Features and Benefits
- Wide Input Range: 3.5V to 25V
- Three Switching Regulators with Internal Power Switches: 3A Step-Down, 2A Step-Down, 1.5A Inverting/Boost
- Antiphase Switching Reduces Ripple
- Independent Shutdown/Soft-Start Pins
- Independent Power Good Indicators Ease Supply Sequencing
- Input Voltage Power Good Indicators Monitor Input Supply
- Uses Small Inductors and Ceramic Capacitors
- Constant 1.1MHz Switching Frequency
- Thermally Enhanced 28-Lead TSSOP Package
The LT1941 is a triple current mode DC/DC converter with internal power switches. Two of the regulators are step-down converters with 3A and 2A power switches. The third regulator can be configured as a boost, inverter or SEPIC converter and has a 1.5A power switch. All three converters are synchronized to a 1.1MHz oscillator. The two step-down converters run with opposite phase, reducing input ripple current. The output voltages are set with external resistor dividers and each regulator has independent shutdown and soft-start circuits. Each regulator generates a power good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs.
The high switching frequency offers several advantages by permitting the use of small inductors and ceramic capacitors, leading to a very small triple output solution. The constant switching frequency, combined with low impedance ceramic capacitors, result in low, predictable output ripple. With its wide input voltage range of 3.5V to 25V, the LT1941 regulates a broad array of power sources from 4-cell batteries and 5V logic rails to unregulated wall transformers, lead acid batteries and distributed-power supplies.
- Cable Modems
- DSL Modems
- Distributed Power Regulation
- Wall Transformer Regulation
- Disk Drives
- 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)
Demonstration circuit 621 is a 1.25MHz triple DC/DC switching converter using the LT1941. The LT1941 has two step-down converters and a third boost/inverting converter that can also be configured as a SEPIC or Cuk (inverting). The LT1941 has a wide 3.5V to 25V input voltage range; the demo board limits this range from 4.7V to 14V and is configured to provide 1.8V @ 2.4A, 3.3V @ 1.4A and –12V @ up to 550mA (depending on VIN).
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:
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Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.