EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
MSE PACKAGE
10-LEAD PLASTIC MSOP
θ
JA
= 45°C,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
MSE PACKAGE
10-LEAD PLASTIC MSOP
θ
JA
= 45°C,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LT3991EDD#PBF
LT3991IDD#PBF
LT3991EMSE#PBF
LT3991IMSE#PBF
LT3991EMSE-3.3#PBF
LT3991IMSE-3.3#PBF
LT3991EMSE-5#PBF
LT3991IMSE-5#PBF
TAPE AND REEL
LT3991EDD#TRPBF
LT3991IDD#TRPBF
LT3991EMSE#TRPBF
LT3991IMSE#TRPBF
LT3991EMSE-3.3#TRPBF
LT3991IMSE-3.3#TRPBF
LT3991EMSE-5#TRPBF
LT3991IMSE-5#TRPBF
PART MARKING*
LFJR
LFJR
LTFJS
LTFJS
LTFRS
LTFRS
LTFRV
LTFRV
PACKAGE DESCRIPTION
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°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/
2
3991fa
LT3991/LT3991-3.3/LT3991-5
elecTrical characTerisTics
PARAMETER
Minimum Input Voltage
Quiescent Current from V
IN
LT3991 FB Pin Current
Internal Feedback Resistor Divider
Feedback Voltage
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
EN
= 12V, V
BD
= 3.3V unless otherwise noted. (Note 2)
CONDITIONS
(Note 4)
V
EN
Low
V
EN
High, V
SYNC
Low
V
EN
High, V
SYNC
Low
V
FB
= 1.19V
l
MIN
TYP
4
0.7
1.7
MAX
4.3
1.2
2.7
4.5
12
1.205
1.215
3.35
3.376
5.07
5.11
0.01
2.4
1.2
240
200
2.9
1
1
1.8
33
1.07
20
140
12.5
1
1.0
1.6
UNITS
V
μA
μA
μA
nA
MΩ
V
V
V
V
V
V
%/V
MHz
MHz
kHz
ns
ns
A
mV
μA
mV
μA
V
mA
V
mV
nA
mV
mV
%
%
µA
μA
V
nA
μA
l
l
0.1
10
1.175
1.165
3.25
3.224
4.93
4.89
1.6
0.8
160
1.19
1.19
3.3
3.3
5
5
0.0002
2
1
200
110
150
1.7
2.3
440
0.02
800
0.02
LT3991-3.3 Output Voltage
l
LT3991-5 Output Voltage
l
FB Voltage Line Regulation
Switching Frequency
4.3V < V
IN
< 40V (Note 4)
R
T
= 11k
R
T
= 35.7k
R
T
= 255k
Minimum Switch On Time
Minimum Switch Off Time
Switch Current Limit
Switch V
CESAT
Switch Leakage Current
Boost Schottky Forward Voltage
Boost Schottky Reverse Leakage
Minimum Boost Voltage (Note 3)
BOOST Pin Current
EN Voltage Threshold
EN Voltage Hysteresis
EN Pin Current
LT3991 PG Threshold Offset from V
FB
LT3991 PG Hysteresis
LT3991-X PG Threshold Offset from V
OUT
LT3991X PG Hysteresis
PG Leakage
PG Sink Current
SYNC Threshold
SYNC Pin Current
SS Source Current
V
SS
= 1V
0.6
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 LT3991E is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization, and correlation with statistical process controls.
V
PG
= 3V
V
PG
= 0.4V
l
I
SW
= 1A
I
SH
= 100mA
V
REVERSE
= 12V
V
IN
= 5V
I
SW
= 1A, V
BOOST
= 15V
EN Rising
l
l
1.4
25
0.95
1.01
30
0.2
V
FB
Rising
V
OUT
Rising
60
5.5
100
20
9
1.3
0.02
300
0.6
570
0.8
0.1
1
The LT3991I is guaranteed over the full –40°C to 125°C operating junction
temperature range. High junction temperatures degrade operating
lifetimes. Operating lifetime is derated at junction temperatures greater
than 125°C.
Note 3:
This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the switch.
Note 4:
Minimum input voltage depends on application circuit.
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