internal 2A, 42V switch. The LT3580 can be configured
as either a boost, SEPIC or inverting converter. Capable
of generating 12V at 550mA or –12V at 350mA from a
5V input, the LT3580 is ideal for many local power supply
designs.
The LT3580 has an adjustable oscillator, set by a resistor
from the RT pin to ground. Additionally, the LT3580 can
be synchronized to an external clock. The free running or
synchronized switching frequency range of the part can
be set between 200kHz and 2.5MHz.
The LT3580 also features innovative
SHDN
pin circuitry
that allows for slowly varying input signals and an adjust-
able undervoltage lockout function.
Additional features such as frequency foldback and
soft-start are integrated. The LT3580 is available in tiny
3mm
×
3mm 8-lead DFN and 8-lead MSOP packages.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
2A Internal Power Switch
Adjustable Switching Frequency
Single Feedback Resistor Sets V
OUT
Synchronizable to External Clock
High Gain
SHDN
Pin Accepts Slowly Varying
Input Signals
Wide Input Voltage Range: 2.5V to 32V
Low V
CESAT
Switch: 300mV at 1.5A (Typical)
Integrated Soft-Start Function
Easily Configurable as a Boost or Inverting Converter
User Configurable Undervoltage Lockout (UVLO)
Tiny 8-Lead 3mm
×
3mm DFN and 8-Lead MSOP
Packages
APPLICATIONS
n
n
n
n
n
VFD Bias Supplies
TFT-LCD Bias Supplies
GPS Receivers
DSL Modems
Local Power Supply
TYPICAL APPLICATION
1.2MHz, 5V to 12V Boost Converter Achieves Over 88% Efficiency
95
V
IN
5V
V
IN
SHDN
LT3580
RT
SYNC
2.2μF
75k
SS
0.1μF
FB
VC
10k
1nF
3580 TA01
Efficiency and Power Loss
1200
1000
85
POWER LOSS (mW)
EFFICIENCY (%)
80
75
600
70
65
60
200
55
50
0
100
200
300
400
LOAD CURRENT (mA)
500
600
0
400
800
90
4.2μH
V
OUT
12V
550mA
SW
GND
130k
10μF
3580 TA01b
3580fg
1
LT3580
ABSOLUTE MAXIMUM RATINGS
(Note 1)
V
IN
Voltage ................................................. –0.3V to 32V
SW Voltage ................................................ –0.4V to 42V
RT Voltage ................................................... –0.3V to 5V
SS and FB Voltage .................................... –0.3V to 2.5V
VC Voltage ................................................... –0.3V to 2V
SHDN
Voltage ............................................ –0.3V to 32V
SYNC Voltage............................................ –0.3V to 5.5V
Operating Junction Temperature Range
LT3580E (Notes 2, 5)......................... –40°C to 125°C
LT3580I (Notes 2, 5).......................... –40°C to 125°C
LT3580H (Notes 2, 5) ........................–40°C to 150°C
LT3580MP (Notes 2, 5) ..................... –55°C to 125°C
Storage Temperature Range ..................–65°C to 150°C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
FB 1
VC 2
V
IN
3
SW 4
9
GND
8
7
6
5
SYNC
SS
RT
SHDN
FB
VC
V
IN
SW
1
2
3
4
9
GND
8
7
6
5
SYNC
SS
RT
SHDN
MS8E PACKAGE
8-LEAD PLASTIC MSOP
θ
JA
= 35°C/W TO 40°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
DD PACKAGE
8-LEAD (3mm 3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT3580EDD#PBF
LT3580IDD#PBF
LT3580EMS8E#PBF
LT3580IMS8E#PBF
LT3580HMS8E#PBF
LT3580MPMS8E#PBF
TAPE AND REEL
LT3580EDD#TRPBF
LT3580IDD#TRPBF
LT3580EMS8E#TRPBF
LT3580IMS8E#TRPBF
LT3580HMS8E#TRPBF
LT3580MPMS8E#TRPBF
PART MARKING*
LCXY
LCXY
LTDCJ
LTDCJ
LTDCJ
LTDCJ
PACKAGE DESCRIPTION
8-Lead (3mm
×
3mm) Plastic DFN
8-Lead (3mm
×
3mm) Plastic DFN
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-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 150°C
– 55°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/
3580fg
2
LT3580
ELECTRICAL CHARACTERISTICS
PARAMETER
Operating Voltage Range
Positive Feedback Voltage
Negative Feedback Voltage
Positive FB Pin Bias Current
Negative FB Pin Bias Current
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
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