Switching Regulator. LT3505 Datasheet

LT3505 Regulator. Datasheet pdf. Equivalent

Part LT3505
Description Step-Down Switching Regulator
Feature www.DataSheet4U.com LT3505 1.2A, Step-Down Switching Regulator in 3mm × 3mm DFN DESCRIPTION The LT®.
Manufacture Linear Technology
Total Page 24 Pages
Datasheet
Download LT3505 Datasheet



LT3505
www.DataSheet4U.com
LT3505
1.2A, Step-Down
Switching Regulator in
3mm × 3mm DFN
FEATURES
! Wide Input Range: 3.6V to 36V Operating,
40V Maximum
! Up to 1.2A Output Current
! Resistor-Programmable Fixed-Frequency Operation
from 200kHz to 3MHz
! Output Adjustable Down to 780mV
! Short-Circuit Robust
! Uses Tiny Capacitors and Inductors
! Soft-Start
! Low Shutdown Current: <2µA
! Low VCESAT Switch: 350mV at 1A
! Thermally Enhanced, Low Profile 3mm x 3mm
DFN-8 and MSOP-8 Packages
APPLICATIONS
! Automotive Battery Regulation
! Industrial Control Supplies
! Wall Transformer Regulation
! Distributed Supply Regulation
! Battery-Powered Equipment
DESCRIPTION
The LT®3505 is a current mode PWM step-down DC/DC
converter with an internal 1.4A power switch. The wide
operating input range of 3.6V to 36V (40V maximum)
makes the LT3505 ideal for regulating power from a wide
variety of sources, including unregulated wall transform-
ers, 24V industrial supplies and automotive batteries. The
oscillator can be programmed for high frequency operation
allowing the use of tiny, low cost external components or
it can be programmed for lower frequency operation to
maximize efficiency.
Cycle-by-cycle current limit provides protection against
shorted outputs and soft-start eliminates input current
surge during start-up. The low current (<2µA) shutdown
mode provides output disconnect, enabling easy power
management in battery-powered systems.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
750kHz, 3.3V Step-Down Converter
VIN
4.2V TO 36V
ON OFF
VIN BOOST
SHDN
LT3505
SW
FB
RT GND
VC
0.1µF 10µH
36.5k
11.3k
22pF
VOUT
3.3V
1.1A, VIN > 5V
1.2A, VIN > 8V
10µF
75.0k
1µF
69.8k
68pF
3505 TA01
Efficiency
90
85
80
75
70
65
60 VIN = 12V
55
VOUT = 3.3V
fSW = 750kHz
L = 10 H
50
0 0.2 0.4 0.6 0.8
LOAD CURRENT (A)
1.0
1.2
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LT3505
LT3505www.DataSheet4U.com
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Voltage (VIN)....................................................40V
BOOST Pin Voltage ..................................................50V
BOOST Pin Above SW Pin.........................................25V
SHDN Pin..................................................................40V
FB Pin .........................................................................6V
VC Pin .........................................................................3V
RT Pin .........................................................................3V
Operating Temperature Range (Note 2)
LT3505E .............................................. –40°C to 85°C
LT3505I ............................................. –40°C to 125°C
Maximum Junction Temperature .......................... 125°C
Storage Temperature Range................... –65°C to 150°C
PIN CONFIGURATION
TOP VIEW
BOOST 1
8 VC
SW 2 9 7 FB
VIN 3
6 RT
SHDN 4
5 GND
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 43°C/W, θJC = 5°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
TOP VIEW
BOOST 1
8 VC
SW 2
VIN 3
9
7 FB
6 RT
SHDN 4
5 GND
MS8E PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 125°C, θJA = 40°C/W, θJC = 5°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
LT3505EDD#PBF
LT3505EDD#TRPBF
LCHB
8-Lead (3mm x 3mm) Plastic DFN
LT3505IDD#PBF
LT3505IDD#TRPBF
LCHC
8-Lead (3mm x 3mm) Plastic DFN
LT3505EMS8E#PBF
LT3505EMS8E#TRPBF LTCNX
8-Lead Plastic MSOP
LT3505IMS8E#PBF
LT3505IMS8E#TRPBF LTCNY
8-Lead Plastic MSOP
LEAD BASED FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
LT3505EDD
LT3505EDD#TR
LCHB
8-Lead (3mm x 3mm) Plastic DFN
LT3505IDD
LT3505IDD#TR
LCHC
8-Lead (3mm x 3mm) Plastic DFN
LT3505EMS8E
LT3505EMS8E#TR
LTCNX
8-Lead Plastic MSOP
LT3505IMS8E
LT3505IMS8E#TR
LTCNY
8-Lead Plastic MSOP
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
–40°C to 125°C
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
–40°C to 125°C
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