTC3872E
LTC3872I
LTC3872H
LTC3872E
LTC3872I
LTC3872H
LTC3872E
LTC3872I
LTC3872H
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
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
80
70
65
145
135
130
240
225
215
100
100
100
170
170
170
270
270
270
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
195
195
195
290
290
290
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 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3872E 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 LTC3872I is guaranteed
over the –40°C to 125°C operating junction temperature range. The
LTC3872H 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:
LTC3872TS8: T
J
= T
A
+ (P
D
• 195°C/W)
LTC3872DDB: 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 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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