Features and Benefits
- Wide Input Range: 3V to 36V Operating, 40V Maximum
- Short-Circuit Protected Over Full Input Range
- 2A Output Current Capability
- Adjustable/Synchronizable Fixed Frequency Operation from 250kHz to 2.2MHz
- Soft-Start/Tracking Capability
- Output Adjustable Down to 0.8V
- Adjustable Linear Regulator/Driver with 13mA Output Capability
- Power Good Comparator with Complimentary Outputs
- Low Shutdown Current: 12μA
- Thermally Enhanced 3mm × 3mm DFN or 16-Pin MSOP Package
The LT3500 is a current mode PWM step-down DC/DC converter with an internal 2.3A switch. The wide input range of 3V to 40V makes the LT3500 suitable for regulating power from a wide variety of sources, including automotive batteries, 24V industrial supplies and unregulated wall adapters.
Resistor-programmable 250kHz to 2.2MHz frequency range and synchronization capability enable optimization between efficiency and external component size. Cycle-by-cycle current limit, frequency foldback and thermal shutdown provide protection against a shorted output. The soft-start feature controls the ramp rate of the output voltage, eliminating input current surge during start-up, and also provides output tracking.
The LT3500 contains an internal NPN transistor with feedback control which can be configured as a linear regulator or as a linear regulator controller.
The LT3500’s low current shutdown mode (<12μA) enables easy power management in battery-powered systems.
- Automotive Battery Regulation
- Industrial Control
- Wall Transformer Regulation
- Distributed Power Regulation
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 1069A is a monolithic step-down switching regulator with LDO featuring LT3500. The demo circuit is designed for 5.0V and 3.3V outputs from a 6V to 36V input. The LDO output is configured as a post-regulator of the switching regulator output. The total current capability is up to 2A. The switching regulator can be synchronized to an external clock input or be resistor-programmed to a 250kHz to 2.2MHz internal oscillator. Programmable frequency allows for optimization between efficiency and external component size.
Cycle-by-cycle current limit, frequency foldback and thermal shutdown provide protections against a shorted output. The soft-start feature controls the ramp rate of the output voltage, eliminates input current surge during startup, and also provides output tracking.
Documentation & Resources
R530 Reliability Data3/26/2018
DC1069A - Demo Manual9/24/2009
36Vin Multichannel Bucks8/18/2016
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
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Models for the following parts are available in LTspice:
LT3500 Companion Parts
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.