Datasheet LT3507A (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Triple Monolithic Step-Down Regulator with LDO |
| Pages / Page | 30 / 1 — Features. Description. Wide Input Range: 4V to 36V. One 2.7A and Two 1.8A … |
| File Format / Size | PDF / 398 Kb |
| Document Language | English |
Features. Description. Wide Input Range: 4V to 36V. One 2.7A and Two 1.8A Output Switching
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LT3507A Triple Monolithic Step-Down Regulator with LDO
Features Description
n
Wide Input Range: 4V to 36V
The LT®3507A is a triple, current mode, DC/DC converter n
One 2.7A and Two 1.8A Output Switching
with internal power switches and a low dropout regulator.
Regulators with Internal Power Switches
The switching converters are step-down converters capable n
Low Dropout Linear Regulator with External
of generating one 2.7A output and two 1.8A outputs. All
Transistor
three converters are synchronized to a single oscillator. n
Antiphase Switching Reduces Ripple
The 2.7A output runs with opposite phase to the other two n Independent Run, Tracking/Soft-Start, and Power converters, reducing input ripple current. Each regulator Good Indicators Ease Supply Sequencing has independent shutdown and soft-start circuits, and n Uses Small Inductors and Ceramic Capacitors generates a power good signal when its output is in regu- n Adjustable, 250kHz to 2.5MHz Switching Frequency, lation, easing power supply sequencing and interfacing Synchronizable Over the Full Range with microcontrollers and DSPs. n User Programmable Overvoltage and Undervoltage The switching frequency is set with a single resistor yielding Lockouts a range of 250kHz to 2.5MHz. The high switching frequency n Thermally Enhanced, 38-Lead TSSOP and allows the use of small inductors and capacitors resulting 5mm × 7mm QFN Packages in a very small triple output supply. The constant switching
applications
frequency, combined with low impedance ceramic capaci- tors, results in low, predictable output ripple. Frequency n Automotive foldback and thermal shutdown provide protection against n Industrial Supplies fault conditions. The LT3507A provides higher output cur- n Distributed Power Regulation rent than available with the LT3507. n DSP Power L, LT, LTC, LTM, Burst Mode, 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 22µF VIN1 VIN2 VIN3 BOOST1 BOOST2
Start-Up Waveforms—Coincident Tracking
V 4.7µH 0.22µF OUT1 1.8V SW1 2.7A 0.22µF 18.7k 10µH VOUT2 100µF FB1 SW2 3.3V VOUT3 1.5A 680pF 33µF 15k 25.5k VC1 LT3507A 34.8k V 1V/DIV OUT2 VOUT2 FB2 VOUT4 BOOST3 V 15µH 0.22µF OUT3 VOUT1 5V 680pF 11k SW3 1.8A 25.5k VC2 53.6k 22µF FB3 BIAS 10.2k 680pF 25.5k 1ms/DIV 3507 TA01b VC3 DRIVE 24.3k VOUT4 FB4 2.5V RT/SYNC 0.3A 107k GND 11.5k 2.2µF fSW = 450kHz 3507A TA01a 3507afa For more information www.linear.com/LT3507A 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Package Description Typical Applications Related Parts
Features Description
n
Wide Input Range: 4V to 36V
The LT®3507A is a triple, current mode, DC/DC converter n
One 2.7A and Two 1.8A Output Switching
with internal power switches and a low dropout regulator.
Regulators with Internal Power Switches
The switching converters are step-down converters capable n
Low Dropout Linear Regulator with External
of generating one 2.7A output and two 1.8A outputs. All
Transistor
three converters are synchronized to a single oscillator. n
Antiphase Switching Reduces Ripple
The 2.7A output runs with opposite phase to the other two n Independent Run, Tracking/Soft-Start, and Power converters, reducing input ripple current. Each regulator Good Indicators Ease Supply Sequencing has independent shutdown and soft-start circuits, and n Uses Small Inductors and Ceramic Capacitors generates a power good signal when its output is in regu- n Adjustable, 250kHz to 2.5MHz Switching Frequency, lation, easing power supply sequencing and interfacing Synchronizable Over the Full Range with microcontrollers and DSPs. n User Programmable Overvoltage and Undervoltage The switching frequency is set with a single resistor yielding Lockouts a range of 250kHz to 2.5MHz. The high switching frequency n Thermally Enhanced, 38-Lead TSSOP and allows the use of small inductors and capacitors resulting 5mm × 7mm QFN Packages in a very small triple output supply. The constant switching
applications
frequency, combined with low impedance ceramic capaci- tors, results in low, predictable output ripple. Frequency n Automotive foldback and thermal shutdown provide protection against n Industrial Supplies fault conditions. The LT3507A provides higher output cur- n Distributed Power Regulation rent than available with the LT3507. n DSP Power L, LT, LTC, LTM, Burst Mode, 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 22µF VIN1 VIN2 VIN3 BOOST1 BOOST2
Start-Up Waveforms—Coincident Tracking
V 4.7µH 0.22µF OUT1 1.8V SW1 2.7A 0.22µF 18.7k 10µH VOUT2 100µF FB1 SW2 3.3V VOUT3 1.5A 680pF 33µF 15k 25.5k VC1 LT3507A 34.8k V 1V/DIV OUT2 VOUT2 FB2 VOUT4 BOOST3 V 15µH 0.22µF OUT3 VOUT1 5V 680pF 11k SW3 1.8A 25.5k VC2 53.6k 22µF FB3 BIAS 10.2k 680pF 25.5k 1ms/DIV 3507 TA01b VC3 DRIVE 24.3k VOUT4 FB4 2.5V RT/SYNC 0.3A 107k GND 11.5k 2.2µF fSW = 450kHz 3507A TA01a 3507afa For more information www.linear.com/LT3507A 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Package Description Typical Applications Related Parts
