FEATURES
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LT8362
Low I
Q
Boost/SEPIC/
Inverting Converter
with 2A, 60V Switch
DESCRIPTION
The
LT
®
8362
is a current mode DC/DC converter with a
60V, 2A switch operating from a 2.8V to 60V input. With
a unique single feedback pin architecture it is capable
of boost, SEPIC or inverting configurations. Burst Mode
operation consumes as low as 9µA quiescent current to
maintain high efficiency at very low output currents, while
keeping typical output ripple below 15mV.
An external compensation pin allows optimization of loop
bandwidth over a wide range of input and output volt-
ages and programmable switching frequencies between
300kHz and 2MHz. A SYNC/MODE pin allows synchroni-
zation to an external clock. It can also be used to select
between burst or pulse-skipping modes of operation with
or without Spread Spectrum Frequency Modulation for
low EMI. For increased efficiency, a BIAS pin can accept
a second input to supply the INTV
CC
regulator. Additional
features include frequency foldback and programmable
soft-start to control inductor current during start-up.
The LT8362 is available in a thermally enhanced 10-lead
3mm
×
3mm DFN package or a thermally enhanced
16-lead MSOP package with four pins removed.
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Wide Input Voltage Range: 2.8V to 60V
Ultralow Quiescent Current and Low Ripple
Burst Mode
®
Operation: I
Q
= 9µA
2A, 60V Power Switch
Positive or Negative Output Voltage Programming
with a Single Feedback Pin
Programmable Frequency (300kHz to 2MHz)
Synchronizable to an External Clock
Spread Spectrum Frequency Modulation for Low EMI
BIAS Pin for Higher Efficiency
Programmable Undervoltage Lockout (UVLO)
Thermally Enhanced 10-Lead 3mm
×
3mm DFN and
16-Lead MSOP packages
APPLICATIONS
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Industrial and Automotive
Telecom
Medical Diagnostic Equipment
Portable Electronics
All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION
2MHz, 48V Output Boost Converter
V
IN
8V TO 38V
6.8 H
4.7µF
V
IN
EN/UVLO
LT8362
SW
FBX
BIAS
INTV
CC
GND V
C
57.6k
10nF
150pF
8362 TA01a
Efficiency and Power Loss
V
OUT
48V
200mA AT V
IN
= 8V
320mA AT V
IN
= 12V
700mA AT V
IN
= 24V
EFFICIENCY (%)
4.7µF
100
90
80
70
60
50
40
30
20
10
0
0
0.1
0.2
POWER LOSS
V
IN
= 12V
V
IN
= 24V
0.3 0.4 0.5 0.6
LOAD CURRENT (A)
0.7
EFFICIENCY
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0.8
POWER LOSS (W)
1M
4.7pF
SYNC/MODE
RT
20k
SS
1µF
34.8k
8362 TA01b
8362fa
For more information
www.linear.com/LT8362
1
LT8362
ABSOLUTE MAXIMUM RATINGS
(Note 1)
SW ............................................................................ 60V FBX ........................................................................... ±4V
V
IN
, EN/UVLO............................................................ 60V Operating Junction Temperature (Note 3)
BIAS .......................................................................... 40V
LT8362E, LT8362I...............................–40°C to 125°C
EN/UVLO Pin Above V
IN
Pin, SYNC............................. 6V
LT8362H .............................................–40°C to 150°C
INTV
CC
...............................................................(Note 2) Storage Temperature Range ...................–65°C to 150°C
V
C
............................................................................... 4V
PIN CONFIGURATION
TOP VIEW
EN/UVLO 1
V
IN
3
INTV
CC
NC
BIAS
V
C
5
6
7
8
17
PGND,
GND
16 SW1
14 SW2
12
11
10
9
SYNC/MODE
SS
RT
FBX
EN/UVLO
V
IN
INTV
CC
BIAS
V
C
1
2
3
4
5
11
PGND,
GND
TOP VIEW
10 SW
9 SYNC/MODE
8 SS
7 RT
6 FBX
MSE PACKAGE
VARIATION: MSE16 (12)
16-LEAD PLASTIC MSOP
θ
JA
= 45°C/W,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 17) IS PGND AND GND, MUST BE SOLDERED TO PCB
DD PACKAGE
10-LEAD (3mm
×
3mm) PLASTIC DFN
θ
JA
= 43°C/W
EXPOSED PAD (PIN 11) IS PGND AND GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT8362EMSE#PBF
LT8362IMSE#PBF
LT8362HMSE#PBF
LT8362EDD#PBF
LT8362IDD#PBF
LT8362HDD#PBF
TAPE AND REEL
LT8362EMSE#TRPBF
LT8362IMSE#TRPBF
LT8362HMSE#TRPBF
LT8362EDD#TRPBF
LT8362IDD#TRPBF
LT8362HDD#TRPBF
http://www.linear.com/product/LT8362#orderinfo
PART MARKING*
8362
8362
8362
LGWZ
LGWZ
LGWZ
PACKAGE DESCRIPTION
16-Lead Plastic MSOP with 4 Pins Removed
16-Lead Plastic MSOP with 4 Pins Removed
16-Lead Plastic MSOP with 4 Pins Removed
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–40°C to 125°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 nonstandard 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/
8362fa
2
For more information
www.linear.com/LT8362
LT8362
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, EN/UVLO = 12V unless otherwise noted.
