Step-Down Regulator. LT3509 Datasheet

LT3509 Regulator. Datasheet pdf. Equivalent

Part LT3509
Description 700mA Step-Down Regulator
Feature www.DataSheet4U.com LT3509 Dual 36V, 700mA Step-Down Regulator DESCRIPTION The LT®3509 is a dual, c.
Manufacture Linear Technology
Total Page 24 Pages
Datasheet
Download LT3509 Datasheet



LT3509
www.DataSheet4U.com
LT3509
Dual 36V, 700mA
Step-Down Regulator
FEATURES
n Two 700mA Switching Regulators with Internal
Power Switches
n Wide 3.6V to 36V Operating Range
n Over-Voltage Lockout Protects Circuit Through 60V
Supply Transients
n Short Circuit Robust
n Low Dropout Voltage 95% Maximum Duty Cycle
n Adjustable 300kHz to 2.2MHz Switching Frequency
Synchronizable Over the Full Range
n Uses Small Inductors and Ceramic Capacitors
n Integrated Boost Diodes
n Internal Compensation
n Thermally Enhanced 14 Lead (4 mm × 3 mm)
DFN and 16 Lead MSOP Packages
APPLICATIONS
n Automotive Electronics
n Industrial Controls
n Wall Transformer Regulation
n Networking Devices
n CPU, DSP, or FPGA Power
DESCRIPTION
The LT®3509 is a dual, current mode, step-down switching
regulator, with internal power switches each capable of
providing 700mA output current. This regulator provides a
compact and robust solution for multi-rail systems in harsh
environments. It incorporates several protection features
including overvoltage lockout and cycle by cycle current
limit. Thermal shutdown provides additional protection.
The loop compensation components and the boost diodes
are integrated on-chip. Switching frequency is set by a
single external resistor. External synchronization is also
possible. The high maximum switching frequency allows
the use of small inductors and ceramic capacitors for low
ripple. Constant frequency operation above the AM band
avoids interference with radio reception, making the LT3509
well suited for automotive applications. Each regulator
has an independent shutdown and soft-start control pin.
When both converters are powered down, the common
circuitry enters a low current shutdown state.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
6.5V TO 36V
(Transient
to 60V)
3.3V
700mA
10μF
3.3V and 5V Dual Output Step-Down Converter
2.2μF
6.8μH
0.1μF
31.6k
MBRM140
10.2k
1nF
VIN
BOOST1
BD
BOOST2
SW1 SW2
LT3509
DA1 DA2
FB1 FB2
RUN/SS1 RUN/SS2
SYNC
GND
RT
0.1μF 10μH
MBRM140
53.6k
60.4k
1nF
10.2k
5V
700mA
22μF
fSW = 700kHz
3509 TA01a
Efficiency
90
85 VOUT = 5V
80
VOUT = 3.3V
75
70
65
60
55 VIN = 12V
fSW = –700kHz
50
0.0 0.1 0.2 0.3 0.4 0.5
LOAD CURRENT (A)
0.6 0.7
3509 TA01b
3509f
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LT3509
LT3509www.DataSheet4U.com
ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN Pin (Note 2) ........................................................60V
BD Pin.......................................................................20V
BOOST Pins ..............................................................60V
BOOST Pins above SW .............................................30V
RUN/SS, FB, RT, SYNC pins ........................................6V
Operating Junction Temperature Range (Notes 3, 5)
LT3509E............................................. –40°C to 125°C
LT3509I.............................................. –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec.)
MSE16 Package................................................ 300°C
PIN CONFIGURATION
TOP VIEW
DA1 1
14 FB1
BOOST1 2
13 RUN/SS1
SW1 3
12 BD
VIN 4 15 11 SYNC
SW2 5
10 RT
BOOST2 6
9 RUN/SS2
DA2 7
8 FB2
DE14 PACKAGE
14-LEAD (4mm s 3mm) PLASTIC DFN
θJA = 43°C/W, θJC = 4.3°C/W
EXPOSED PAD (PIN 15) IS GND, MUST BE SOLDERED TO PCB
DA1 1
BOOST1 2
SW1 3
VIN 4
VIN 5
SW2 6
BOOST2 7
DA2 8
TOP VIEW
17
16 FB1
15 RUN/SS1
14 AGND
13 BD
12 SYNC
11 RT
10 RUN/SS2
9 FB2
MSE PACKAGE
16-LEAD PLASTIC MSOP
θJA = 43°C/W, θJC = 4.3°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING* PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT3509EDE#PBF
LT3509EDE#TRPBF
3509
14-Lead (4mm × 3mm) Plastic DFN
–40°C to 125°C
LT3509IDE#PBF
LT3509IDE#TRPBF
3509
14-Lead (4mm × 3mm) Plastic DFN
–40°C to 125°C
LT3509EMSE#PBF
LT3509EMSE#TRPBF
3509
16-Lead Plastic MSOP with Exposed Pad –40°C to 125°C
LT3509IMSE#PBF
LT3509IMSE#TRPBF
3509
16-Lead Plastic MSOP with Exposed Pad –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/
3509f
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