Step-Down Regulator. LT3507A Datasheet

LT3507A Regulator. Datasheet pdf. Equivalent

Part LT3507A
Description Triple Monolithic Step-Down Regulator
Feature FEATURES n Wide Input Range: 4V to 36V n One 2.7A and Two 1.8A Output Switching Regulators with In.
Manufacture Linear
Datasheet
Download LT3507A Datasheet



LT3507A
FEATURES
n Wide Input Range: 4V to 36V
n One 2.7A and Two 1.8A Output Switching
Regulators with Internal Power Switches
n Low Dropout Linear Regulator with External
Transistor
n Antiphase Switching Reduces Ripple
n Independent Run, Tracking/Soft-Start, and Power
Good Indicators Ease Supply Sequencing
n Uses Small Inductors and Ceramic Capacitors
n Adjustable, 250kHz to 2.5MHz Switching Frequency,
Synchronizable Over the Full Range
n User Programmable Overvoltage and Undervoltage
Lockouts
n Thermally Enhanced, 38-Lead TSSOP and
5mm × 7mm QFN Packages
APPLICATIONS
n Automotive
n Industrial Supplies
n Distributed Power Regulation
n DSP Power
LT3507A
Triple Monolithic Step-Down
Regulator with LDO
DESCRIPTION
The LT®3507A is a triple, current mode, DC/DC converter
with internal power switches and a low dropout regulator.
The switching converters are step-down converters capable
of generating one 2.7A output and two 1.8A outputs. All
three converters are synchronized to a single oscillator.
The 2.7A output runs with opposite phase to the other two
converters, reducing input ripple current. Each regulator
has independent shutdown and soft-start circuits, and
generates a power good signal when its output is in regu-
lation, easing power supply sequencing and interfacing
with microcontrollers and DSPs.
The switching frequency is set with a single resistor yielding
a range of 250kHz to 2.5MHz. The high switching frequency
allows the use of small inductors and capacitors resulting
in a very small triple output supply. The constant switching
frequency, combined with low impedance ceramic capaci-
tors, results in low, predictable output ripple. Frequency
foldback and thermal shutdown provide protection against
fault conditions. The LT3507A provides higher output cur-
rent than available with the LT3507.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
5V, 3.3V, 2.5V and 1.8V Step-Down Regulator
VIN
6V TO 36V
VOUT1
1.8V
2.7A
VOUT3
5V
1.8A
22µF
4.7µH
VIN1 VIN2 VIN3
BOOST1
BOOST2
0.22µF
SW1
18.7k
100µF
15k
25.5k
VOUT2
15µH
680pF
FB1
VC1
LT3507A
0.22µF BOOST3
SW3
53.6k
22µF
10.2k
25.5k 680pF
FB3
VC3
SW2
FB2
VC2
BIAS
DRIVE
RT/SYNC
107k GND
FB4
0.22µF
10µH
34.8k
680pF 25.5k 11k
24.3k
11.5k
VOUT2
3.3V
33µF 1.5A
2.2µF
VOUT4
2.5V
0.3A
fSW = 450kHz
3507A TA01a
Start-Up Waveforms—Coincident Tracking
1V/DIV
VOUT3
VOUT2
VOUT4
VOUT1
1ms/DIV
3507 TA01b
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LT3507A
LT3507A
ABSOLUTE MAXIMUM RATINGS (Note 1)
VIN Pins....................................................... –0.3V to 36V
BOOST Pins...............................................................55V
BOOST Above SW......................................................25V
PGOOD Pins...............................................................36V
BIAS Pin.....................................................................16V
TRK/SS, VC, FB, RT/SYNC Pins....................................6V
RUN, OVLO, UVLO Pins............................................ VIN1
DRIVE Pin....................................................................5V
Operating Junction Temperature Range (Notes 2, 5)
LT3507AE, LT3507AI.......................... –40°C to 125°C
LT3507AH........................................... –40°C to 150°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
TSSOP Only....................................................... 300°C
PIN CONFIGURATION
TOP VIEW
BOOST1 1
VIN1
VIN1
VINSW
OVLO
2
3
4
5
UVLO 6
VC1 7
TRK/SS1 8
FB1 9
PGOOD1 10
PGOOD2 11
PGOOD3 12
38 37 36 35 34 33 32
39
GND
13 14 15 16 17 18 19
31 VIN2
30 VIN2
29 SW2
28 SW2
27 BOOST2
26 TRK/SS4
25 FB4
24 DRIVE
23 VC2
22 FB2
21 TRK/SS2
20 FB3
UHF PACKAGE
38-LEAD (5mm × 7mm) PLASTIC QFN
θJA = 34°C/W
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
VIN3 1
SW1 2
SW1 3
BOOST1 4
VIN1
VIN1
VINSW
OVLO
5
6
7
8
UVLO 9
VC1 10
TRK/SS1 11
FB1 12
PGOOD1 13
PGOOD2 14
PGOOD3 15
RT/SYNC 16
RUN1 17
RUN2 18
RUN3 19
TOP VIEW
39
GND
38 SW3
37 BOOST3
36 VIN2
35 VIN2
34 NC
33 SW2
32 BOOST2
31 TRK/SS4
30 FB4
29 DRIVE
28 VC2
27 NC
26 FB2
25 TRK/SS2
24 FB3
23 VC3
22 TRK/SS3
21 BIAS
20 GND
FE PACKAGE
38-LEAD PLASTIC TSSOP
θJA = 24°C/W
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT3507AEUHF#PBF
LT3507AIUHF#PBF
LT3507AHUHF#PBF
LT3507AEFE#PBF
LT3507AEUHF#TRPBF
LT3507AIUHF#TRPBF
LT3507AHUHF#TRPBF
LT3507AEFE#TRPBF
3507A
3507A
3507A
LT3507AFE
38-Lead (5mm × 7mm) Plastic QFN
38-Lead (5mm × 7mm) Plastic QFN
38-Lead (5mm × 7mm) Plastic QFN
38-Lead Plastic TSSOP
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–40°C to 125°C
LT3507AIFE#PBF
LT3507AIFE#TRPBF
LT3507AFE
38-Lead Plastic TSSOP
–40°C to 125°C
LT3507AHFE#PBF
LT3507AHFE#TRPBF
LT3507AFE
38-Lead Plastic TSSOP
–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.
*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/
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3507af





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