PARAMETER
V
IN
Operating Voltage Range
V
IN
Quiescent Current at Shutdown
V
EN/UVLO
= 0.2V
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
l
TYP
1
1
2
2
9
9
1200
1200
22
22
4.4
4
BIAS – 2V
V
IN
MAX
60
2
15
5
25
15
30
1600
1850
40
65
4.65
4.25
UNITS
V
μA
μA
μA
μA
μA
μA
µA
µA
µA
µA
V
V
V
V
2.8
V
EN/UVLO
= 1.5V
l
V
IN
Quiescent Current
Sleep Mode (Not Switching)
Active Mode (Not Switching)
SYNC = 0V
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SYNC = 0V or INTV
CC
, BIAS = 0V
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SYNC = 0V or INTV
CC
, BIAS = 5V
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BIAS Threshold
V
IN
Falling Threshold to Supply INTV
CC
BIAS Falling Threshold to Supply INTV
CC
FBX Regulation
FBX Regulation Voltage
FBX Line Regulation
FBX Pin Current
Oscillator
Switching Frequency (f
OSC
)
SSFM Maximum Frequency Deviation
Minimum On-Time
Minimum Off-Time
SYNC/Mode, Mode Thresholds (Note 5)
SYNC/Mode, Clock Thresholds (Note 5)
f
SYNC
/f
OSC
Allowed Ratio
SYNC Pin Current
Switch
Maximum Switch Current Limit Threshold
Switch Overcurrent Threshold
Switch R
DS(ON)
Switch Leakage Current
Rising, BIAS Can Supply INTV
CC
Falling, BIAS Cannot Supply INTV
CC
BIAS = 12V
V
IN
= 12V
FBX > 0V
FBX < 0V
FBX > 0V, 2.8V < V
IN
< 60V
FBX < 0V, 2.8V < V
IN
< 60V
FBX = 1.6V, –0.8V
R
T
= 165k
R
T
= 45.3k
R
T
= 20k
(∆f/f
OSC
) • 100, R
T
= 20k
Burst Mode, V
IN
= 24V (Note 6)
Pulse-Skip Mode, V
IN
= 24V (Note 6)
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1.568
–0.820
1.6
–0.80
0.005
0.005
1.632
–0.780
0.015
0.015
10
V
V
%/V
%/V
nA
kHz
MHz
MHz
%
ns
ns
ns
V
V
V
V
kHz/kHz
µA
µA
A
A
mΩ
–10
273
0.92
1.85
14
300
1
2
20
70
60
50
0.14
0.4
0.95
1.3
0.2
1.3
0.8
1
10
10
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327
1.08
2.15
25
90
85
75
1.7
1.7
1.25
25
25
3.1
High (Rising)
Low (Falling)
Rising
Falling
R
T
= 20k
SYNC = 2V
SYNC = 0V, Current Out of Pin
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2
2.5
3.75
165
0.1
Discharges SS Pin
I
SW
= 0.5A
V
SW
= 60V
1
µA
8362fa
For more information
www.linear.com/LT8362
3
LT8362
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, EN/UVLO = 12V unless otherwise noted.
