LT3507A: Triple Monolithic Step-Down Regulator with LDO Data Sheet1/11/2016388K
Features and Benefits
- Wide Input Range: 4V to 36V
- One 2.7A and Two 1.8A Output Switching Regulators with Internal Power Switches
- Low Dropout Linear Regulator with External Transistor
- Antiphase Switching Reduces Ripple
- Independent Run, Tracking/Soft-Start, and Power Good Indicators Ease Supply Sequencing
- Uses Small Inductors and Ceramic Capacitors
- Adjustable, 250kHz to 2.5MHz Switching Frequency, Synchronizable Over the Full Range
- User Programmable Overvoltage and Undervoltage Lockouts
- Thermally Enhanced, 38-Lead TSSOP and 5mm × 7mm QFN Packages
The LT3507A 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 regulation, 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 capacitors, results in low, predictable output ripple. Frequency foldback and thermal shutdown provide protection against fault conditions. The LT3507A provides higher output current than available with the LT3507.
|LT3507||2.5A, 1.5A, 1.5A||5x7 QFN-38|
|LT3507A||2.7A, 1.8A, 1.8A||5x7 QFN-38, TSSOP-38E|
- Industrial Supplies
- Distributed Power Regulation
- DSP Power
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demo circuit 1781A is a Triple Monolithic Step-Down Regulator with LDO featuring the LT3507A. The demo circuit is designed for 1.8V, 3.3V, 5.0V and 2.5V outputs from a 7V to 36V input. The current capability of each channel is 2.7A, 1.5A, 1.8A and 0.3A respectively. Independent input voltage, feedback, soft-start and power good pins for each channel simplify complex power supply tracking/sequencing requirements.
All three converters are either synchronized to a common external clock input or single-resistor programmable from 250kHz to 2.5MHz using internal oscillator. At all frequencies, a 180° phase shift between VOUT1 and the other two outputs is maintained, reducing input voltage ripple and component size. Programmable frequency allows for optimization between efficiency and external component size.
Documentation & Resources
R530 Reliability Data3/26/201820 K
DC1781A - Demo Manual9/26/2011378K
36Vin Multichannel Bucks8/18/2016222K
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