PARAMETER
EN/UVLO Logic
EN/UVLO Pin Threshold (Rising)
EN/UVLO Pin Threshold (Falling)
EN/UVLO Pin Current
Soft-Start
Soft-Start Charge Current
Soft-Start Pull-Down Resistance
Error Amplifier
Error Amplifier Transconductance
Error Amplifier Voltage Gain
Error Amplifier Max Source Current
Error Amplifier Max Sink Current
FBX = 1.6V
FBX = –0.8V
FBX = 1.6V
FBX = –0.8V
V
C
= 1.1V, Current Out of Pin
V
C
= 1.1V
75
60
185
145
7
7
µA/V
µA/V
V/V
V/V
µA
µA
SS = 0.5V
Fault Condition, SS = 0.1V
2
220
µA
Ω
Start Switching
Stop Switching
V
EN/UVLO
= 1.6V
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ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
1.576
1.555
–50
TYP
1.68
1.6
MAX
1.90
1.645
50
UNITS
V
V
nA
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:
INTV
CC
cannot be externally driven. No additional components or
loading is allowed on this pin.
Note 3:
The LT8362E 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. The
LT8362I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT8362H is guaranteed over the full –40°C to
150°C operating junction temperature range.
Note 4:
The IC includes overtemperature protection that is intended to
protect the device during overload conditions. Junction temperature will
exceed 150°C when overtemperature protection is active. Continuous
operation above the specified maximum operating junction temperature
will reduce lifetime.
Note 5:
For SYNC/MODE inputs required to select modes of operation see
the Pin Functions and Applications Information sections.
Note 6:
The IC is tested in a Boost converter configuration with the output
voltage programmed for 24V.
8362fa
4
For more information
www.linear.com/LT8362
LT8362
TYPICAL PERFORMANCE CHARACTERISTICS
FBX Positive Regulation Voltage
vs Temperature
1.632
1.624
1.616
FBX VOLTAGE (V)
FBX VOLTAGE (V)
1.608
1.600
1.592
1.584
1.576
1.568
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8362 G01
FBX Negative Regulation Voltage
vs Temperature
–0.780
–0.785
–0.790
–0.795
–0.800
–0.805
–0.810
–0.815
–0.820
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8362 G02
EN/UVLO Pin Thresholds
vs Temperature
1.74
1.72
EN/UVLO PIN VOLTAGE (V)
1.70
1.68
1.66
1.64
1.62
1.60
1.58
1.56
1.54
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8362 G03
V
IN
= 12V
V
IN
= 12V
EN/UVLO RISING (TURN–ON)
EN/UVLO FALLING (TURN–OFF)
Switching Frequency
vs Temperature
2.10
2.08
SWITCHING FREQUENCY (MHz)
2.06
2.04
2.02
2.00
1.98
1.96
1.94
1.92
1.90
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8362 G04
2.08
SWITCHING FREQUENCY (MHz)
2.06
2.04
2.02
2.00
1.98
1.96
1.94
1.92
1.90
0
5 10 15 20 25 30 35 40 45 50 55 60
V
IN
(V)
8362 G05
NORMALIZED SWITCHING FREQUENCY (%)
V
IN
= 12V
2.10
Switching Frequency vs V
IN
Normalized Switching Frequency
vs FBX Voltage
125
V
IN
= 12V
100
75
50
25
0
–0.8
–0.4
0.0
0.4
0.8
VOLTAGE (V)
1.2
1.6
8362 G06
Switch Current Limit
vs Duty Cycle
3.0
2.9
SWITCH CURRENT LIMIT (A)
2.8
MINIMUM ON TIME (ns)
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2.0
0
10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
8362 G07
Switch Minimum On-Time
vs Temperature
100
90
80
70
60
50
40
30
20
10
0
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8362 G08
Switch Minimum Off-Time
vs Temperature
100
90
MINIMUM OFF TIME (ns)
80
70
60
50
40
30
20
10
0
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8362 G09
V
IN
= 12V
V
IN
= 12V
V
IN
= 12V
8362fa
For more information
www.linear.com/LT8362
5
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